Check engine light?!? Need some help.

[jackmac]

Hi guys,
Not quite sure what the problem is....but since last Thursday after Larry manually turned down the boost for my turbo (by adjusting the wastegate), the check engine light signal comes on after long drives (~30-40 mintues). And when this happens, my idle fluctuates back and forth, and the whole car seems to be "choking," or rather hesitant. However, after I reset my ecu (pull out the 7.5 from the fuse box), the engine light goes away, and the car goes back to normal.
I suspect that it might be something wrong with my 02 sensor....but not quite positive. Larry replaced an aftermarket 02 sensor when I first got my turbo months ago....Not sure if it is just defective or burned.....what might be the problem? Thanks.
JACK

 

[KODIAC]

what CEL code are you getting??

may help solve your problem...

Originally posted by jackmac:
Hi guys,
Not quite sure what the problem is....but since last Thursday after Larry manually turned down the boost for my turbo (by adjusting the wastegate), the check engine light signal comes on after long drives (~30-40 mintues). And when this happens, my idle fluctuates back and forth, and the whole car seems to be "choking," or rather hesitant. However, after I reset my ecu (pull out the 7.5 from the fuse box), the engine light goes away, and the car goes back to normal.
I suspect that it might be something wrong with my 02 sensor....but not quite positive. Larry replaced an aftermarket 02 sensor when I first got my turbo months ago....Not sure if it is just defective or burned.....what might be the problem? Thanks.
JACK

hmmm..... hunting idle.... on your setup, how is the fuel system managed? is it tuneable? when he lowered the boost, did he bother to tweak the table? doubt this would be it, but a thought.... more likely, it may just be the idler screw adjustment, i know that sometimes over the years, a minor adjustment may be needed here, could be a coincedence(sp i know....) reason i ask about the tuning tho, is if you have larger injectors, this can lead to a problem cause the injector will let more fuel out over stock injectors at same pulse duration... hence needing to retune... just a thought...

If you know how to adjust your wastegate, try setting it back, and see if the idle hunting goes away... Just a thought... it might work...



[This message has been edited by KODIAC (edited 19 December 2002).]

 

[jackmac]

Hey Kodaic,
Thanks for your input, I will definately look into that....however, my idle only becomes rough when the check engine light comes on. How bout the 02 sensors? Do you think this might be a possible cause? Thanks.
JACK

 

[Lud]

What is the trouble code? I think you should check that first! http://www.nsxprime.com/codes.pdf

 

[KODIAC]

Originally posted by jackmac:
Hey Kodaic,
Thanks for your input, I will definately look into that....however, my idle only becomes rough when the check engine light comes on. How bout the 02 sensors? Do you think this might be a possible cause? Thanks.
JACK

again, as i stated to begin, whats the CEL code? this will help you figure out what the problem is... otherwise we're just shooting in the dark....

Have you pulled codes before? i really think that the code will help ya with this,

let us know what code your gettin, and ill try to help ya, its probably just somethin simple...

 

[jackmac]

Guys,
Thanks for the info. I run the test and see what is the code....thx once again.
JACK

 

[Roadrunner]

Jack, for info any time you trip that trouble light your engine goes into a default mode which causes the car to run rich and your idle goes nuts.
If you notice how the cars operation changes after the code light is thrown.
E-mail me direct if you want more info.

 

[kpond]

Roadrunner,

My experience is that the engine will not automatically go into "limp mode" unless it experiences a failure from a critical sensor - usually relating to a/f management. A bad MAP value, bad O2 sensor, etc may cause limp mode. However, numerous other fault codes will simply trigger the CEL but the car will remain in a "normal", very driveable mode.

 

[KODIAC]

Originally posted by kpond:
Roadrunner,

My experience is that the engine will not automatically go into "limp mode" unless it experiences a failure from a critical sensor - usually relating to a/f management. A bad MAP value, bad O2 sensor, etc may cause limp mode. However, numerous other fault codes will simply trigger the CEL but the car will remain in a "normal", very driveable mode.

I will second this fact, not all CEL will revert to limp mode...

Let us know what the code is...