not getting closed loop to work. Need ideas fellas!

[booested4door]

Hello again guys! Ive been working with Marc at efi express on tuning my car. Were on m232 software and cant seem to get closed loop to function. Im stuck rich at idle and low load cruising. MIL comes on at idle and same low load. Replaced all studs pre 02 looking for air leaks, new o2 didnt change anything. Meac thinks car has a misfire, but hes across the country and i dont think it is. If so, its super minute. New plugs will be here this week too. Anyone have thoughts on what could cause it to not want to go into closed loop?

[Crasher]

What is the Lambda voltage at idle?

[tekstil]

If MIL lights up then check with VCDS what's the issue. Did you get Winlog working? Check AFR_REQ and ECT values, might be that your ECT sensor is faulty and ECU thinks it's cold thus never goes into closed loop and keeps on enriching mixture by reading warmup enrichment tables. AFR_REQ fluctuating up and down - it's in closed loop, fixed value - open loop.

[booested4door]

hello! i did get winlog working. He orginally sent me a file the wasnt m232. now all set up with it. MIL is code 00537- lamda regulation 08-00 control limit surpassed. ECT says 93 on my last outing with winlog running. Didnt think about the coolant sensor... will investigate! And AFR_REQ values dont flutuate.. so stuck in open loop and cant figure out why

[booested4door]

What is the Lambda voltage at idle?

I havent tested this, I will now though...

[tekstil]

What's the AFR_REQ value with ECT at 90+ degrees in idle and on cruise?

[booested4door]

i have two different chips here from marc that are closed loop..one rides at 10.59 at idle and light cruise with 93 ect. And the other rides at 11.69 at idle and cruise with a 93 ect again. Both were read on days above 90 degrees. Ect tests at 2800 ish ohms across its pins. seems like the ect value isnt changing on winlog. Ill go for a drive later to verify. didnt notice that wasnt moving. Have been focusing on afr..

[tekstil]

Do a cold start and verify that the ECT climbs up as it should, from the 10-20 degrees or whatever the ambient currently is all the way to 90+ degrees of warm engine. 10.59 and 11.69 are the values displayed by the AFR_REQ? What's the actual AFR with wideband at that moment? What is LOAD value at warm idle? It's all guesswork from here, without looking at the file in Tunerpro. Could be list of things like injector constant, deadtimes, fuel enrichment table, lambda load threshold set wrong but I doubt that's the case. Might be some sort of hardware problem related to lambda sensor, wiring etc.

[booested4door]

Will hook the wideband back up, but only have one o2 bung. Wideband will be simulated narrowband to Ecu. But will get its output for ya.
Coolant temp sensor does raise as car warms up to 91-93c. Continuity tested o2 wire to Ecu, all good. But it did have 1.5 ohm resistance. New plugs and a brand new o2 sensor today also. No change.

[tekstil]

Single O2 bung will be a bit problematic since you can't compare AFR_REQ to actual AFR. Strongly suggest you to drill a hole and weld another bung into downpipe. Simulated narrowband won't work properly if at all, it has been discussed before. You are creating more headaches for yourself if you are trying this route. Best way is to have 2 bungs, let the motronic have its OEM sensor for closed loop control and second one for your wideband to get actual AFR reading next to motronic's AFR_REQ so it's easy and sensible to tune, whether on street or dyno.

[ottawa coupe]

Simulated narrowband won't work properly if at all, it has been discussed before.

Is that so? Hmmmm, i am having the same issue tho my afrs aren't toooooo terrible (14.2 afr when i figure i should be 14.7).

I hope i haven't been too efficient and thrown out the bung that came with my wbo2 lol.

You'd think that if the simulated o2 signal was "wrong", the ecu would flag a code?? But maybe it just wasn't smart enough back in the early 90s....

[booested4door]

Tested voltage right out of sensor and it’s pegged lean. The Ecu is probably trying to fatten it up as much as it can. Hence the rich requested afr. … I’m thinking. So may not be stuck in open loop… just other issues.
Has no boost leaks or anything like that. The shielded o2 wire to Ecu has continuity but also higher resistance. Need to test more. When i installed this harness a few years ago, the plastic o2 plug was broken and needed to be cut off. If i remember correctly, i stripped both wires and connected them to a terminal. Testing my parts harness resistance on that o2 signal wire netted .5 ohm resistance. I’m thinking i botched the repair! How would this get done correctly? What do i do with the ground wire in there? Not sure if anyone’s messed with that or not.