Fuel AFR is driving me nuts

[BotchedNotch]

This is my first post so if this thread is wrong I'd appreciate it if I can get guided instead of chewed..

That being said. I have a couple problems I'm runningn into that I can't find the problem to. I have a 302 swapped 88 notch (original 4cyl)

First problem, when I start the engine (hot or cold start) it'll idle normal 14s-15s... 2 minutes into idle and bank 2 will idle rough and missfire (high 20s) photo attached. And that's ONLY bank 2 because bank 1 will stay 14s 15s upon start. It will do this for about one minute, I haven't timed it but thats my guesstimate.

Second issue, after the rough idle The engine will settle idle at at about 19s - 20s AFR is this normal? now I'm no tuner but shouldn't I see 14s-15s steady at idle? The engine runs and drives good, holds a 16.5 when cruising in both banks. Checked all 8 spark plugs they look decent, they don't look wet or too clean.

*Bonus, when I'm cruising and I release the throttle, while in gear I hear some popping. I'm currently running shorties with catless H pipe. And SLP2 mufflers also smell unburned gas but unsure if it's my fuel system or the exhaust system.


My biggest issue though is the first one. Has anyone else gone through this?

So far I've swapped to BBK fuel pressure gauge, set at 39psi. And ev6 19# injectors. Still running 4 cyl fuel lines. Going to do AN fuel line swap tomorrow.

 

[Noobz347]

First, pull OBD codes.

Thoughts:

Injectors are wired incorrectly or out of order.
Bad or poor injector ground.
Bad or poor ECU ground.
Bad or missing O2 sensors.
Incorrectly wired/routed spark plug wires.

You eluded to the ability to read AFR on the individual left and right banks. Does this mean that you have replaced your narrow band sensors with wideband sensors? If so, what are you using to convert the O2 sensor signal for the EEC?

 

[BotchedNotch]

First, pull OBD codes.

Thoughts:

Injectors are wired incorrectly or out of order.
Bad or poor injector ground.
Bad or poor ECU ground.
Bad or missing O2 sensors.
Incorrectly wired/routed spark plug wires.

You eluded to the ability to read AFR on the individual left and right banks. Does this mean that you have replaced your narrow band sensors with wideband sensors? If so, what are you using to convert the O2 sensor signal for the EEC?

I did, i repaced my narrow band for wideband sensors. I have (AEM xseries) tapped my white analog+ signal from the gauge to pins #43 & 29.. one per gauge obviously.. I'll double check my ecu ground and injectors ground tomorrow.

 

[Noobz347]

I did, i repaced my narrow band for wideband sensors. I have (AEM xseries) tapped my white analog+ signal from the gauge to pins #43 & 29.. one per gauge obviously.. I'll double check my ecu ground and injectors ground tomorrow.

Check to make sure the correct connector to the correct injector too.

Thought process: If one or more are swapped and you have a bank going [lean] after enrichment ends... You follow?

Are the injectors new? Have they ever been flow tested?

 

[CAMTWO1070]

If I read what you wrote correctly you say you totally eliminated the narrowband 02 sensors?

How about the EGR?..If you totally eliminated that too but didnt disable that or the thermactor in the ECU removing the EGR without putting the resistors or turning it off the timing will run locked out...



If you did totally eliminate the narrowband 02 sensors Id still run the narrowband o2 sensors plus add a couple no weld sensor bungs with bandclamp for the wideband to get a way better reading aswell as correction.

When I installed my wideband I had to do whats called a "FREE AIR" calibration to get my AEM wideband to read right..




Other factors could be a faulty coolant temp sensor , wrong MAF sensor . faulty aircharge temp sensor ,even a faulty TPS sensor or adding a vacuum line to the BAP and turning it into a MAP is also bad...


Having a way to pull a logfile definately helps and with your wideband you can datalog seperately but will need extra wiring done ...




The only other thing I can think of is the wiring for your TFI module and the type of module youre running and whether you have a 22kohm resistor on the IDM circuit wire coming from the ECU plug if its a 5 speed manual since you stated the car used to be a 4 cylinder?





Good Luck