M30B35 not sounding very good

[grr]

http://sublime.stud.hive.no/535-rot/535_2.wmv (1MB)

This just doesn't sound right. Anyone recognise the sound and wanna tell me what's wrong with it?

The exhaust on it _is_ loud (cat removed, etc..), but there's something else not sounding right..

[mholbrook]

Really hard to get much out of that clip. Get a long handled screwdriver and put the point on the engine and ear to the handle. Probe around until you find the source of the sound if possible. Looked like the idle was around 700-800 which is about right I think. Other than that I have nothing.

[grr]

Yeah, I think the idle is fine, but doesn't it sound like it's running really rough?

[motorman]

Doesn't sound too good, does it. Need to start with the basics, check plugs, leads, dizzy cap, rotor button (when last did you change them). Also check for vacuum leaks as this can cause rough running, if not, problem could be either spark related or fuel (when did you last change your fuel filter), check your fuel delivery rate and fuel pressure, next afm. Did the problem happen suddenly or gradually? this can be a clue as to what could be wrong.This will give toy a place to start and these are the most common causes.
Hope this is of some help. Cheers Mick

[grr]

The car is originally a 520i M20, but the previous owner swapped the engine with a M30 from a '87 E28 M535i, with E34 535i ECU and E34 535i wiring harness. He never got it running, which means it hasn't been driven the last year. I bought it a few days ago, so I don't know the engine or the cars history, but as you can see it's running now, only a bit rough. I checked the distributor cap a few days ago, and it did look pretty worn..

Does it sound like it's missing any cylinders, or what? I'm not familiar with M30 engines, I've only had M20s and M50s before..

[Rory525]

Why is your temp guage right into the red?

Is it broken ?

[grr]

Why is your temp guage right into the red?

Is it broken ?

Yeah, it goes into the red when I turn on the ignition. I'm guessing the previous owner haven't had it properly connected after they swapped the wiring harness. Either that or the sensor is a bit different on the E28 M535i vs. the E34 535i. I'll look into it when I get the engine running properly.

[Rory525]

When did this bad running start? Did you use the car daily then suddenly it started running bad ?

Or has it been sitting unused for a long while and now when you start it you get that ?

If its been sitting for a long while Id run the engine for a while and rev it a bit - it often clears up problems like that where its just some dampness.

[grr]

As mentioned above, the engine probably hasn't been running for about a year. I'm not sure I wanna rev it like it's running now.. even though you may very well be right. The "knocking" sound you hear every now and then in the video clip worries me a bit.

How about the sensor on the pulley - could a few tenths of a millimeter to or from be doing this?

[Rory525]

As mentioned above, the engine probably hasn't been running for about a year. I'm not sure I wanna rev it like it's running now.. even though you may very well be right. The "knocking" sound you hear every now and then in the video clip worries me a bit.

How about the sensor on the pulley - could a few tenths of a millimeter to or from be doing this?

Really not sure about the sensor thing.

I didnt notice you said it hasnt run for a year... Im pretty sure it will just be dampness. Have you tried swapping plugs ? Clean up dizzy etc might just be moisture in there. Pretty sure it will be nothing major as its just been sitting. Tough old things the M30