96 FJ80 died on startup. No compression in all cylinders... (1 Viewer)

[terrx]

I searched and didn't see any similar threads. This is my 1996 with 130K miles and I've owned it since '07. It's never had any problems, not head gaskets, not PHH, non of the often cited issues. Oil has been changed every 3K miles and last change the UOA was fine.

It was garaged for 5 months and I went to start it.... It barely rolls over for a moment, catches and begins to run, but then dies immediately. No pop, bang, etc. Just dies. Starter rolls the engine over but it doesn't start and doesn't sound normal. Spark on #1 cylinder is fine. I pull the plug and there's no compression. Pull #2 and there's none there either. Checked all cylinders and there's no compression in any. This was a static/cranking test, not a leak-down.

Seems like something catastrophic happened and a tear down is imminent. Has anyone run into this before or have any wild guesses?

Thanks.

 

[jpoole]

Perhaps timing chain? Would stationary cams/valve train prevent any compression from registering since no air is flowing?

My 2nd guess would be faulty compression tester or use of that tester but only because I can't think of another cause for lost compression on all cylinders suddenly like that.

 

[vegasfj40]

Something doesn't sound right. If the chain broke there wouldn't be any spark because the distributor wouldn't be moving right? Sounds like the compression test gauge didn't work right.

 

[jpoole]

Extra points for @vegasfj40 for attention to the details I forgot the spark plug firing detail while trying to imagine how compression could be lost on all cyls. at once.

Hopefully it has compression and there's another simple-to-fix issue, possibly in the fuel delivery system, instead...

 

[vegasfj40]

I agree. I was thinking fuel as well.

 

[vegasfj40]

Unless a cam or sprocket broke which would be highly unlikely.

 

[terrx]

I suspected the gauge too and tested it on my FJ40 (SBC). And with spark, the cam must still be rotating, or and I missing something basic about the 1FZ-FE? The only thing I can think of is the cam is out of time with valves open or partially open when they should be closed. Is it possible the cam chain can skip a tooth or two?

 

[jpoole]

It seems like you'd still register compression even with the cams off-time. Spark may be far enough off to prevent running but I'd suspect popping/misfiring in that scenario and some compression.

I still suspect that the compression test could be misleading you here since access to the plug holes is pretty different on your 40. Maybe a slim chance, but possible that it wasn't sealed? Can you put a wooden dowel down over a plug hole, firmly, to see if air pushes it up or hisses past when the engine turns? That or similar may be another way to test for basic compression.

To expand on @vegasfj40 s theory above, perhaps the primary cam broke between the cam gear and the first bearing so that the chain is still turning the stub and the distributor? Seems super unlikely but possible? Here's a picture that could be helpful in considering this is a possibility just for the fun of imagining it:

 

[RockDoc]

Could there be something clogging up your intake tract and preventing flow to the head? (rodent nest in air cleaner?) Throttle plate is open for the test?

 

[terrx]

When I took the air cleaner and intake tube off to get at the plug wires/holes it was clean.

Forgot to mention, I got a loaner compression guage from O'Reilly's and is was the same result. Probably is time to fork out $ for a leak-down tester.

 

[terrx]

Not that O'Reilly's loaners are high quality by any means, but it was brand new.

 

[scottryana]

How are you going to do a leak down test if you can't get pressure??

Pull the valve cover and take a look.

When I took the air cleaner and intake tube off to get at the plug wires/holes it was clean.

Forgot to mention, I got a loaner compression guage from O'Reilly's and is was the same result. Probably is time to fork out $ for a leak-down tester.

 

[vegasfj40]

Can you reinstall the plugs and post a video of you trying to start? Keep the starter engaged for 5 to 10 seconds.

 

[vegasfj40]

Put everything back together also. Then post a video of you trying to start it.

 

[terrx]

@scottryana , you're right, that's a good point. Pulling the valve cover make sense. Thanks.

@vegasfj40 - I took video on my phone when running the compression test. I'll post it up later when I get a chance.

Thanks a bunch to everyone - I really appreciate the input !

 

[ZackR]

Perhaps lawn mower syndrome...... cylinder walls washed down with fuel resulting in lost compression. The term comes from moving the vehicle a short distance to get the lawnmower out of the garage and then turning it off, while still in a rich cold start mode. The symptom is an engine that is easy to crank over (low compression), kind of like when you crank over an engine when the spark plugs are removed.

I've had this happen before (on several vehicles) when starting the vehicle and moving it a very short distance then shutting it off.

The "cure" is to have a fully charged battery, then crank it over with the throttle wide open for 30sec+, it will sputter and struggle and then roar to life with a cloud of black (rich) smoke. Run it at 1500-2000rpm for a few minutes until it clears out a bit then go for a drive to fully warm things up.

 

[flintknapper]

Perhaps lawn mower syndrome...... cylinder walls washed down with fuel resulting in lost compression. The term comes from moving the vehicle a short distance to get the lawnmower out of the garage and then turning it off, while still in a rich cold start mode. The symptom is an engine that is easy to crank over (low compression), kind of like when you crank over an engine when the spark plugs are removed.

I've had this happen before (on several vehicles) when starting the vehicle and moving it a very short distance then shutting it off.

The "cure" is to have a fully charged battery, then crank it over with the throttle wide open for 30sec+, it will sputter and struggle and then roar to life with a cloud of black (rich) smoke. Run it at 1500-2000rpm for a few minutes until it clears out a bit then go for a drive to fully warm things up.

^^^^^

This is my thought as well. Before reinstalling all the spark plugs...the OP could bring the #1 cylinder a bit shy of TDC. Pour a couple of ounces of a lightweight oil (Marvel Mystery Oil) down that spark plug hole and then crank the engine. The oil should create a good enough seal around the rings to create compression in that cylinder.

The oil will gush out as a mist from the spark plug hole...confirming that mechanically everything is OK. IF that proves out...I'd lightly fog each cylinder, turn the engine over a few revolutions to coat the cylinder walls, put spark plugs back in and start it up.

 

[elhombre]

If there truly is no compressing across all cylinders, you should hear the starter spinning very fast. Should be a noticeable change in sound than what you normally hear. Is this what you mean, "doesn't sound normal"?

 

[1972FJ55]

My 80 had been running fine. Went to start it in the morning after having driven it the night before and it sounded like there was minimal compression. It spun over and tried to start but clearly something was wrong. I didn’t compression test it but brought it to TDC and discovered the timing chain had jumped two teeth. Out came the engine for a rebuild.

 

[terrx]

@1972FJ55 - That was my guess too. I've been running Delo 400 10W-30 (CJ) for about 50K miles with oil changes every 3K. The UOA reports were always excellent, but in what was probably a mistake, the last change just before garaging it I used Mobile 1 5W-20. It sat for 5 months and I tried to start it with a fresh charged battery. I mentioned earlier I don't think it spun more than once before it caught and began to rev. So I wondered if the oil pressure couldn't build fast enough to tension the cam chain before it started.

To answer other folks questions, I think it spins faster now than normal and that's the difference I hear. Also, after maybe 5+ seconds of cranking there's possibly a slight knocking sound.

Also, I don't know if this could have anything to do with it, but it was in a two-car garage and the garage owner jacked her car into the rear bumper. She got confused and went forward/backward multiple times until the side of her car was heavily damaged. I had it in park with the p-brake only lightly set.