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micro-controller using CAN bus data for ancillary control


2X044

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1 hour ago, Puffwagon said:

In the case of a complete loss of oil pressure you want an immediate engine shutdown and also a failure to restart. Immediate shutdown is the only suitable way of dealing with a complete oil pressure loss. In the case of oil pressure going low ie 10 psi, a complete throttle shut with the inability to reopen the throttle until the ignition is cycled is suitable.

For fuel related things, the only thing we are concerned about is the engine leaning out. A complete loss of fuel pressure solves itself, the engine shuts down, however should be addressed. A partial loss of fuel pressure is where things get dangerous and a suitable fail-safe for this is to close the throttle. An issue I see here is losing the FPR reference line and still having 60psi of fuel pressure, when you should have 100psi. When you return to cruising, the fuel pressure will fall below 60psi with the vacuum, so using a fuel pressure number as a dumb/ on off fail-safe wont work. While we may be able to integrate a wideband signal to activate the fail-safe at a set voltage, we still see the same issue where we can't just pick a number, due to the wideband number being suitable at decel but not at WOT. At a minimum we need a map reference as well as a wideband reference to control the fail-safe, preferably with a TPS reference to cover rapid throttle closing after a run where the fuel might cut but still have a high map value. While the fail-safe may mimic the action of lifting the throttle after a run, it is preferable to not have the vehicle enter a failure mode unnecessarily.

Preaching to the choir here but these things need to happen instantly. A flashing warning for those that are a bit slow on shutting the ignition off is something to add but not strictly necessary.

Anyhow there's a few cents :)

If we can get the PCM to respond quickly enough, it would be reasonably straight forward to compare the fuel pressure to the boost pressure (available on CAN) and create a simple calculation to determine if the fuel pressure is low.

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18 minutes ago, 2X044 said:

This is the approach that I tested, unfortuneately the logged temperature took 5+ seconds to reach its new level, so even with an instantaneous change in resistance, it doesn't look like we will have a timely response. Kirby was going to check if there is a way to hasten the system. I will check if the PCM responds rapidly even if the log shows it changes slow, but I don't like my chances.

I found that the PCM ignores a resistance that is too low (~below 100 Ohms), it also seems to ignore very high resistance. Everything in between seems to be accepted, when translated to the calculated "coolant temp" that value tops out at 122 deg C regardless of how high the CHT goes.

Short answer:

CHT is filtered by auF11645 Time constant for filtered CHT. which is set to 1.2 seconds by default. Change this to make it move instantly.

Datalog MID33881 for CHT Fault - This will be set if the AD count exceeds auF10305 (1018) or goes below auF11617 (10)

 

Long Answer:

Next the following may assist you. This is the CHT transfer function for A/D counts per degree. There are two transfer functions auF1361 and auF2557

it uses the "dual resistor" model when the inferred temp is above auF12365 Use dual resistor system above this temperature. which is set to 80°C by default.

image.png.ab08b02a35e81fb7f814c0cdfb6f324e.pngimage.png.5bf4f1f17faa99612d646a5de41ac181.png

 

Modify the following scalars to adjust how the over temperature modes function. They don't have proper descriptions yet but I have named them in this post to assist.

There are 3 over temp levels.

Level 1 P1285 is set and the overtemp lamp will come on.

Level 2 P1299 is set and torque reduction will occur by shutting down the number of cylinders set in auF10294

Level 3 Number of cylinders specified in auF1613 will be turned off

I believe Level 2/3 are set up to shut down all cylinders by default, however you can set it up to be staged. Eg run on 3 cylinders, then full engine shutdown.

 

auF1544 CHT Level 1 temperature setpoint (indicator lamp turns on)  126 °C

auF10952 CHT Level 1 P1285 Temperature Hysteresis (falling edge, eg must be lower than auF1544 ) = 110 °C

auF2280 CHT Level 2 Temperature setpoint = 126°C

auF1870 CHT Level 3 Temperature setpoint (cylinder shutdown) = 204°C

auF11550 Level1 P1285 Temperature Setpoint

 

The count setpoints are I think are in multiples of how often the code is called. So this may vary on BA vs BF etc. The max number is 250. It might be milliseconds.

auF11550 Level 1 P1285 Count Setpoint

auF12210 Level2 P1299 Count Setpoint

auF12214 Level 3 CHT Critical Level Count Setpoint

image.png.0eb517ff41278f911f341857bee6592e.png

 

Datalog MID06769 for Level 1 current count

Datalog MID06770 for Level 2 current count

Datalog MID06771 for Level 3 current count

Datalog MID33881 for CHT Fault - This will be set if the AD count exceeds auF10305 (1018) or goes below auF11617 (10)

 

When testing make sure the engine has been running for this long otherwise fail safe cooling is not enabled

auF12786 Time allowed in run mode before entry into fail safe cooling is permitted. = 10 seconds

 

You can manually force fail safe cooling by setting auF1549 = 1. This is if you want to see what actually happens in fail safe cooling mode.

