Check Engine 1-4 light issue

Need to read the codes. This type of error seems unusual.

 

For the check engine light to come on we would need to know if the whole exhaust is stock or what exact configuration you have for
Headers
Bypass system
Cats
Muffler
We would also assume your car is for USA not euro

 

Perhaps something not put back in the right place or loose connections. Hard to say until we get some codes.

What sensors and devices are used when the engine is warmed up and idling? Idle air controller, O2 sensors, knock sensor, throttle position sensor (sensing idle), MAF ....?

Any excess fuel coming out the tailpipes after warmup during idle?
Do you have regular air filters or oiled ones?

Some sensor might be slightly out of tolerance, but produces a slightly better reading above idle. How hard is it to swap and/or clean the MAFs on a 2.7 car?

 

My F355 Challenge behaves that way too except both CHECK ENGINE 1-4 and CHECK ENGINE 5-8 lights illuminate when the car idles for ~2 minutes and while I'm in the garage area moving slowly. They go out when I get up to speed on the track. They come back on in situations where after I've pitted in I have to drive a distance at slow speeds until I reach my garage spot.

My car has gutted catalytic converters and a Challenge exhaust (no bypass on those). It behaved the same way with the stock headers that preceded its current Tubi headers.

 

Check the codes. If it only comes on a idle and you have a lambda code (1211, 1212) check for a vacuum leak or misfire. Or it could just be a old O2 sensor.

Oil pressure 65-70 at idle is normal if the oil is cold. If the oil is up to temperature, it is excessive. That may indicate a bad oil pressure sensor. Normal oil pressure at idle with hot oil is around the first or second mark on the gauge. This would be typical with the oil temp at about 170*F

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Two separate issues. Oil pressure has nothing to do with your codes.

 

Hi Tom,

The check engine lights always come one within a few seconds of each other and extinguish within a few seconds of each other. With the way my Challenge car's exhaust is set up and the tune that it had yielding a slightly rich mixture at idle, we figure this is normal behavior. We never checked for codes. Indeed some other F355 Challenge cars I know do the same thing.

Below are dyno graphs which show the air/fuel mixture.

Barry


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Barry, not sure why you would suggest that a stock 2.7 355 would behave like a challenge car. My car is a 95 and any CELs and codes have been due to issues that needed to be addressed.

For the OP. I've attached a pdf on how to read the codes. Note that you may have the hold the button down a little longer (few seconds) that indicated.

 

I didn't suggest that at all, John. I specifically mentioned my car has gutted catalytic converters and a Challenge exhaust. I also mentioned the tune done in 2013. As a result, I indicated how my check engine lights behave.

Despite the appearing and disappearing check engine lights, my car runs fine. As you mentioned, Tom has to pull some codes to narrow down a possible problem. I simply gave him a few modifications that could yield a check engine light.

 

Can someone please explain to him how to read his codes.
On an obd1 car you can still read codes.
I think it explains that in the owners manual, flashing lights on the ecu’s in the back of the cars or something

 

John I think Barry was suggesting that if some of us want our car to be as fast as his challenge the check engine lights need to flash a bit at idle.
It’s kind of like flashing your lights to pass in Germany I think. I think Ernie has his 348 set up similarly.

all kidding aside since we are all really guessing here I want to suggest his cats are shot and are now straight pipes

 

I posted a pdf with the details of how to read codes and what the codes are.

No cats on a 2.7 car won't cause any CEL issues .

 

Then maybe Tom's air/fuel mixture is too rich at idle. That's what we attribute my check engine light behavior to be caused by. One day I'll have my technicians look for codes but my car runs just fine.

 

Yes, too rich or too lean. That's why I suggested it could be a vacuum leak, or maybe just a marginal O2 sensor. A small vacuum (or even exhaust) leak can cause an apparent lean condition at idle and push fuel trim to the max causing a CEL. As soon as you open the throttle the metered air swamps the leaked air and the CEL goes out. But we need the codes to see if it's related to lambda control.

 

Post the error codes or it did not happen.

 

CODES CODES CODES CODES CODES CODES ....

 

I have experienced a similar situation in my '97 355 spider. many of you have been quite gracious with your time and comments and once I have my reader delivered, I'll get back with those codes. Appreciate all your help !! Cheers, jon