e30 hesitation at freeway speeds

[turge]

UPDATE:

Now I'm getting error code 1251, meaning one of my injectors could be bad, even though I just had em replaced and refurbished. I believe my DME is functional too considering I've tried using several from friends cars and I'm still getting the same error.

On that note... the car's still hesitating. I have a new coil, rotor, distributor cap, CPS, CTS (sender and the other one up there), a new O2 sensor, a new fuel pump and a new grounding cable. There could be a vacuum leak or my CAT could be clogged but I'm not 100% sure.

The good news is my idle problems went away with the new grounding cable and the new stuff I listed above.

Check the video to see what my car is doing when the light comes on and RPM guage flips out. Note it is doing it at freeway speeds. All I really have to do to get it to spazz out is to go from say 1/4th a throttle to full throttle above 60mph and it will backfire like shown and heard in the video. Also... this problem is not letting me go past 80mph... which means I won't keep up in the Caravan to Bimmerfest this year. :(

This has been happening for a few months now and the codes usually happen when I go around 80mph and when I'm at full throttle or 4/5th throttle. I've tried everything I could think of including changing AFMs, switching back to my stock 153 ECU (which just threw a constant CEL when driving so I switched back to my 173 with Dinan chip), replacing all 3 relays (the ones by the coolant reservoir), the O2 sensor, the intake boot, cleaned the AFM and throttle body, replaced ICV and cleaned it, and I fixed my exhaust and tightened every thing back up to prevent exhaust leaks throwing the code.

I'm going to replace the spark plugs and the fuel pump tomorrow to see if that fixes anything. But any thoughts on what could be causing it?

Note I currently have 17lbs m50 injectors installed instead of the stock m20 ones.

[jeffnhiscars]

I sure cant rule out any or all of your mods, but I got rid of a 1222 today with a new intake boot. Boring but true.

[FLG]

Have a shop with a smoke machine check for intake leaks.

[bmwman91]

1222 is most commonly due to vacuum leaks, although usually more at engine idle. Does the car idle smoothly?

[turge]

1222 is most commonly due to vacuum leaks, although usually more at engine idle. Does the car idle smoothly?

It idles fairly smooth most of the time, but it sometimes idles weird on startup.

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[dnguyen1963]

check the elbows going into the throttle body. They are a commonly missed source of vacuum leaks. And, please get a smoke test done.

[turge]

check the elbows going into the throttle body. They are a commonly missed source of vacuum leaks. And, please get a smoke test done.

Well 1222 went away after fixing those 2 vacuum lines that are on the back of the throttle body. Still getting 1261 though. :/

[jlevie]

A 1261 will be a bad fuel pump relay, bad fuel pump relay socket, bad DME, or bad engine harness. You can try a new relay and contact cleaner of the socket. But if the code persists with a known good DME, the harness will have to be replaced.

[turge]

bump. Now I'm getting error code 1251, meaning one of my injectors could be bad, even though I just had em replaced and refurbished. I believe my DME is functional too considering I've tried using several from friends cars and I'm still getting the same error.

On that note... the car's still hesitating. I have a new coil, rotor, distributor cap, CPS, CTS (sender and the other one up there), a new O2 sensor, a new fuel pump and a new grounding cable. There could be a vacuum leak or my CAT could be clogged but I'm not 100% sure.

The good news is my idle problems went away with the new grounding cable and the new stuff I listed above.

Check the video to see what my car is doing when the light comes on and RPM guage flips out. Note it is doing it at freeway speeds. All I really have to do to get it to spazz out is to go from say 1/4th a throttle to full throttle above 60mph and it will backfire like shown and heard in the video. Also... this problem is not letting me go past 80mph... which means I won't keep up in the Caravan to Bimmerfest this year. :(

[jlevie]

The behavior of the tachometer says that the DME is loosing power or loosing timing data. With a new CPS installed, that means the engine harness, DME, main relay, etc.., are suspects

[turge]

The behavior of the tachometer says that the DME is loosing power or loosing timing data. With a new CPS installed, that means the engine harness, DME, main relay, etc.., are suspects

So should I try and find a new wiring harness or what do u think is most likely the culprit?

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[FLG]

Had a similar issue, turned out to be the plug on the firewall next to the fuse box (one thats clipped on the firewall to the side of the fuse box) try unplugging and cleaning it.

Also did you ensure CPS air gap? Finally what brand CPS? I had issues with NON OEM CPS's to the point where the car wouldnt even idle correctly.

[turge]

Had a similar issue, turned out to be the plug on the firewall next to the fuse box (one thats clipped on the firewall to the side of the fuse box) try unplugging and cleaning it.

Also did you ensure CPS air gap? Finally what brand CPS? I had issues with NON OEM CPS's to the point where the car wouldnt even idle correctly.

Well as I said, I replaced the ground cable, the coil, and the distributor cap and rotor. I also cleaned the ICV, throttle body, and AFM. But, in the morning I will go buy some electrical cleaner and clean all of the connectors. I just did some more research as well and apparently cleaning the the ECU and diff sensor connectors with electrical sensor cleaner can fix the problem.

The air gap on the CPS seems to be correct, and I believe it was an OEM one that I bought off BMA. And I would think the CPS would be fine since my car idles fine now. If the CPS was bad, I would assume that I would be having more problems with the car then I am currently having.

[mrDSP]

I'm having almost the same issue with my car, except its hesitating in every gear - did the contact cleaner help/did you find the problem?

[turge]

I'm having almost the same issue with my car, except its hesitating in every gear - did the contact cleaner help/did you find the problem?

It helped a little. I think it might have been a clogged CAT too. That being said, I don't have my car anymore since I r3vd it, so I never found out what the underlying issue was :|

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