 

auF11665 Time since power up to keep fail safe cooling  light on for bulb test. 

This is how long fail safe cooling must be active before the coolant lamp is turned on.

 

auF12949 Frequency of the engine coolant light flashing on/off. = 1 second

This is the interval at which the engine coolant light will flash

 

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Hi Everyone,

It's come to our attention that @2X044 was having some issues progressing and accessing these parameters because they were not available outside of the Workshop Edition.

The staff here at PCMTec HQ is impressed with the progress so far and to keep this project moving and assist in bringing this idea and product to market we have upgraded @2X044's PCMTec account to One Car Workshop. We are happy to support the work they are doing and the possibility of bringing something really useful to the community.
 
Keep up the good work!
 

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A huge thanks to the PCMtec team.

In response to their generosity, I have committed to commercialising this product, or if I can't, then I will release everything I've done under an open source license so that others can freely use my work.

Thanks again!

Feeling motivated!

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On 11/16/2022 at 12:39 PM, Roland@pcmtec said:

Short answer:

CHT is filtered by auF11645 Time constant for filtered CHT. which is set to 1.2 seconds by default. Change this to make it move instantly.

Datalog MID33881 for CHT Fault - This will be set if the AD count exceeds auF10305 (1018) or goes below auF11617 (10)

 

Long Answer:

Next the following may assist you. This is the CHT transfer function for A/D counts per degree. There are two transfer functions auF1361 and auF2557

it uses the "dual resistor" model when the inferred temp is above auF12365 Use dual resistor system above this temperature. which is set to 80°C by default.

image.png.ab08b02a35e81fb7f814c0cdfb6f324e.pngimage.png.5bf4f1f17faa99612d646a5de41ac181.png

 

Modify the following scalars to adjust how the over temperature modes function. They don't have proper descriptions yet but I have named them in this post to assist.

There are 3 over temp levels.

Level 1 P1285 is set and the overtemp lamp will come on.

Level 2 P1299 is set and torque reduction will occur by shutting down the number of cylinders set in auF10294

Level 3 Number of cylinders specified in auF1613 will be turned off

I believe Level 2/3 are set up to shut down all cylinders by default, however you can set it up to be staged. Eg run on 3 cylinders, then full engine shutdown.

 

auF1544 CHT Level 1 temperature setpoint (indicator lamp turns on)  126 °C

auF10952 CHT Level 1 P1285 Temperature Hysteresis (falling edge, eg must be lower than auF1544 ) = 110 °C

auF2280 CHT Level 2 Temperature setpoint = 126°C

auF1870 CHT Level 3 Temperature setpoint (cylinder shutdown) = 204°C

auF11550 Level1 P1285 Temperature Setpoint

 

The count setpoints are I think are in multiples of how often the code is called. So this may vary on BA vs BF etc. The max number is 250. It might be milliseconds.

auF11550 Level 1 P1285 Count Setpoint

auF12210 Level2 P1299 Count Setpoint

auF12214 Level 3 CHT Critical Level Count Setpoint

image.png.0eb517ff41278f911f341857bee6592e.png

 

Datalog MID06769 for Level 1 current count

Datalog MID06770 for Level 2 current count

Datalog MID06771 for Level 3 current count

Datalog MID33881 for CHT Fault - This will be set if the AD count exceeds auF10305 (1018) or goes below auF11617 (10)

 

When testing make sure the engine has been running for this long otherwise fail safe cooling is not enabled

auF12786 Time allowed in run mode before entry into fail safe cooling is permitted. = 10 seconds

 

You can manually force fail safe cooling by setting auF1549 = 1. This is if you want to see what actually happens in fail safe cooling mode.

 

auF11665 Time since power up to keep fail safe cooling  light on for bulb test. 

This is how long fail safe cooling must be active before the coolant lamp is turned on.

 

auF12949 Frequency of the engine coolant light flashing on/off. = 1 second

This is the interval at which the engine coolant light will flash

 

Thanks Roland,

I can see a few options to make the response quicker.

1 - Reduce the time constant.

2 - Reduce the level 3 setpoint (150 deg C instead of 200).

3 - Increase the temperature corresponding with low A/D counts.

The change-over between the single and dual resistor ranges also appears to add a delay. It may be that the system can only work quickly when the CHT is in the higher range. The cold start rev-limiter crew might not be protected.

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Hey just a thought, instead of having the pcm do all of the work, what if we used the ancillary box to trigger a relay that would turn the ignition off? This would work for a zero oil pressure situation.

