Sorry for the tl;dr.
Car is a 1987 (Man. 09-86) 325es.
Got the garage-kept car last September from the original owner with 127k miles. Ran great when I bought it and was running great up to early April. I had been changing the oil and filter every 3k miles (daily driver in the city), changed the air filter, spark plugs, fuel filter, tranny and diff fluids.
The first project I wanted to do was change the timing belt. Not that the belt on the car had a lot of miles on it, but that it was getting a little old- last changed in December of 2005 at 124k miles. I needed to do it to get rid of my worry about the belt and to replace everything else that goes with that.
The first weekend of April I decided to tackle the project. It took most of the day, but I got it. I made damn sure the marks were lined up before I put the belt on and again before I put it all back together.
I went to crank the engine...it just cranked over and over. First thought was bent valves, but, I didn't have the time to fiddle with it all weekend. Had it moved to a friend's place and it sat there until earlier this month.
1. A couple weeks ago I went to go check the car out. Cranked it again for the hell of it- still wouldn't start.
- Checked the spark plugs: no spark
- Checked the coil: plenty of spark
During this the cranking was smooth, it just wasn't firing.
2. Unscrewed the cap and I see I screwed the new rotor on just a little tight; the rotor was in two pieces, and, the cap had a few bent prongs and was cracked.
3. I did keep the old cap/rotor since there was nothing particularly wrong with them. I put those back on and crank the engine, but, it was a rough crank. I'd describe it as starting to crank OK, but then almost completely stopping, and it would sound as though the starter was trying it's damned hardest to get the engine to turn-over.
I gave the engine a little throttle and it did start with the same rough crank, and, after I let me foot off the pedal, the engine immediately died.
4. Did the same as above but kept the throttle half open after starting. The engine ran rough, though, it didn't quite sound like bent valves (no metallic clanks), more as though it wasn't firing the way it should.
5. Checked all the plug cables to be sure they were plugged into the cap right.
6. Did a compression test and got these results: 145-145-160-155-155 (psi). While the plugs were out for the test, the engine cranked fine.
- Cylinder 4's (frontmost) plug, however, was fouled completely black but dry.
7. Cleaned #4's plug off as best I could and put all the plugs back in. Cranked the engine, which cranked without the previously experienced hesitation, and started without help on my part.
It still ran rough, but gets less rough after a half-minute of idling. Roughness goes down a little more if revved to about 2k.
8. Checked #4's plug and it was completely fouled again.
Thanks for any help.