Sporadic rough running/cel

[parkerbink]

My new to me '92 would not idle/drive or stay running when I got it. new plugs, cleaned EGR/IAC & replacement MAF and it runs ok for about 15 minutes then I get the cel and rough running and a few minutes later it dies. After 10 minutes sitting it begins this cycle over.

I ran the codes with a Peake scanner and it's all egr/emissions related but all of the hoses are new & properly connected.

I need to get it smogged to register it and paid for a three day temp registration and would like to get it done by Friday when it ends. (that 1.00 is a whole lotta $$$)

lol


Thanks in advance.

[MrBurgundy]

Also, check the the fuel pressure and the fuel pressure reg.

[parkerbink]

It has a new pump, I don't have the tools to check pressure but ordered new injectors so if that does not resolve it I'll need to take it to a shop.

Thanks

[MrBurgundy]

If you have good fuel pressure and the regulator isn't sending gas to the intake, then I'd start checking your spark.

[EyExR]

Check for spark at every plug?
Loose/worn C191 connector?
Vac leak?
TPS working right?
O2 sensor?

You really have to go through the "list"... easiest/cheapest tests first.

[parkerbink]

Spark fuel and compression are all good, it seems like some state is changing after a period of time in the ECU because it is fine for 15 or so minutes and clears after about 10.

I am waiting for the OBD1 to 2 adaptor I bought to come so hopefully I can se what the ECU is doing.

Thanks

[parkerbink]

Checked C191 it's clean and intact, hit all the connectors with contact cleaner. Also I have two disconnected connectors, one I found was an alarm not available in the US anyone know what this one is (comes out of the main harness going to the fuse box)

[parkerbink]

Stomp test says 1222 Lambda Control 1.

Ordering 02sensor now.

[parkerbink]

Looking to clear the code I found you have to stomp again to move to the next one and had 1221 (02 sensor also) that was all the codes, the write up I found said after the last code stomp 5x holding the accelerator down after #5 for 15 seconds.

No joy. Am I missing something or doing the wrong thing?

[parkerbink]

Replaced the 02 Sensor, I was able to get to and pass smog but it still started running rough after 10-15 minutes but a 3 minute shut down & "reboot" restored function.

It had a 261 200 525 Motronic but came with a 261 200 173 which I put in and it is running for over 30 minutes with no issues.

[cirrusblue]

Replaced the 02 Sensor, I was able to get to and pass smog but it still started running rough after 10-15 minutes but a 3 minute shut down & "reboot" restored function.

It had a 261 200 525 Motronic but came with a 261 200 173 which I put in and it is running for over 30 minutes with no issues.

Replace fuel pump relay. No bs. You get all kinds of issues like this. Its cheap and easy and when it goes its inconsistent how it behaves. Many guys keep a spare in the trunk


Sent from my iPhone using Tapatalk

[parkerbink]

Thanks, it started doing it again but since I had the computer accessible turning the car off & pulling the plug for a minute fixed it. It's weird, the code is still 1221 & 1222 although it has a new sensor.

I'll have the relay in the morning.

[cirrusblue]

Thanks, it started doing it again but since I had the computer accessible turning the car off & pulling the plug for a minute fixed it. It's weird, the code is still 1221 & 1222 although it has a new sensor.

I'll have the relay in the morning.

Good luck


Sent from my iPhone using Tapatalk

[parkerbink]

Did the relay, no change. Since the TPS is the only remaining part I just swapped it. I took a picture of the position of the module and screws and followed the write ups I found regarding making sure the throttle plate was closed and it idles like the MAF is disconnected. I took everything apart again, verified the throttle is closed and tried to make it exactly like it was no real change.

How the f00k do you adjust it when everything is together?

[EyExR]

I'd really suspect the AFM (even though it's a replacement) and CTS.