Sending an overboost signal to the pcm triggers an injector cut, that would be suitable for low oil pressure.

I've dealt with a territory that had a throttle closing issue and it turned out to be some pins not connecting in the main harness. Due to the way the throttle body is managed, you could either send a failed throttle body signal to the pcm for a lean out or as per the first paragraph, use the ancillary box to trigger a relay that disconnects the throttle body, hence closing it.

Anyhow there's something, maybe you've already thought about all of it, maybe not 🙃

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Like all things there is lots of ways to skin a cat, the best thing about the CHT method (which we discussed in the office) - was that you can stage it, and by default the first stage adds a bunch of fuel - adding cooling and reducing your power. 

In the event of a entire LoS of oil pressure or fuel pressure a straight engine kill might be useful, but it might also be incredibly dangerous depending on what speed/gear/corner you are turning.

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You have to turn the engine off with complete oil pressure loss. I recent had an oil pump body shatter and the engine kept running at wot, over 600awkw at that particular time, until it seized a cam in the head, snapped the timing chain, bent all the valves and damaged the cam and cam journals. A very expensive exercise lol. A complete engine shutdown would have at least prevented the head and valve damage.

With low fuel pressure you don't need an engine shutdown.

Lots of people run more than one fuel pump. Losing a pump will create the low fuel pressure scenario that puts an engine in danger and the best way to save the engine is to close the throttle.

While there may be more than one way to achieve those ends, there are definite things that need to happen to prevent engine damage.

If the CHT fmem can take care of everything that's great, at any rate I was just adding ideas to the pile 😃

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More testing done. Changing the CHT time constant works really well as per graphs below which compare a 0.1s time constant to the original 1.2s time constant. Takes a 12th of the time to change as expected.

image.thumb.png.1bcb2d86a1c14f851ee2e750ba464475.png

With the 0.1s TC and starting at a CHT of 90 deg C and a step change to 220 deg C, 150 deg C is reached in 0.1s and 200 deg C is reached in 0.2s.

After logging the A/D counts I changed the appropriate values to push up the temp even higher. When I changed the upper end of the dual resistor curve to 700 deg F I just got a CHT fault. More investigation needed, I noticed there was a CHT "calibrated range" which may be in play.

 

Another issue was experienced too. I did a "running test" and found that even with a CHT of 220 deg C, the engine didn't stall every time. image.thumb.png.d79cc74e39506729d6ecd54122752e62.png

The PCM is configured to shut down 12 cylinders when critical temp (204.4) is reached. I might try playing with this number to see if 12 means something else like 1 cylinder every 12... My car shakes about a bit while doing this though so don't want to spend too long testing this bit.

image.thumb.png.e20c9555c4c2730e6d691e904832064f.png

I was also a little concerned that the gauge in the dash might get damaged from trying to move so quickly, but it just meanders up there.

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very intrigued by this, i really dont know what is going on with 90% of it. but would this be a viable option for the NA+T guys?
as that seems to be a growing community.  being able to use computer  with an add on like this for boost control, would be great. 

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12 hours ago, dat111 said:

very intrigued by this, i really dont know what is going on with 90% of it. but would this be a viable option for the NA+T guys?
as that seems to be a growing community.  being able to use computer  with an add on like this for boost control, would be great. 

Hi @dat111, there are two goals of the system that I am working on, the first is a boost control system that mimics the factory PCM turbo strategy. This is quite simple from an electronics side but quite tricky (for me anyway) for the software side. The second function is a protection system for the engine to protect from low oil and fuel pressure. This is quite simple software wise but a little tricker electronics wise.

I've been spending my time recently working on the protection side of things as my test hack has a boost creep issue (stuck/sticky wastegate) that would prevent me from doing any testing on the boost control system. I don't want to pull it apart to fix as that would stop my testing on the protection system while it is apart.

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2 hours ago, Puffwagon said:

How's it going @2X044?

Slowly,it was my birthday on Monday and I went away for the weekend. I am planning on doing more testing tomorrow to try and work out why the engine isn't shutting down.

I need to get better with the PCMtec logger as I'm interested in working out how many cylinders are shutting down (injector pulsewidth per cylinder) and also what the idle air flow is doing. Once I can get it shutting down from idle, I will have the fun of trying to get it to work at higher loads/rpms.

I've found a few more parameters that I can play with, such as the maximum requestable torque under fail safe cooling conditions.

@Puffwagon in your experience and considering that the engine is going to keep turning even with all cylinders shut-down due to the clutch/converter still being driven by the back wheels, would cutting requestable torque to SFA be enough to get the driver to realise they need to put the car in neutral and kill ignition ASAP.

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1 hour ago, Puffwagon said:

I'll have to reply tomorrow, ran out of time today.

