91 318i, ran great, start it back and it runs horrible!

[90pioneer]

Just bought this 91 318I. 178k. I drove it 9 miles and it ran perfectly, shut it off, start it up 15 minutes later and it is running horrible. Lacks power, sounds like a diesel and shakes badly. Engine is missing real bad, but runs "better" over 3500 rpms. Almost like I lost a cylinder???

Where should I start? Most confusing thing is it ran absolutely perfect until I shut it off, started it up, instant awful shaking. The rpms at idle remains a pretty steady 750. Have to rev the hell out of it to get it moving.

I did a quick look in the engine bay, nothing appears wrong right off hand...didn't see any hoses disconnected....

[Ryann]

Sounds to me like your timing set could be wasted. Pull your valve cover and post some pics for us.

[90pioneer]

Sounds to me like your timing set could be wasted. Pull your valve cover and post some pics for us.

I can pull it tonight... I need to drive 14 miles home... is that going to ruin my engine?

[Ryann]

If you've jumped time already and you continue to run it that way then yes, it will likely jump again and make things worse.

[90pioneer]

If you've jumped time already and you continue to run it that way then yes, it will likely jump again and make things worse.

Why would it just jump timing? What should I look for when I pull the valve cover? Never pulled one before.....

[Ryann]

e30 m42's came with a weak chain tensioner piston. It allows your timing chain to go slack and beat the piss out of all the guides and gears. Eventually things get sloppy enough that your cams can get out of time.

It's been covered extensively here in the r3v m42 sub-forum, and also on m42club.com.

Also, noticed your spark plug/oil thread. Has this been addressed?

[peytonracer4]

yeah i'm really thinking something timing wise went on you. it's too hard to tell what without pulling the valve cover.
pull the valve cover and you'll see a chain on two sprockets on the front side of the engine. look at the teeth for extreme wear. you're going to really need to check the exact timing though. there's marks on the sprockets. little arrows. i think they're supposed to line up but you might want to search because i'm not 100% on that.

[90pioneer]

e30 m42's came with a weak chain tensioner piston. It allows your timing chain to go slack and beat the piss out of all the guides and gears. Eventually things get sloppy enough that your cams can get out of time.

It's been covered extensively here in the r3v m42 sub-forum, and also on m42club.com.

Also, noticed your spark plug/oil thread. Has this been addressed?

I haven't fixed the spark plug oil yet. Today was the first day I've driven the car... just redid the front suspension.

I don't think the timing chain tensioner in it is all that old though... will pull the valve cover and post pics tomorrow...

If the timing does turn out to be off, how do I adjust it? I do have a new chain tensioner sitting on my table.

[90pioneer]

Also could a bad injector cause these problems?

[Ryann]

you're going to really need to check the exact timing though. there's marks on the sprockets. little arrows. i think they're supposed to line up but you might want to search because i'm not 100% on that.

A quick look at the square ends of the cams on crank TDC #1 would tell all.

OP: one or more oil fouled plug wires could cause a misfire, but judging by your 'diesel' description it's likely the timing set. There could be other things going on here but the easiest things to check at this point are under the cover.

[90pioneer]

A quick look at the square ends of the cams on crank TDC #1 would tell all.

OP: one or more oil fouled plug wires could cause a misfire, but judging by your 'diesel' description it's likely the timing set. There could be other things going on here but the easiest things to check at this point are under the cover.

FOUND THE PROBLEM!!!

The spark plug gasket on the number four cylinder has failed, allowing oil to blow up into the spark plug wire connector fouling it up. I cleaned it up and it ran much much better, but still not perfect. Drove it around the plug, pulled the plug connector again, and noticed a fresh coating of oil in it.

I think I will replace all the plugs and wires, and put a new plug connector on the 4th cylinder.

I will also do a new valve cover and spark plug gaskets at the same time.

Pelican parts, here I come...

ETA Pelican doesnt seem to carry spark plug wires... and the other sources list them at near $200 bucks. Think I'll try not replacing them!

[Gerta]

blunttech ... it will save you some cash. Steve@blunttech.com.