cluosborne

Hi, I did do some searching in the archives and read about similar problems, but none seemed quite right. Maybe, you could help.

This morning, and up until around 11 A.M. EST, my non-Turbo 88 Gtu was running and idling great. Engine sounded fine, had no hesitation, and didn't stall. Just as I was turning onto the last road to a school where I was going to do some tech work, I down shift and suddenly I lose power and the engine stalls out. I coast to the side of the road and restart the engine. The engine cranks, but it sounds like it's badly flooded, even when I disconnect the fuel pump relay. I manage to get it started but it will not hold idle, hesitates and revs slowly. I manage to limp back home at the end of the day.

Here's what I know right now:

1. Engine will crank and still sounds like it's flooded (I guess you could describe it like it's easier for the starter to crank the engine, higher in pitch I suppose).

2. The engine will run, will rev past 4000 RPM and sounds ok, with the exception of the hesitation, slow reving and lack of power. Oil pressure at 3000 RPM is 60 PSI as it should.

3. There are no fuel leaks, and no strong fuel smells coming from the engine compartment.

4. It doesn't smoke, no indication that this is a coolant seal failure.

5. At this point, I can only start the engine by cranking with the fuel relay disconnected and then reconnect it when it barely revs to life.

6. Air intake and ignition seems ok. The air filter is dirty, but doesn't appear clogged.

What I don't know at this time is:

1. Engine compression

2. The condition of the spark plugs (they were replaced by non-NGKs--at least I think they aren't NGKs--several months ago, but the engine ran fine with no problems)

3. Fuel pressure

I've narrowed the possibilities down to four causes: (in order from most to least expensive to fix)
1. Blown apex or side seals
2. Bad/worn out fuel pump
3. Clogged fuel filter
4. Bad spark plugs

From what I've read in previous posts is that if an apex seal blew, the engine wouldn't crank at all. However, given how the engine sounds when it cranks--not runs-- makes me think it could have lost compression.

I've also considered the possibility of a vacuum leak and noticed an open vacuum nipple, but plugging it didn't make any difference (I'm planning to replace the hoses with silver silicon this winter). I didn't see anything else visually wrong. Also--and this was on the planned things to replace list anyway--I ordered a new fuel filter as well.

I'm going to buy a fuel pressure gauge and a compression gauge (I've already got a how-to on properly checking compression and the modifying of a conventional compression gauge) and check these readings, but I wanted your opinions since this problem isn't quite like any other that I've read about (and I'm assuming the worst right now, which isn't helping my nerves any, so having a second opinion could help clarify my thinking).

Finally, however it turns out, thanks for taking the time to read this post.

J-Rat

iTrader: (2)

Some engines will run on a bad apex seal. I had an N/A that ran and idled with 2 bad seals.

A compression check will yield you some answers.

Jarrett

cluosborne

I did some more research and it's more than likely it's a blown apex seal. It would account for the way it sounds when it cranks, and the bad idle.

So, today, purchase a pressure gauge and a fuel pressure gauge and confirm my worst nightmare :-).

But, until that nightmarish moment arrives, I'm not going to conclude it's a bad seal.

DraygenX

yup I tend to agree, I had my 90 gtu do the exact same thing and it ended up being a blown trailing apex seal, all of a sudden, I lost power, the engine stalled, tried to restart and could keep it running if I gave it alittle gas and it had a rough idle and no power

DraygenX

yup I tend to agree, I had my 90 gtu do the exact same thing and it ended up being a blown trailing apex seal, all of a sudden, I lost power, the engine stalled, tried to restart and could keep it running if I gave it alittle gas and it had a rough idle and no power, good luck with it

Snrub

iTrader: (1)

Not to say that it's blown, but my car was able to run pretty well on 1 rotor and one completely nuked. It idled steady and could rev to the redline.

cluosborne

Take my word for it, it won't rev to the redline, it won't idle steadly, and it doesn't even sound right when I crank it.

I've got a compression tester, and tomorrow, the moment of truth. I'm already planning on pulling the motor and finding another.

cluosborne

And the result is in. My front rotor has a blown seal. When I attached the compression tester, I got a low-low-low reading (as in barely over 25psi) from the front rotor, and high-high-high (just over 50psi) from the rear rotor. I'm definitely hearing only three compression pulses now.

So, anybody got a good used 1986-1988 short block for sale? I live in Northeastern Michigan.