No worries. One thing to add to the thought process is, we can shutdown the engine before it hits 0 psi oil pressure, perhaps using both a threshold and a rate of change parameter, for example 25psi and dropping faster than 5 psi a second.

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Yes, if you can limit the engine's ability to rev up then that will give the user time to react.

There are 2 types of users to think about, the "I put petrol in and it goes vroom" type that can't catch a preventable failure and the others that are alert and aware enough to react to a torque reduction event. Hopefully we can accommodate both but we can only do what we can do.

Torque reduction for fuel safety would work as long as all the injectors were 100% switched off for long enough for the engine to drop boost pressure. You wouldn't want a partial cut as it'll still have 3 cylinders firing and they can still be damaged by running lean.

We have torque reduction during a gearshift in an auto car, mostly it's done by reducing ignition timing. Perhaps this can be used for something.

Rate of change for oil pressure below a certain threshold should work fine.

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2 hours ago, Puffwagon said:

Yes, if you can limit the engine's ability to rev up then that will give the user time to react.

There are 2 types of users to think about, the "I put petrol in and it goes vroom" type that can't catch a preventable failure and the others that are alert and aware enough to react to a torque reduction event. Hopefully we can accommodate both but we can only do what we can do.

Torque reduction for fuel safety would work as long as all the injectors were 100% switched off for long enough for the engine to drop boost pressure. You wouldn't want a partial cut as it'll still have 3 cylinders firing and they can still be damaged by running lean.

We have torque reduction during a gearshift in an auto car, mostly it's done by reducing ignition timing. Perhaps this can be used for something.

Rate of change for oil pressure below a certain threshold should work fine.

Thanks for the feedback. I'll give it more thought and see what can be done with the PCM.

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More testing done today and have the engine shutting down near enough immediately on sending a high temp signal. I've recorded some log files for anyone interested. First one is a slow sweep from 147 up to 220 degrees, this shows that the shutdown is happening in two steps, first a reduction in torque to 0.33 multiplier, then 10ish seconds later, a further reduction to zero.

24-11-2022 01-30-56 PM Log.teclog

By changing auF11960 to 1 second, this brings the shutdown on nearly immediately. image.thumb.png.2895f88c2fefe83ad8ef0d9b8c645c70.png

This log file shows the reduction in torque to zero occurring almost immediately.

24-11-2022 02-05-10 PM Logzerotqafter1s.teclog

Finally this log is a bunch of running tests, the first being to 220 deg C, the next ones to 195 deg C (below critical temp) and the final ones to 147 deg C. Need to do more tests between 126 and 137 deg C to see what happens between CHT overtemp start and CHT overtemp torque reduction.

24-11-2022 02-15-10 PM LogRunning147deg.teclog

A few things I noticed but could be looking in the wrong spot, I haven't seen any "enrichment" to the contrary the lambse goes to 1.05.

The torque reduction due to ECT (throttle) is active and drops from 255 to approx 5. Suggesting that the throttle is being used by the system not just fuel-cut.

The torque reduction due to injector cut is also active and drops to 0.333 before dropping to zero when above critical. When below critical it drops to 0.5 and never recovers or changes or seems to have any effect, I suspect this will go back to normal when the temperature drops below 136 deg C.

The torque source changes from "driver demand" to "target RPM" immediately on high temp but I can't seem to see what the "target RPM" is.

 

I've looked at a couple of aftermarket systems to see how they implement engine protection and one uses a significantly reduced rev limit with a fuel cut limiter. They claim this is safer than a complete shutdown due to allowing a car to be moved to a safe place (either on track or on the freeway). It seems like we could do something similar but I haven't yet found the parameters.

 

I've also ordered a 3 wire oil pressure sensor that can serve as the oil pressure input to the system though for testing I'm going to have to simulate the readings as I don't fancy running low on oil pressure intentionally. If someone has an ex-taxi that they don't mind destroying we can test it on that. The sensor is 0-150psi, has anyone ever used an oil pressure sensor to measure fuel pressure? I can't see why you can't unless they aren't E85 resistant.

 

Any ideas on parameters to achieve a rev limiter would be appreciated.

 

 

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2 hours ago, 2X044 said:

has anyone ever used an oil pressure sensor to measure fuel pressure?

Nope but I have one here and was waiting for a reason to try it out.

One thing I saw in the logs is that the oil temp is only around 20C. I'm not sure if it will change anything when this value is higher but it would be worth checking.

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16 hours ago, hjtrbo said:

@2X044 perhaps. I have 2 Honeywell MIP series selected for fuel pressure and oil pressure duty. Data sheet supports anything automotive and as such I am confident that this is a good purchase. Roughly $130AUD each Pressure Sensor 100PSI Honeywell (efihardware.com).

