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Trouble with limp mode around 4000rpm


seanlivingstone
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Hi there.

We recently fitted a new turbo with an external gate. When we run it up on the dyno, we get to about 4500rpm and we get a massive power cut. Once the car is back at idle, it runs extremely rich for a while and then randomly seems to come good. We have everything in open loop and at the moment we are just relying on spring pressure in the waste gate. We're pretty sure it's something to do with boost control... We've logged all torque sources and can't work out what's causing the issue. We've got several fault codes, and spent a few hours trying to figure it out but we are a bit stuck. Oxygen sensor is also currently unplugged. Thanks in advance to anyone that can help. I've uploaded a datalog, the tune, and also a pic of all the fault codes.

Cheers

Sean

IMG_8848.JPG

4.teclog load in.tec

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This looks quite likely to be a mechanical issue.

The throttle is staying wide open and wastegate duty cycle is not changing however your load and map is dropping drastically. You also have a huge boost error implying the PCM is not requesting less boost.

Is your intake piping sucking shut on the compressor intake? This will feel like a fuel cut, it also may stay stuck shut for several seconds.

Is a hose clamp blowing off?

image.thumb.png.fcdd920cd03c1023f579a94a82fda37a.png

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Hi Sean Livingston,

   I have seen this before and I would recommend you fix those fault codes. Don't waste your time until these errors are resolved.

It sounds to me like a wiring issue. Can bus errors like these will cause all sorts of FMEM modes. Given you have fitted a new turbo look for a plug being pulled out or damaged. If the car has a ZF check the round plug on it for a pushed out pin. It is not uncommon for the PCM connectors to come loose as well so try and see if the plug is loose or not locked in. 

You need the CAN bus (OBDII communicates over it as well). Also check auxiliaries like the alternator as the modern ones have a CAN bus signal wire going though them (smart alternator). 

Speed Control command switch high also shows faulty wiring/short in the steering wheel cruise control. This is from the internet:

image.thumb.png.e2fb557413a822a624a33b698ac37286.png

Let us know how you get on.

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Thanks for the swift response guys!

Roland - I reckon you may be onto something here. The intake that we have setup at the moment is only something temporary - the car is booked in early next month to have the entire system done properly. I'm home now, but I will check this out first thing in the morning. I'm suspicious of the hose going between the turbo and air box, I'm thinking that may be our culprit. I've attached a photo so you can see what I mean.

 

Darryl - So sorry, I should have made it clear that this is Nissan Patrol conversion. I would be really surprised if it was a wiring issue, because the only thing that has been altered since the car drove fine is the turbo and intake piping. Still, thank you for taking the time to respond so quickly!

7BF6CE07-C2BC-46D1-96F1-BE3C043C0079.jpg

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17 hours ago, seanlivingstone said:

Thanks for the swift response guys!

Roland - I reckon you may be onto something here. The intake that we have setup at the moment is only something temporary - the car is booked in early next month to have the entire system done properly. I'm home now, but I will check this out first thing in the morning. I'm suspicious of the hose going between the turbo and air box, I'm thinking that may be our culprit. I've attached a photo so you can see what I mean.

 

Darryl - So sorry, I should have made it clear that this is Nissan Patrol conversion. I would be really surprised if it was a wiring issue, because the only thing that has been altered since the car drove fine is the turbo and intake piping. Still, thank you for taking the time to respond so quickly!

7BF6CE07-C2BC-46D1-96F1-BE3C043C0079.jpg

After looking at that photo and Rolls' screenshot. I tend to agree on the basis that it looks like you have a snorkel too, that is going to cause a whole lot of upstream flow restriction (+ airbox + filter) and a large diameter un-reinforced hose will struggle with that, its also got a crease which wont help things.
 

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