URGENT! CAR COMPRESSION ISSUES

[RyannAspire]

Need help soon as please guys!

My car has been off the road for about 3 months as I've been away. Started the car one afternoon and it sounded like it was running on 3 cylinders, after a couple of minutes it cleared and was running fine. Stopped off at shop,came out, started up again, sounded the same then cleared again. Drive home, just as I turned into my road it sounded really lumpy, then cut out.

Won't start on the key. I tested compression and cylinders 1-3 were at around 35psi and cylinder 4 at 60psi. Dropped a bit of oil in by the spark plugs and brought compressions up a bit to around 40psi. We then towed it down the road and bump started it that way, it started but sounded rough/ like 3 cylinders again, but would stay running as long as we kept revving the engine.

Tested compression again and all cylinders were at around 70psi. Then found cylinder 3 is misfiring also, my suspicions for the misfire is the injector. I have a spark on all cylinders and can smell fuel to .

Not sure what can cause the low compression though. Could the cambelt have jumped teeth or something?

Thanks in advance

 

[montana]

Could be a damp issue in the ignition parts due to being stood for 3 months ? How we're the plugs when you removed them ? Worth checking the leads too. Failing that take it for a longer run up to temp and see if you still have the issue

 

[RS Charlie]

I would be tempted to try another gauge unless your engine is flooded. 35PSi is far too low.

 

[smith647]

Did you remove the throttle body when doing the compression test?

I'm guessing from your readings you didn't. Redo test with it either held to WOT but if you've got a 182 with in being electronic, remove it.

 

[bloke]

Did you remove the throttle body when doing the compression test?

I'm guessing from your readings you didn't. Redo test with it either held to WOT but if you've got a 182 with in being electronic, remove it.

erm...

 

[smith647]

@bloke erm... Erm what?

 

[bloke]

upper inlet will be off anyway for compression test:wink:

 

[smith647]

@bloke Haha... So it will :up: I'm new to these cars.

Pretty poor results though.. Something's wrong either way.

 

[Laine_16v]

Consistent drop across all cylinder would indicate slipped timing in my opinion.

 

[RS Charlie]

IME no throttle or WOT makes very little difference to the readings. But as said it is irrelevant in this case.

I reckon the gauge is kaput ; they are variable at the best of times. I know my gauge overreads big time. Most healthy engines make 250PSi of compression according to it or 180PSi or a turbo engine :lol:. That was a new Gunsons gauge as well!

If you wish to get a conclusive result I would try to find someone with a leakdown tester.

If the results are correct slipped timing could be one cause but I would also expect bent valves...

 

[RyannAspire]

Sorry guys, phones been killed last week so haven't been on. Thanks for the replies though!! The compression tester used was 2 weeks old, although from what I've read it could still be crap.

I have taken the injectors out and they are all fine so not sure about the misfire now. Hmmm.

My suspicions are with the timing having slipped. Although when we bump it, it does start and run albeit on three cylinders, surely if there was serious engine damage it wouldn't? I'm not sure I'm just throwing possibilities out there.

What can cause lack of compression?

Someone suggested the piston rings have gone but for all 4 cylinders to go at once would be surprising wouldn't it?

Thanks again fellas

 

[MicKPM]

I agree that I don't trust the gauge. Are you sure it is being screwed in tight as 35psi across all four pots is low.

Your readings are however responsive to oil so I'd say it's either a ring seal or timing issue... More likely timing.

 

[Laine_16v]

You'd clearly be able to tell if it genuinely had 35psi across all cylinders the engine would turn over very fast.

 

[RyannAspire]

You'd clearly be able to tell if it genuinely had 35psi across all cylinders the engine would turn over very fast.

Before we did a compression test my dad said he reckon it sounded low on compression. I can only assume that's what he meant? Maybe it sounds quicker or something?

As much as I will try a new gauge on it. Even if this gauge is out even by a massive 50psi or something for example, the compression is still gonna be massively low. I haven't got any doubt that the engine is actually low on compression but I'm not too knowledgeable so im not sure what could be causing it?

 

[Chrisgti6]

surely it wouldn't fire up at all with compression that low?