Thansk @hjtrbo, I hadn't found those sensors in my search. I like the idea of a Honeywell sensor over some no-name sensor. I see they make a 100 psi and a 150 psi sensor, most companies I've looked at tend to use the 150 psi but the unit you linked is 100 psi. The SAAS sensor that I ordered is also 150 psi. Can anyone see a need for a 150 over 100?

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A small update, I've just ordered the connectors to be able to interface with the engine oil temp sensor the same way that I am interfacing with the CHT sensor. Depending upon what we are trying to achieve with the engine, I've found some EOT parameters that may be more suited to our needs. Let's hope that I don't also need to interface with the Intake AIr Temp sensor too.

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I tried a SAAS 140psi oil pressure sensor for E85 in the FRP the other day and it worked.

In regard to needing a sensor over 100psi, my oil pump has a relief spring that is rated from 110psi to 160psi. I also run 40psi or more boost pressure with 60psi base fuel pressure. I would prefer to have a fail-safe that works up to 150psi for those reasons.

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Agree with Puff. 150psi is a better choice to cover all bases.

Here is the Honeywell oil pressure sensor plumbed in for reference. Just common fittings available from any industrial supplier.

Edit: It did effect the reported oil temp. New solution linked here: https://forum.pcmtec.com/topic/1491-micro-controller-using-can-bus-data-for-ancillary-control/?do=findComment&comment=10650

image.png.b847a215041f8788ba8fec98c1c0d1bc.png

Edited by hjtrbo
It didn't work well
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33 minutes ago, hjtrbo said:

@2X044. How quick have you managed to get the engine to shut down? Have you tried instantly I.e. set auF11960 set to 0. Would be very good to have it shut down that quick if fuel or oil pressure drops dangerously low. 

I need to increase the logging speed on some of these parameters to get a more accurate number, however based on one of the logs, The throttle starts being rapidly shut in approximately 0.5 seconds (about how long it takes for the CHT to rise), the injectors are being cut at a similar time and the engine is no longer spinning about 4 seconds later.

What I have found is that auF11960 controls the cylinder shut down, but as soon as the CHT goes above ~125 deg C other parameters are immediately acting to reduce torque to 50% through fuel cuts and throttle position before the cylinder shut-down parameter kicks in.

In general I am hesitant to make any parameter 0s, as this gives no room for electrical noise. Nobody wants there engine to cut-out when they turn on the radio/wipers. In general, I believe there is a reason Ford didn't make all these parameters 0s. I'm cautious about whether I have already gone too far.

 

image.thumb.png.ca2fcc3b1ea88348bdf91a98446d347a.pngat

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54 minutes ago, hjtrbo said:

Agree with Puff. 150psi is a better choice to cover all bases.

Here is the Honeywell oil pressure sensor plumbed in for reference. Just common fittings available from any industrial supplier.

image.thumb.jpeg.a44cfcedd190aaa116a4f4ec8cedbe96.jpeg

 

Must be nice working on a clean motor out of a car. Messing with the EOT and Oil Pressure sensors on my car is a painful experience.

I checked if the number-plate Valdez was available for my car due to the oil leaks...

Do you have experience with the EOT sensor in that location, I suspect it'll be fine but it is away from any "live" flow, might just make it slower to respond. I've left the EOT sensor alone and put the oil pressure sensor in a tee off the turbo feed (AN fittings for braided lines).

Edited by 2X044
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Clean engine is good. Wasn't so clean a while ago, was like yours I imagine, oil leaking out the front cover making a mess of the driveway. 

No experience with EOT. Yes, it will be slower to respond but I don't envisage that causing any issues in this case. The oil and block have a long thermal time constant as it is. 

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  • 3 weeks later...
On 11/28/2022 at 5:49 PM, hjtrbo said:

No experience with EOT. Yes, it will be slower to respond but I don't envisage that causing any issues in this case. The oil and block have a long thermal time constant as it is. 

Way to slow to respond and had a 10deg offset from my previous logs. Calling it a fail. Have relocated to the turbo feed and put temp sensor back to where it was in live oil flow. Just made a npt fitting in the lathe and tigged it onto the banjo nut.

20221217_151527.thumb.jpg.2dc53dbb10362a55e81b1d2613d21438.jpg

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Hey everyone,

I just came across this project and am really impressed with what you guys have managed to do with the factory PCM. I'm keen to get involved with the project once I get up to speed with it. Much more reading to go on my part yet! My day to day is dyno tuning and race care electronics, mostly with standalones, based in NZ. I'm currently looking to get a new shop project car, recently decided on a Barra and just the other day came across PCMTEC and have decided it's definitely the right platform for me!

