Hey Guys, Im new to the posting so bare with me. I have gotten alot of info from reading these forums but cant figure this one out. I have a 97 1.8, chipped, 710N, n75J, that is in "linp mode" and I cant figure out what is wrong. I have tried swapping out the 710, also put back the stock n75, also switched the maf and checked all hoses for leaks but have not been able to get out of limp. I actually swapped the turbo out the other day hoping it was a wastgate or turbo problem but no changes. Does anyone have any other ideas what I should check?

I have scanned it several times and never have come up with any codes. I have read that a bad o2 sensor can trigger limp mode but wouldnt I get a code for that?

PLEASE HELP!!!!

 

Do you have a boost gauge? What chip do you have? When did the problems start to occur?

From my experience, limp mode is usually caused by a boost leak that messes with the air/fuel ratios. You might want to check for boost leaks, there is a fairly easy and effective method that involves a tennis ball on AudiDIY.com. Just make sure you dont over-pressurize the system.

 

well its possible that it could be boost problems, not limp mode. changing out the turbo is a start, but i would have checked other things first like boost leaks. what you need to do is get a boost guage and post your readings. since there arent any codes being pulled it is most likely boost problems and not in limp mode. however, to make positive you could reset your ecu by disconnecting your negative battery terminal for a minute or two. only do this if you have an aftermarket radio or you know your radio code though. if you pull the terminal, you will have to realign your throttle body too by turning the key to "on" position for 5 minutes after reconnecting the terminal.

 

Yes, I have a boost gauge and am only boosting at 5. I was peaking at 20 and holding around 18 then it all of a sudden went into limp mode and I have not been able to get it out of.

I am running speedtuning software which was fine for the past year.

I have checked several times for any broken hoses or boost leaks without any luck.

 

I was trying to think of whether i disconnected the battery since the problem but cant remember so, I will try to reset the ecu first and reconfigure the valve body.

 

do the tennis ball method of checking for boost leaks. if you did have one i would assume it would farely large if your loosing that much boost. if you cant find any bigger than a pin hole, my first bet would be a problem with the software. contact speedtuning and they should be able to reflash the ecu for free, although you might have to pay shipping. if speedtuning came with the car when you purchased it, you better hope they have your vin on file.

 

Thanks for all the input guys. I reset the ECU and TB and still had the problems. I hooked up a pressurized smoke machine at the MAF to look for leaks and found the breather tube under the intake had a huge crack. I ordered one and will be putting it in tomorrow. After reading several posts I am wondering if I am right in saying that that could definately be my boost problem. I may not have been in limp mode but just getting 5 psi of boost, Am I right??

 

There's a great chance that you found the source of your boost problem.

I wouldnt worry about whether or not it was in limp mode or was just bleeding boost.

 

Unfortunately, I replaced the breather and am still having the same problem. Any suggestions on what to check next?? Also, If I hook up a smoke machine from the MAF sensor hose will this show me a vacuum leak or is there a better hose to go through??

 

make sure you clear the codes

take the tip off the airbox and use that, it should work fine, i dont know what you mean by "better hose"