I've got a stock B18B (OBD2B) in my 97 Civic. The car ran fine, if not a little rich on the stock P75. I now have a Phearable.net P06 chipped with their standard LS map. Car runs great, except ....

When cold, I have a fluctuating idle. It bounces between 1800 and 600. When it drops below 1000, the car sputters, and almost dies, lights dim, that sort of bs. When the car gets to temp, the idle rests neatly at around 800, where it should be.

There were absolutely NO problems with the P75 .....

Any sugguestions?

 

Did you try contacting them for answers? Check your FITV and IAC if you have them.

 

John mentioned the IACV ... but I didn't want to mess with it, because it's not bad when warm, it's perfect. I don't want to expletive up the normal op idle.

 

Cleaning that wont mess anything up. Also if you dont want to fix a possible cause what do you expect them to do?

 

https://honda-tech.com/zerothread?id=886330

This guy has the same problem ....

 

I guess I don't understand the concept of a valve being the problem .... only when the motor is cold..... if something is broken or hindered, it's just that. It doesn't fix itself when the car gets to normal operating temps. If it was the IACV, it would have been a problem with my OBD2 P75.

 

True, send the ecu back and ask them to play with the IAC more. What program did they chip with?

 

is your purge solenoid still hooked up. I unhooked the line fromt he intake manifold to the pruge soleniod and it smoothed out cold idle a bit since obI doesnt "understand' it i guess

 

I'm going to try the Evap trick. My friend said something about it, but I was wary of just shucking sensors off my car

 

mine still sits on the fuel rail, the plug is plugged in, i just capped the nippleon the mani and on the purge solenoid and let the other line run to the charcol canister

 

I had a friend hat had the same problem, his old ecu ran fine but his new one did that, he put his stock back in and it still did it. When he put the new ecu it (new one) had a bent pin, which screwed up the harness, fixed it and was fine, it just bibnt occure to him to look. I don't know why his idle surged on a cold motor but it did. Its worth looking.

 

Unplugging the Evap sensor seemed to work. I'll know better tomorrow when the car is actually "cold"