So for the fourth time, my car has gone into limp mode after doing moderate to hard roll ons. The very strange part is that the engine light does no come on and it does not throw any codes after it goes into limp mode.

My car has gone into limp mode in the past BUT it always would throw a P1508 code when it did.

Has anybody ever had their car go into limp mode without throwing any codes?

 

Clean maf sensor or buy a new one. Possible boost leak.

 

+1 check your boost hose connections.

 

Thanks for your input....No boostleaks and I have a mafless tune

 

Thanks but there is no boost leaks(checked many times) and no MAF because I have a Mafless tune. When the care goes into Limp mode I simply turn the car off and restart it immediately and it is fine after that, like nothing ever happened or until it goes into limp mode if I do hi load roll ons again. I've actually done this while coasting on the highway after the car went into limp mode. It is literally a matter of turning they key to the off position and starting it back up. I takes about 2 seconds.

 

Seems like a boost deviation issue. High load, high boost request too early on, boost passes the threshold by X amount (spike), and n75 duty cycle reverts to zero, aka, limp mode. Tweaking of the n75 duty cycle can cure this, but as to why it's not throwing a code, I couldn't help you there.
Get some logs and post them up, including requested boost, actual boost and wastegate duty cycle, load, throttle position...

 

I don't have a Durametric. I'll have to check if my COBB Access Port can log those.

Thanks. Where in Montreal are you? I grew up in Terrebonne but have been living in the Boston area for the past 24 years.

 

Ahh! my business is in Outremont, but I actually live in Laval.

 

You need to do another boost leak or replace maf sensor.

 

OK...I think you misunderstood,

1. I've done many boost leak test and I have no leaks...I've done them from the Y pipe and also from the Turbos. No leaks.
2. There is no MAF to replace as there is no MAF on the car. It has been removed/disconected because I have a MAFLESS tune.(a tune that does not use a MAF)
3. Simply shutting the car off and restarting it return things to normal.

Thanks for your input

 

Sorry i keep putting maf in there. When this happened to me i had a boost leak. Thats the sign of a boost leak. No codes and limp = leak.

 

No worries...Unfortunately it's not a boost leak, I wish it was a simple as a boost leak. Thanks again.

 

How much psi are u going too for boost leak? How long is it holding for? Check your diverters. I have had many people this happened to and turned out to be a small leak. Diverters ans intake plenum. Start getting dirty.

 

I do the tests at 25 psi. When I do the test from the Y pipe, it holds pressure for ever(long time). When I do the test from the Tubos it goes down slowly(Blow by). I can hear the air deep in the bowels of the engine, exhaust and oil filler tube. I use soapy water to check all the lines.

 

When going fron the turbos there should be losing boost. I just had mine done today and it holds steady.