Here's my 2 cents on the current topic, hopefully it's of use to somone. I use the Honeywell MIP series for every race car we build, measuring oil, fuel and coolant pressure, with great success. But they are sensitive little things that can be prone to failure if they don't get just what they need. The datasheet is a great resource https://www.farnell.com/datasheets/2897784.pdf The big one that kills them is vibration. They don't like to be directly bolted to an engine, they are much more likely to survive when they are remote mounted with a rubber isolated mount.  Haltech do a cheap remote mount kit https://www.haltech.com/product/ht-039103-pressure-sensor-extension-kit/ The other big trap is water getting into the connector causing corrosion. Right angle boots like this are a big help https://msel.co.nz/right-angle-rubber-boot-for-pressure-sensors/

The failure mode on these sensors tends to be intermittent and erratic too which is a big headache. Looking at the data you'll see numbers that don't make sense or brief spikes to 0. It's worth proceeding with caution if you're looking to cut the engine on a street car. I typically will only implement a limiter to ~1500rpm on loss of oil pressure on a street car to allow the driver to limp the car out of the path of potential danger. An emergency over ride switch or button is another option. 90% of the cuts we see are from wiring faults or sensor failures. But the other 10% has saved many race motors!

Also you can get the sensors for a good price with free shipping here :)
https://nz.element14.com/honeywell/mipan2xx100psaax/pressure-transducer-seal-gauge/dp/3364907
Octopart.com is the go to find the best place to buy anything electronic

 

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I've been thinking about this one some more and at the risk of throwing a major spanner in the works, one option that could be worth considering for some people is using a Maxx ecu in a piggyback configuration https://www.maxxecu.com/ (not related to Maxx the workshop). It's a highly customizable ECU with advanced CAN IO configuration. Just about anything you can imagine doing it will do, and if the feature doesn't yet exist they will often write new firmware for you, sometimes within 24 hours. That would give you a lot of the functionality you're looking at implementing without having to go through the long process of bringing new hardware and software to market. Plus you'd get onboard high speed data logging, built in lambda control, multi-level engine protection, ability to control extra injectors, fuel pressure deviation tracking, staged fuel pumps, fully configurable outputs etc etc. There could still be a business case in selling it with a pre-loaded configuration and plug and play harness if you wanted to make a business out of it, implementation is everything.

Please don't get me wrong though, I'm definitely not wanting to derail your project! Just putting some ideas out there from my own background that might be of use to someone. The car world needs more people like you guys thinking of novel solutions to these problems

The Maxx is the path I'm considering going down as I want to experiment with running dual fuel with methanol as the secondary fuel. There's no E85 at the pump here and methanol is cheaper than 98, where as ethanol from a drum is $4 litre

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I'll go you one better. Starts at $88. Write all the custom code you want in easy to learn ladder logic. Analog modules add $130. Industrial rated. Not for running an engine obviously, but for a box that acts on inputs to provide engine safety, this is about as cheap as it gets. 

CLICK PLCs (Stackable Micro Brick) | Programmable Controllers | Products | AutomationDirect

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On 12/18/2022 at 6:27 AM, hjtrbo said:

Way to slow to respond and had a 10deg offset from my previous logs. Calling it a fail. Have relocated to the turbo feed and put temp sensor back to where it was in live oil flow. Just made a npt fitting in the lathe and tigged it onto the banjo nut.

Thanks for sharing your experience, nice for the rest of us to be able to learn the "easy" way.


 

On 12/20/2022 at 4:32 PM, SpeedLabs said:

Hey everyone,

I just came across this project and am really impressed with what you guys have managed to do with the factory PCM. I'm keen to get involved with the project once I get up to speed with it. Much more reading to go on my part yet! My day to day is dyno tuning and race care electronics, mostly with standalones, based in NZ. I'm currently looking to get a new shop project car, recently decided on a Barra and just the other day came across PCMTEC and have decided it's definitely the right platform for me!

Here's my 2 cents on the current topic, hopefully it's of use to somone. I use the Honeywell MIP series for every race car we build, measuring oil, fuel and coolant pressure, with great success. But they are sensitive little things that can be prone to failure if they don't get just what they need. The datasheet is a great resource https://www.farnell.com/datasheets/2897784.pdf The big one that kills them is vibration. They don't like to be directly bolted to an engine, they are much more likely to survive when they are remote mounted with a rubber isolated mount.  Haltech do a cheap remote mount kit https://www.haltech.com/product/ht-039103-pressure-sensor-extension-kit/ The other big trap is water getting into the connector causing corrosion. Right angle boots like this are a big help https://msel.co.nz/right-angle-rubber-boot-for-pressure-sensors/

The failure mode on these sensors tends to be intermittent and erratic too which is a big headache. Looking at the data you'll see numbers that don't make sense or brief spikes to 0. It's worth proceeding with caution if you're looking to cut the engine on a street car. I typically will only implement a limiter to ~1500rpm on loss of oil pressure on a street car to allow the driver to limp the car out of the path of potential danger. An emergency over ride switch or button is another option. 90% of the cuts we see are from wiring faults or sensor failures. But the other 10% has saved many race motors!

