Author Topic: Loss of compression in all cylinders? (Read 5023 times)

Quincy56 · « **on:** June 01, 2009, 09:07:24 PM »

My daughter has a 91 318 that won't start. They have just checked the compression and there is nothing on all cylinders. The headers are loose, so a clogged exhaust is out. Is a failed/broken chain common? It seemed good when I checked it last year, but now the car is on the opposite coast...

Anything else that could cause this?

tjts1 · « **Reply #1 on:** June 01, 2009, 09:17:46 PM »

Hard to tell without removing the valve cover but timing failure is likely. Either chain, tensioner or guide rail.

DesktopDave · « **Reply #2 on:** June 01, 2009, 09:21:32 PM »

Is it a mechanic doing the checking? I'd wonder if they did it with the throttle body open...I'm also wondering what your readings would be with a few spoons of oil in the bores. Hopefully it's a bad reading and the car isn't running for some less expensive reason.

When you checked the chain what did the cam gear look like?

Timing chains can skip in these cars (bad tensioner, chain guides shot), bending intake valves and making for no compression (a leakdown test would confirm that). Shedding links and worn/cracked chain rails seem somewhat common on high mileage cars. There's also the loose bolts in the upper oil pan working loose...causes oil starvation.

Quincy56 · « **Reply #3 on:** June 04, 2009, 08:34:50 AM »

Ok, here is the current situation.

All cylinders read zero compression.

The timing chain looks OK. Tight, and the timing marks seem to be lining up correctly.

The valve train is moving properly.

We added some oil to each cylinder and there was no change in the compression.

Any ideas? Seems very strange to me..

John

B318M42W · « **Reply #4 on:** June 04, 2009, 10:35:38 AM »

a) valves ?
b) his instrument is blocked ?
c) change mech ?
d) clogged air intake / air filter

keflaman · « **Reply #5 on:** June 04, 2009, 05:01:15 PM »

I hesitate to say what they are telling you is impossible, but...there most likely has to be a problem in the valve train.

Four broken connecting rods?
Cam lobes worn away?
Holes in all four pistons?
Aliens?

Time to haul out the leakdown tester.

DesktopDave · « **Reply #6 on:** June 04, 2009, 05:13:32 PM »

That's a surprising one to me too. Maybe the valves are stuck open with carbon deposits? Massive head gasket failure?

Any evidence of pressure bubbles or oil in the coolant?

A cracked/warped head would do that. If the head is warped and the gasket ruptured between the cylinders it might show no compression/no milkshake oil/no pressurized coolant.

B318M42W · « **Reply #7 on:** June 04, 2009, 08:48:18 PM »

might want to follow this thread too... seems like he's getting zero compression also.
http://forums.bimmerforums.com/forum/showthread.php?t=1245494

twright · « **Reply #8 on:** June 05, 2009, 07:06:23 AM »

My prediction is that the timing has jumped a tooth or two and the valves have contacted the pistons. All (or most) of the valves are now bent and stuck open.

Quincy56 · « **Reply #9 on:** June 05, 2009, 10:01:34 AM »

Wow, that is way to strange, that other post has all the same symptoms, including a recently replaced cat. Loss of power just before it died, then nothing but an occasional "poof".

CCE30 · « **Reply #10 on:** September 06, 2009, 12:27:00 PM »

Do you have an update to this? I'm also working on a 91 318i with a no-start issue.

Has spark, sensors/relays and fuel pump is in order. Determined it's not a fuel issue. There is zero compression in the cylinders.

I'm going to open up the valve cover to take a peek. We're suspecting bent valves also.

dj91318is · « **Reply #11 on:** September 06, 2009, 01:23:30 PM »

I would check Valve adjustment as if your adjusting them. This should tell you if the Cams / Chain has jumped teeth pistons at top dead center.

B318M42W · « **Reply #12 on:** September 06, 2009, 02:36:54 PM »

just out of curiosity... is the engine able to breath at all??? if no air makes it to the cyl, normal you can't get any compressions...