3.3 EFI Turbo: Compression Test Results

[WydRyd]

Thought I'd post these numbers in a new post, since I'm all over the place these days trying to diagnose my low idle/stalling/power-loss issue

OK, these are the numbers I get doing a cold compression test:

# 1 = ~100
# 2 = ~110-115
# 3 = ~110
# 4 = ~110-115
# 5 = ~110-115
# 6 = ~110-115

I know compression tests should be done warm and is only a rough guide to the condition of the engine internals. If I had a compressor and leakdown tester, that would be the next test I'd be doing on Cyl # 1.

Anyway, my main concern with these results is Cyl # 1

Whilst it isn't significantly lower than the others (~10% variance), it raises some cause for concern and further troubleshooting.

I know the typical causes for lower compression could be attributed to:

- Worn rings
- Cracked ring land (BTDT!)
- Pulled head stud(s)
- Valves
- Head gasket

Question:

If I had only one blown out head gasket, could it be causing low idle/stalling?

[slow&rusty]

I would not be worried about No.1....hard to determine cylinder health on a cold motor...was the throttle open?

100psi is inline with your other numbers....do not worry.

Which EFI are you using?

Yasin

[WydRyd]

Throttle wide open.

Using the OEM Motronics EFI.

So I guess thehunt is still on

Must be either fuel system or ignition

[porschett]

My #1 had low compression numbers compared to the rest also. Turned out to be a broken #2 compression ring. Played around with the boost controller too much and hit overboost a couple of times.

This may not be your problem, but just FYI.