Also you can get the sensors for a good price with free shipping here :)
https://nz.element14.com/honeywell/mipan2xx100psaax/pressure-transducer-seal-gauge/dp/3364907
Octopart.com is the go to find the best place to buy anything electronic

 

Thanks for the advice on the Honeywell sensors, I hadn't considered vibration to be an issue for them and was planning on engine mounting the sensors. I might still engine mount for my testing purposes, but it also shines more attention on the need to build a strategy of dealing with component failure.

 

1 hour ago, SpeedLabs said:

I've been thinking about this one some more and at the risk of throwing a major spanner in the works, one option that could be worth considering for some people is using a Maxx ecu in a piggyback configuration https://www.maxxecu.com/ (not related to Maxx the workshop). It's a highly customizable ECU with advanced CAN IO configuration. Just about anything you can imagine doing it will do, and if the feature doesn't yet exist they will often write new firmware for you, sometimes within 24 hours. That would give you a lot of the functionality you're looking at implementing without having to go through the long process of bringing new hardware and software to market. Plus you'd get onboard high speed data logging, built in lambda control, multi-level engine protection, ability to control extra injectors, fuel pressure deviation tracking, staged fuel pumps, fully configurable outputs etc etc. There could still be a business case in selling it with a pre-loaded configuration and plug and play harness if you wanted to make a business out of it, implementation is everything.

Please don't get me wrong though, I'm definitely not wanting to derail your project! Just putting some ideas out there from my own background that might be of use to someone. The car world needs more people like you guys thinking of novel solutions to these problems

The Maxx is the path I'm considering going down as I want to experiment with running dual fuel with methanol as the secondary fuel. There's no E85 at the pump here and methanol is cheaper than 98, where as ethanol from a drum is $4 litre

I agree there are many ways of skinning this cat and the best system for an application will depend on many variables. @Roland@pcmtec suggested early on that the system should be installed quickly and easily without any tools. So far the design on working on will get close to this goal.

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All good. Looking forward to seeing the end result. The can interface is very nice. Would be neat if you could sell me the hardware and open source the code so I can config my own logic. Thinking out loud, I'd like to add in a 20A solid state relay output that can open up the coil and injector power feed in the event of a serious problem. The override switch is a nice idea also. In the event of a 'trip' would be good to have a LED flashing in certain sequences so you know which input or logic combination took it out without having to bust out the laptop. 

 

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Another option that could be worth looking at is using an oil pressure switch that has a higher switching pressure than a typical factory one, say a 15 psi or 20 psi switching point. They're relatively cheap and because they don't have any internal circuitry they're much more robust than the Honeywell sensors and can go straight into the block. A lot of our entry level club race car owners use them as a quick and easy way to get a useful oil pressure warning. Only downside for them is a 20psi switch (light in their case) is active at hot idle.

Or you could get the best of both worlds and use both, the Honeywell sensor and a 20psi switch alongside as a verification check before initiating a limiter or shut down. It's extremely unlikely for the switch to fail compared to the Honeywell sensor, so if the Honeywell shows 0psi and the switch hasn't triggered you would know it's a false alarm. If both go off then it's almost certainly a genuine loss of pressure event. You would need to get some data to find the right combo of pressure and activation engine speed but you get the idea

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For anyone interested. I found my boost control issue. Now I need to decide what I'm going to do about it and how that affects the testing for this system. Thinking of getting a Pulsar turbo as it isn't just the turbine housing but the CHRA is a bit second hand too. I can't see any reference to anything but a 15 psi spring in the Pulsar turbo internal gated options.

 

This is the wastegate fully closed...

20221227_142157.thumb.jpg.4d66931276ee01528b78ac5cc686786c.jpg

 

This is the wastegate fully open.

20221227_142208.thumb.jpg.45f9d3015deefb9b7b02d94ea63bce10.jpg

 

The worst of both worlds, laggy and then not able to control the boost. Funny thing is I can't see how this ever worked, it hasn't failed, with the auto I just didn't notice as much as I do with the manual.

 

Genuine OEM quality.

 

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Get a giant farken bar aka a tire iron and bend the actuator bracket forward with everything still connected and on the car. It'll close the flap and you'll get all that low end power back you forgot about.

If that is too difficult for you, disconnect the actuator rod and use an adjustable spanner where the rod attaches (where your thumb is) to bend that part toward the back of the car. Make sure to remove the E clip before bending, you don't wanna hurt the actuator.

