ok the car is a 94 civic with h22a swapped into it.

the problem is at idle a cold idle its been running around 15.5 to 1 afr's.
when cruising its been running around 14.7 to 15.0 afr which is fine.

but sometimes at idle it will slowly start to lean out to 16.0 to 1 and then it will missfire and start the process all over. and on a hot day the afr sometimes will dip down into the mid 13's on the afr gauge sitting still idling(completely warmed up)

so im thinking it has to have to do with the fuel system.

it has stock injectors stock filter and a 190lph walboro in-tank pump.
i replaced the fuel filter and it didnt help
could a injector be clogged?
pump going bad?

by the way it is running the stock ecu, and throwing 2 codes one for the egr (because its not there) and one for the o2 heater( i have a plx wideband in it and went by their instructions it will throw a o2 heater code but not affect anything)
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Ummm... Test your fuel pressure. If you have an FPR with the guage that would do I guess (if its a good aftermarket fpr)

You know for a fact that that the O2 Heater code isn't saying that somethings incorrect?

I would suggest if you have a standard o2 sensor maybe remove your wideband and see if that changes things.

I don't think your egr will cause whats going on, but the o2 however might.

Last option is to try getting tuned. Might be a bit of money but a tune will allow your h22vtec to perform at its best.

 

just asking but did u pull the stock o2 sensor out and just running the wideband? If so ur cars in Limp mode. Not calling anyone a newb but I did that myself when i first started messing with this stuff.

 

the plx widebands can be used to run wideband and work as your stock o2 sensor.

it says directly in the plx instructions they way you wire it up that it will lie to the ecu basically and it will throw a code but not affect anything.

i have had the wideband in for almost a year and if it was gonna cause issues it would have done so from the beginning not randomly a year ago

but thanks for any input.

its the stock fpr on it and i have a gauge at the fuel filter and it is reading accurately a little above 30 psi at idle.

 

Which stock ecu you using anyway? the p13 ecu right?

 

Well, if your a/f ratio is dipping down into 13-1, then it's running rich. Without the egr there, it's gonna set a code and cause a misfire, because it has a connector for the egr, correct?

 

yes im using the stock p13 ecu.

yes without the egr their it will throw a code, no it wont cause a misfire.

go to thinking also (which i might be looking into this way to much) it only does it when its in closed loop, never misfires when im at WOT, maybe a sensor going bad im gonna recheck the codes again and post up the results.

keep the input up guys, thanks for any help or suggestions

 

When you're at WOT the EGR is not used. It's only used for emissions at idle.

 

i know it isnt used when in WOT but i have the car for over a year now it would have used the egr for emission just as much as when i first swapped the engine in as it would now. so i dont understand how the problem could have just shown up

 

bump for some more input

 

Most wideband O2 controllers are programmable for the narrowband output. You can "set" where you want the engine to run. While 15:1 will give better mileage, from what I have read, most engines need closer to 13.5 up to 14.1:1 so that the catalytic converter will work. Looking on monstersquirt.com, there is mention that high 12's will give peak power while 15:1 or greater will cause the head temperature to climb drastically.

You might look at adjusting your narrowband emulation set point a bit lower.