Cold start refinement

[apoc]

Hi all,

Any recommendations on how to refine cold start? My Barra swapped GQ Patrol runs and drives amazingly when warmed up, and starts really easily (even cold), but the power delivery is pretty shocking until it does warm up. Doesn't miss or pop, just way down on power and not smooth. I don't remember any BA/BF falcons being like this.

Any tips / tricks to making it run *not* like a bag of dics on cold start?

Cheers.

Specs: GQ Patrol, BA eGas i6 (10.7:1), FG plastic inlet manifold, underdrives, modified hurricane extractors, BF XR6 cams, loom & PCM

Edited October 30, 2018 by apoc

[Roland@pcmtec]

I fixed this on my manual BF (HACCKGA) by fixing all the cold start spark tables

These retard the ignition timing massively on cold start (-5 degrees at idle etc) which causes the car to run terribly for a few minutes to warm the coolant and catalytic converter up.

You can zero these out and then fix the cold start idle targets. They also play with the cam timing at idle when cold as well. You can make the car run the same as hot if you fix all of these tables. 

Remember that it does serve a purpose, the car can take almost 5-10x as long to warm up if you do remove these tables. Eg if you drive straight onto a clear road at 60kph with no load the car will remain well below operating temp for 5+ minutes instead of the 1 minute it would normally take. This means more engine wear as the oil is cold and your emissions are way off target for much longer. Do you care about this? Maybe. Will it pass emissions? Absolutely not.

Personally I left the tables as they are stock, but made them only last for 60 seconds, this means the car gets up to temp quite fast and then immediately runs full spark after this. The car drives much nicer.

[apoc]

Thanks Roland, I'll probably just do similar to what you have done for yours. Faster warm up is great, but when it sacrifices driveability (past a minute or so from dead cold), it's annoying.

Appreciate the reply.

[05ENFORCER]

Hi, I have a vehicle with an interstate tune in it and it has a problem with the cold start.

Basically the colder it is, the worse it is. Starts/cranks fine then slowly over revs until it stalls with malfuctiion light on, restart, MIL goes off but does it again.

Obviously when it is warm, no problem.

I fluffed around in auF0411 reducing the values and ran outta time/temp before I could prove it worked but i thought I might ask for some guidance. 

Would I need to add/decrease fuel also?

Edited February 3 by 05ENFORCER

[hjtrbo]

The commanded spark might nudge you in the right direction. If it's pulling a fair bit of timing out you can look at auF0032 etc. Another 1 to check for crank to run transition is auF1721 hasn't got something stupid in it. 

 

Edited February 3 by hjtrbo

[05ENFORCER]

auF0032 is Idle Airflow in Park/Neutral (RPM) ???

auF1721 is 10 degrees from 20 to 200deg F, std I believe

Edited February 3 by 05ENFORCER

[hjtrbo]

auF0032 yes

auF1721, good.

To be honest I'm just spit balling trying to help.

Another good one is auF0210.

Is the dtc it throws with the mil noteworthy?

[Puffwagon]

I'll make a post tomorrow about the various parameters you need to look at for hot and cold starting. I can get my big cam barra starting first crank on e85 whether 0 degree winter morning or 40c summer day.

If you post your tune I'll have a look through it and see where it likely needs attention.

[05ENFORCER]

@hjtrbo, throttle body position I think

@Puffwagon, I will have another read of your posts tonight, will post tune tomorrow if I can remeber how

[05ENFORCER]

tune file, hopefully

HAFI3GB03022024modauf0411.tec

Edited February 3 by 05ENFORCER

[Puffwagon]

Yeah can't look tonight but will tomorrow for sure.

[hjtrbo]

puff is the man, you'll be in good hands.

But auF0260 Torque module switch. First time I've seen that turned off. You tried turning that back on?

[05ENFORCER]

Haven't really delved into it, just concentrating on the cold start problem atm mate. It did 615 rwhp on the dyno, so it's not too bad.

Edited February 3 by 05ENFORCER

[hjtrbo]

Idle has some torque based parameters. Was just a thought.

Nothing else really sticks out apart from that etc table you mentioned at the start. Be good to turn your over boost protection on.

Till the puffman gets a look hey. 

[05ENFORCER]

Cheers hjtrbo, i am only a dabbler mate, it takes a while for me to do this stuff, all not for profit, well maybe beers,  and certainly not a tuner or business inclined!

[05ENFORCER]

Now looking at auF0173 and auF16229

[hjtrbo]

What are the mods to it? 

[05ENFORCER]

1000cc KPM inj, GT500 TB, IC, Underdrive and exhaust AFAIK. I think the prob is ETC

Edited February 4 by 05ENFORCER

[hjtrbo]

yeah, that t/b will need setting up. I can't help with that 😔

Go stock t/b it'll probably fire right up. That's not the idea though, I get it.