I've done both of these things at different times for different reasons and they both work a treat.

 

Tl;Dr bend it back and send it

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1 hour ago, 2X044 said:

The worst of both worlds, laggy and then not able to control the boost. Funny thing is I can't see how this ever worked, it hasn't failed, with the auto I just didn't notice as much as I do with the manual.

 

 

54 minutes ago, Puffwagon said:

bend it back and send it

 

Might as well port it while you're in there :)

 

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  • 4 months later...

Hi all, sorry for being a phantom. Since I last was here I started a company, rolled that into another company and more. Good news though, I've finally got some time to scratch myself so I have dusted off this project.

I'm thinking through the closed loop boost control and to fully mimic the factory system I need the following inputs:

  • RPM (CAN packet 0x207)
  • TPS (CAN packet 0x207)
  • EngineCoolantTemp (CAN packet 0x427)
  • MAP (CAN packet ???)
  • Manifold Charge Temp (CAN packet ???)
  • ?

I can't see where the MAP and Intake Air Temp is available via CAN without sending 0x7E0 requests. Any ideas?

Do tuners retain the manifold air temperature table or just simplify this? I can't see how it can be retained without an OEM lab.

Cheers!

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On another thing, I fixed my boost creep problem but I don't fully understand how.

I was running the F6 tune but had retained the standard XR6T boost maps. I changed to a turbosmart actuator and still had the issue and would see 12psi and boost cut. Putting the full F6 tune I never see boost creep.

Not sure how the same turbo can creep on one tune to 12psi and not on another (holds steady at 7-10psi) when the only change was to the boost maps. Only thing I can think is that the boost maps caused a feedback to the spark timing...

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  • 3 weeks later...

I found a good use of the time I spend sitting outside my daughters dancing lessons. Only slightly anti-social...

 

Spoofing the engine oil temperature sensor, I can implement a rev limiter as shown in the screenshot below. I was only revving to 1800 before bringing in the limiter to 1500 so it isn't exactly obvious, I'll do a more severe test tomorrow. It didn't feel like a hard limiter though, will have to look into how it is doing the limiting.

 

With this we can implement either an engine shutdown and/or a limiter. From a safety perspective (human safety not engine) I prefer the rev limiter to the shutdown.

 

image.thumb.png.482fcb561651028cdb1324b53a3e0eca.png

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The parts arrived today to snoop on the boost control solenoid valve. I also have all the parts for the final oil/fuel pressure measurement system. Once I have tested both of those I will finalise a prototype PCB that will have all the current I/O.

 

I have also changed the micro-controller to the ESP32-S3 which has both BLE and WiFi.

 

Regarding boost control, I can still not see a way of fully mimicing the factory closed loop system but the open loop system that the system should be able to do straight off includes adjustments or completely separate maps for the following:

RPM

Selected Gear

Throttle Position

Wheel slip???

 

It is also possible to have many more points in the maps (say every 250 rpm).

Any thoughts on whether an open loop boost control system with this functionality would be wanted?

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You gotta send the tmap temp high to run the lower (hottest) line of the stock desired boost table. This is the part of the table that would send it back to gate pressure due to high iat's. Most people wouldn't run max boost in 6th gear so the same principle can be used with boost by gear. Ask Rolls or someone if the tmap switchover will override this.

To have it drop to gate pressure in closed loop, you need to send a boost pressure signal that is higher than the desired boost setting but lower than the overboost setting. It is about 2psi over desired boost stock and will be adjusted to perhaps 5 psi when tuned. This would involve the tuner setting it up as it wouldn't be as simple as toggling a switch. As long as you send the right boost pressure signal it will go back to minimum wgdc, which is 0% stock, but may be higher with other setups. I can't think of anything offhand that would drop it to gate with a simple bit flip but there may be something.

The stock boost control is great and an aftermarket system can't match it as far as I've seen. This is not the case for na+t vehicles so may have some merit there.

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I'm sure that I could spoof the IAT sensor using the same technique as the CHT and EOT but I wasn't sure it was necessary. I would think bringing in a low rev limiter would do a pretty good job of killing the boost. If you are making significant boost by 1500 rpm you need a bigger turbo.

 

I'm mindful that there are a lot of wiring that is being introduced. Listed:

  • Cable to the CHT sensor
  • Cable to the EOT sensor
  • Cable to the Boost Control solenoid
  • Cable to the Fuel Pressure Sensor
  • Cable to the Oil Pressure Sensor

If I keep adding more it will be another loom. I'm already thinking that I need to run one large cable (20+ cores) through the firewall before breaking it into the separate cables. Easy enough to get it through the clutch line grommet (especially for an auto).

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