Ok, where to start? So the car is 96 civic coupe ex 5spd. The motor is a ls/v running on a stock p28 ecu. Started last night that car was in limp mode (3500rpm rev limit) turned the car off and on a few times and then it would run fine until I left work tonight about 30 mins ago. Has trouble starting as it's either getting too much or not enough fuel to start. On the 2nd try it starts up and has a code and runs rich. Also earlier the cel light would flicker but then stay off and the engine would run great. Also note that when the cel light comes on, it goes away once you turn the car off and back to the on position. Any thoughts or suggestions are welcome, please try and help me out. Thanks

 

Have you tried pulling codes?

Really at this point it's throwing darts blind folded.

I do know O2 sensors plays a role in fuel trim. Primarily the upstream O2 sensor. But then again, I have a feeling there are other things that could provide similar symptoms.

 

Ya know, common sense would say that if the CEL is on, you pull the codes.

 

stock p28 on a ls/v? there's your problem.

 

Why do people keep insisting on doing this? Running a single cam ECU on a DOHC engine? On top of that a Frankensteined engine? I've read the "Reliable LS/VTEC" thread and no where does it say to run a stock P28 ECU. Lord knows how the rest of it was put together.

Pull the codes while the engine is still running. Too much guessing going on in your first post.

 

Because every time I try to pull a code it goes away. It acts as of a plug is losing connection. Just forget it

 

It goes away while the engine is running?

 

What are u using to pull codes? Paper clip? scan tool?

 

Paper clip. The code comes on once the car starts. I turn off the car to pull codes with the key in the on position and the code goes away

 

I think I said plainly, "While the engine is running." That means "Do not turn off the car."

 

I plainly didn't read your comment very well. Anyways I just came out here to check the harness and started the car. No trouble starting and no cel. And for the record a p28 was the cheapest I could get at the time. I'm going to be getting a chip from phearable soon enough

 

Hrmmm. When the CEL pops, pull over and jump the service connector. Also you have yet to explain why you are running the wrong ECU on the engine or even what your LS/V consists of.

 

It basically a stock ls/v with mild head work. I wanted to run an obd1 dohc vtec ecu but I've honestly been out of this for a while so I'm rusty on the ecu codes that ran dohc vtec obd1 motors, my bad. I understand I'm being judged right now

 

Op, id start at finding a vtec dohc ecu. Gsr p72 or si p2t. Regardless of your reasoning for running p28, its not doing you any good.. get the right ecu or chip the ecu and do a tune.

 

There is no such thing.

 

Ok

 

When the CEL turns on, you need to leave the engine running when you jump the service connector to pull the codes.

...and you also need the correct ECU for the engine, as already mentioned.

 

Ls/v's, b20/v's aren't stock manufactured engines so there isn't a "correct" ecu. As I stated I'm having it tuned, wow