[Puffwagon]

I had a look at the tune and nothing looks way off. When a car will start when hot but not when cold or vice versa, the problem is the cranking afr is wrong. Usually when a car is cold it will start ok even when extremely rich, the issue is usually not enough fuel when cranking. You can change the cranking afr by either adding more fuel or changing how much the throttle is open. More fuel means more rich and more throttle means more lean. You can also remove fuel and close the throttle, you need to take note of how much the revs jump up when it first fires up. Assuming the fueling is correct, a big jump means too much throttle opening and a stumbling start means not enough.

In this case we don't know whether the fuel auf0180 is correct or if auf0411 is correct. I would increase the numbers in auf0411 that have been modified, I would start by doubling them. It's easier to have too much throttle opening and adjust the fuel, than have not enough throttle opening and nothing ever happening cos there's not enough air.

A good way to test if there is not enough cranking fuel is to crank the car for 1 second then stop, repeat this several times and if there's some life then it's fair to assume the cranking fuel needs increasing. This is done by lowering the values in auf0180, I would change them by 0.1 at a time until there's some life when cranking, then adjust it by 0.05 to get it closer. Conversely if you can get it to start better by using a bit of throttle pedal then it's safe to say you either need more cranking throttle opening or less cranking fuel. If adding fuel all the way down to 0.5 lambda makes no difference, go the other way, it's trial and error.

These are the only 2 things I would be changing to get the car started in this case. There are other fuel things to change but not needed atm. Leave the spark alone, 10 degrees is fine.

Another helpful thing to keep a car running after startup is an idle startup adder auF0028. It will help to keep the car running for the first 30 seconds or so when it is stone cold and not wanting to have a low idle.

Long story short, get more throttle opening when cranking to rule out a lack of airflow when cranking, do some cranking fuel testing to see what the car might need, adjust the cranking fuel most likely richer but perhaps leaner.

Edited February 4 by Puffwagon

[05ENFORCER]

I'll see if I can take a video of the start up, it might paint a better picture.

[Puffwagon]

It's one of those things that you have to spend the time getting right. It'll seem like nothing works for a while but it does come good when the tune is right. It might take a week of cold start adjusting if it's way off.

Pretty sure I was getting etc errors when I changed the throttle opening too much. It was a while ago so it's not crystal clear anymore lol

[05ENFORCER]

https://drive.google.com/file/d/1tv7kxJl37MfGbEI1DTtf7Rx_1FHt04qu/view?usp=sharing

[05ENFORCER]

Cheers bro, It will take some time but I need to go to work for a week, so I'll research and come back to it. The car is a 2016 FGX Sprint btw

Thanks for your help so far.

Edited February 4 by 05ENFORCER

[Puffwagon]

I'm not at the desktop now but I'll compare your hot start part of the tune with the video when I get a chance tomorrow. Pretty sure there was a 400rpm adder in there but can't remember which one it was off the top of my head. I only really looked at why it wouldn't cold start, I'll have another look regarding the raised rpm post start.

[05ENFORCER]

37 minutes ago, Puffwagon said:

I'm not at the desktop now but I'll compare your hot start part of the tune with the video when I get a chance tomorrow. Pretty sure there was a 400rpm adder in there but can't remember which one it was off the top of my head. I only really looked at why it wouldn't cold start, I'll have another look regarding the raised rpm post start.

Thanks mate.

Hot start no problem, cold start, high revs and then shutdown with dtc, as in video, no dtc logged, restart, 2-3 goes and she is away.

Throttle response is superb throughout the rev range but you will notice there is some damping in the early throttle actuation (auF0084/0084) as apparently, this car wants to light up the rears with the higher diff ratio and used to buck at the touch of the throttle. otherwise it is very strong and predictable.

[Puffwagon]

Ok I didn't look at the temp gauge and I didn't read the first post properly. I can see it starts fine but then stalls after a short amount of time. I would start by making all of auF0028 zero, this should lower the rpm when it starts and might be enough to stop it having a dtc.

The reason it will want to light up the rears is because the torque control module is switched off. Switch it back on and the tip in retard part of the tune will work, this removes timing so the car doesn't go nuts every time you touch the throttle.

[05ENFORCER]

Thank You for the info, I will attempt to do this next week. Thanks again fellas.

[Puffwagon]

No worries, haha next time I'll actually read and remember the post properly

[05ENFORCER]

How embarrasing, a simple zeroing of auF0028 and wella, problem solved.

I guess I was looking for the problem in the twin throttle body, when it was staring me in the face.

Cheers fellas, much appreciated.

[Puffwagon]

Glad to hear it was a simple fix.

[Roland@pcmtec]

On 2/13/2024 at 7:32 PM, 05ENFORCER said:

How embarrasing, a simple zeroing of auF0028 and wella, problem solved.

I guess I was looking for the problem in the twin throttle body, when it was staring me in the face.

Cheers fellas, much appreciated.

You often see the same error with large cams or intake leaks (due to the extra airflow at idle) triggering the IPC (basically it thinks there is a post throttle body air leak and shuts the car down to prevent a run away engine).