LOUD Tapping, stalling at idle, exhaust smells of gasoline. Opinions?

[CShep]

Solved: the car needed a new distributor rotor, and air flow meter to get it running right. A valve adjustment and some heavy weight conventional oil took care of any residual ticking left after the repaired rotor.

I'm wondering if anyone has any thoughts on what could be causing these symptoms. Here's what happened, and what's happening.

I am the proud owner of an '87 325is, although I have only got to drive it a few times. I purchased the car with 130k on the clock, and it was running very well. None of the typical bouncy idle, loud valve ticking, etc. I drove it home (about 60 miles), and let it sit for a couple of weeks while I got it registered.

When I started the car after those couple of weeks there was a bit of what sounded like valve tapping, but the car ran and drove fine, and it wasn't too loud. I drove the car about 5 miles, round trip that day, and parked it.

The next day my wife went to use the car, and it wouldn't start for her. She took another car, and later that day I went to see if I could figure out what the problem was. I got the car started, and all of a sudden it was hugely loud, and ran poorly. The symptoms were:

- What sounds like extremely loud valve tapping (I've owned 2 other M20 cars over the years, and never heard the noise approach these levels). The tapping was RPM dependent, and got louder as RPM increased. It almost sounded like there was a loose bolt rattling around in the cylinder head (there wasn't, I checked). My neighbor accross the street, who is a retired mechanic, thought that the problem was a loose valve after hearing the noise.

- Rough idle - it wanted to die after it started, but would stay running if I gave it a little gas. After about a minute of that it started idling on its own.

- The exhaust has a strong smell of fuel. It wasn't smoking, but it smelled more than exhaust usually does.

So after experiencing these symptoms, I shut the car off quickly. I've since done a bit of poking around. Here's what I've found:

- The timing belt does not appear damaged, either frayed, cracked or broken, but I haven't checked the tensioner yet.

- The engine still turns over freely, and would likely start, although I'd rather avoid having to start it again until it's been diagnosed (don't want to cause further damage if it can be avoided).

- The valve clearances do not appear to be loose. I couldn't fit a .23 gauge into the any of the ones that were at TDC when I parked the car, none are easily moveable by hand, and none of the adjuster nuts are loose.

I was thinking of going through and adjusting the valves anyway, since it seems like they could be a culprit, and it never hurts to get that job done, but once I saw that none were exceptionally loose, I started to think that maybe the problem didn't lie there.

The car went from running quite well, to barely running, and sounding like it was breaking itself to bits.

Any thoughts on what could cause the sudden onset of all of these problems?

[jayuuey]

i would definitely try the valve adjustment, check for loose or broken ignition rotor, tb tensioner. just hope the timing belt didn't jump a few teeth if the tensioner came loose.

[3vilE30]

Post up a vid and make sure to get a shot of the cluster in as well.
I would check the oil to make sure, I picked up a 325iS that had synthetic in it. The rockers sounded nasty switched to diesel oil and it turned back to typical m20 tick.

Also see if disconnecting the battery helps and try disconnecting the 02 to see if it idles better.

[dnguyen1963]

Rotate the engine by hand and check the timing.

[CShep]

So i got a chance today to break the car down a bit today. First day in the 80s since last year, so I was just happy to be outside. Here's what I found:

- Engine turns over without excess resistance throughout 3 full revolutions of the timing belt. Did not feel or hear any collision of pistons and valves.

- Timing marks are dead on, both bottom and top.

-Timing belt appears to still have plenty of tension. It doesn't feel any looser than a freshly done job. The tensioner itself looked fine as well.

- Dist. rotor is not in great shape (the little metal bit at the end is fairly rough), but not loose or cracked. I could see this affecting performance, but I'm not sure that the onset would have been so quick and catastrophic. Thoughts?


I neglected to mention something the first time around, and while I'm not sure if it's relevant, I figured I'd put it here. The battery ran out of juice while the car was sitting and waiting to be registered. I had to jump it that day, and it seemed to hold charge on to the next day, but perhaps it was lower than spec. I'm not sure hpw that would cause such loud ticking, but I could see it possibly affecting idle. Just throwing it out there as a low battery has done some funky things to my e39.

I've also read the failing injectors can sometimes tick, but I havent heard the noise myself. Are they this loud? Could they be a possibility here?

Any other suggestions before I adjust the valves, put it all back together, and try to start it? I've got another e30 here ('90 325i) and I'm not opposed to swapping parts back and forth, if that's what it takes.

I can put up a video, if the problem persists after valve adjustment.