Engine locked

[areznik]

Hey guys,

My Q45 '94 (190K miles on it) has been sitting in my front yard for about two months without action. Today I tried to start it up and there was a very strong smell of fuel from the engine (much stronger than a regular smell that I noticed for awhile). The engine barely reved, dying multiple times before reaching even 1K rpms. The battery is new on this car. Then I heard some violent nock and I stopped the engine. Opened the hood, and the fuel smell is very strong. I think one or more of the o-rings was leaking fuel into the cylinder and after two months it just filled the whole cylinder with fuel which prevents it come down all the way (I think this condition is called hydraulic lock and must not be resolved via attempts to start the car or else there is a risk that I might damage the camshaft).

My question, if I remove the upper intake and take the injectors out (obviously replacing the o-rings), can I simply suck out the fuel with a pump and then put everything back ... should this resolve my problem?

Thanks,

Andre.

[audtatious]

you could remove the spark plugs to let the fuel dry out of the piston area if that is truly the issue.

[Q451990]

Nothing in your description sounds good... try drying it out and pray a lot, but I'm guessing your engine is gone.

You might as well compression test it before taking the time to pull the plenum and replace the injector o-rings.

Heath

[areznik]

Heath,

I know the symptoms are not good. Do you have a link to any thread that explains how to test compressIon or if you can tell me step by step?

Would really hate to see the end for my Q.

[Q451990]

Not specific to the Q, but a good rundown...

http://www.youtube.com/watch?v=X_tbksFYhl4

I would disconnect the fuel pump fuse before trying the test

It appears that the tester is available as a loaner tool from Pep Boys, and probably other parts stores. It's the last tool on the left side at the bottom.

http://www.pepboys.com/parts/tools

The factory service manual will give you the dry and wet compression specs. http://www.nicoclub.com/FSM/

Also remember that you probably have a lot of fuel in your oil, so I would drain and refill it with a cheap filter and fresh but inexpensive oil. If you get it all back up and running, then replace that oil and filter with your usual stuff.

Don't be surprised if your dry compression is really low, or approaching zero. The fuel should have washed the oil off of the piston rings, and they don't seal well without some oil film on there. In this case the wet test will be more indicative of what's going on.

Good luck!

Heath

[areznik]

So I went ahead and did the plenum job. Three injectors had flat o-rings. Replaced all o-rings and put everything back. The car started up with lots of smoke coming from the exhaust and eventually after it warmed up the engine seems to work ok.
At idle it has noticable virbration but if I take the RPMs up to 3K the vibration goes away. I went on to adhust the timing and what I noticed is that at normal timing (according to FSM 15 degree) the engine has no power at all but if I retard it a lot it works more like normal.

What might be cause this?

[areznik]

Quick update. Let the car warm up and the vibration became really bad. The idle is stable (the tach is stable). When I put it in drive the vibration becomes much worse to the point where the engine almost stalls (at this point the tach shows a bit of movemnt up and down). I drove around the block and there is no power at all.

Any suggestions?

[Q451990]

Did you ohm test your injectors? The bouncing at idle sounds like failed injectors... It's also possible that you have poor compression on a cylinder or two... something that's slightly bent but not bad enough to keep the car from running at all.

Heath

[areznik]

Heath,

I went on to do the compression test. Removed TB, disconnected all the connectors, removed all spark plugs, etc. and borrowed compression test tool from AutoZone. Started from the driver’s side the first three cylinders showed 120 after a few cranks and then as I continued to test the rest of the cylinders the max compression was half than the previous cylinder which eventually by the time I got to the last cylinder showed no pressure at ll. That was weird. I tried to check the very first cylinder that showed 120 just 15 minutes prior, and now it showed almost no compression. Next day I reattempted again and the same pattern occurred. For the first few tests it showed compression up to spec and then it started dropping as I continued to test other cylinders (this time I started from passenger side). The engine cranks so the cylinders are moving but for some reason the compression drops as I continue doing it for a few times.

Is that pattern indicative of some type of problem or is it normal?

Thanks,

Andre.

[Q451990]

Honestly - I have no idea. I saw a compression test done once years ago, but I haven't completed one myself. I don't think so, but I can't think of a reason it would happen that way.

If the injectors were still squirting fuel, I wonder if it was flooding and washing the fuel off of the rings? Did you try a "wet test" by squirting oil into the cylinders?

Heath

[areznik]

With my luck I ended up with faulty gauge. Went back to AutoZone and got another tester which turned out to work fine. Most cylinders showed 125 +/- 5 compression which I suppose is within standard.

Ok, now that the compression is good how can I check the spark? Is there a test I can do to accomplish this? The plugs seem to be in good shape so I don’t think replacing them would make much difference.

Thanks,

Andre.

[Q451990]

The spec. for compression is 185PSI with 14 psi variance between cylinders. That's specified at 300 RPMs with the throttle body at WOT. My guess is that your compression is fine though...I would have expected to see something really low if you had bent something. Consistency between cylinders is good too.

See page EF&EC 203 for the method for checking spark. It's fairly unusual for the coils or transistors to fail - but I have had plugs that looked "pretty good" turn out to be fouled after an injector failure.

If you haven't ohm tested your fuel injectors yet - I woud certainly do that. They are the most common failure item related that causes a dead miss.

Heath