E30 m20b27 running super rough...

[masonday32]

Hey guys, i have 86' e30 325es with the 2.7l in it. I got it back from the transmission shop a few months back and got it all put back together and it ran great. I put a super sprint exhaust (headers are oem) on it and ran it for about a week without the o2 sensor in it. At which point it began to run incredibly rough to the point where 5-8 mph is my top speed... i have a new oem o2 sensor in that exhaust but the sensor is set about 2-3 feet closer to the headers than the original exhaust was. Im not sure if that could be an issue. I've replaced pretty much every gasket and seal there is (probably looking at doing the head gasket today bc its the last one i haven't done), all of the spark components besides the wires (tested other wires and it was the same), the fuel is bad im sure but i don't think it would cause it to run THIS badly. I'm going to replace it with fresh fuel today as well hopefully. Ive replaced the exterior fuel pump but not the in tank fuel pump. Could the car still get gas from the tank if the in tank fuel pump was dead? Or could it be a blown head gasket? Or possibly something to do with the valves? I've never had those issues until i swapped the exhausts and the o2 sensor broke out of the other exhaust due to rust... HELP!!! lol

[superj]

Have you checked to see if all the different things are within their specs?
Fuel pressure
Tps readings
Wires are right
Afm reads right
And you are sure the trans is not messing it up?

[masonday32]

I swapped out the fuel pressure regulator last night with a different one and it ran the same. I also swapped out the injectors from another e30 that had no fuel issues. This all gradually happened after it ran perfect for about a week. it was a gradual tough start then it became more. I'm going to check the wires this week. Any tips on testing the AFM and TPS? The car drives just fine transmission wise. Shifts smooth, no noises, clutch pedal feels fine. I had every piece in it replaced before this happened.

[masonday32]

I've been looking around a bit and I've seen some videos. Could it be a broken rocker arm/valve? or would i hear knocking?

[superj]

is your cold start valve running the whole time? that will make it run poorly because it will be very rich. maybe unplug that and see how it does?

is your exhaust plugged? I just have random ideas because its hard to check not being there. the Bentley manual has all your info for specs and how to check them. check pelican parts and I think they have a technical section with info

[Jeffnhiscars]

If the in tank pump was dead you'd hear the external pump sucking it's brains out (aka cavitation). Bad fuel is bad kharma and after running without an O2 sensor I'd disconnect the battery and let the ecu relearn.

The tps should have continuity at idle and WOT with none in between.

[323i E30]

I've been looking around a bit and I've seen some videos. Could it be a broken rocker arm/valve? or would i hear knocking?

You would hear a sort of flapping sound, likely accompanied by a metal dinging every now and then.
Even with the serious power loss, you'd still be able to drive on the highway with it.
Doesn't really sound like your issue.

[ELVA164]

Lots of things to look at.

How do the plugs look?
How is spark at each plug?
What's fuel pressure at the rail?
Are all the plugs/sensors on the intake plugged in and working?
What's the valve lash at?
Is your cold start valve functioning properly?
Try swapping the DME and see if the problem persists. Etas also have an idle box or something you could look at, but I don't think that's related to your issue.

[Delanoso]

When was the last time you checked the fuel tank? I had rust clogging the pick up on the in tank pump on my '86 eta, which caused a similar issue. If I was *really* easy on the gas I could get the tach up to almost 3K but if I asked for more it nearly stalled. Had to replace the tank and both pumps.

[superj]

also, since you swapped injectors, were they from another 325e? I injectors will cause you problems because they have a different impedance reading. I believe they will burn out your ecu injector driver, on the mother board