1st cylinder not firing after valve cover gasket replacement (1 Viewer)

Joined
Mar 30, 2011
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Hello all

I recently took my 93 fzj80 in for a valve cover gasket replacement and afterward the vehicle was surging at stoplights. The shop took it back and said they think something may be blocking the exhaust valve in the 1st cylinder, that is is leaking about 85% of the air in the cylinder and that they can take it apart and send it to a machine shop for $1,500. That was about 500 miles ago. The CEL is still on and it still surges/shudders at certain RPMs.

They don't believe they caused the problem.

My question is with the engine at 225k miles should I pay $1500 to have this fixed or should I just pay the going rate for a rebuilt engine (and from who?) or what would you do? I mean, if they are taking the engine out should I do more than just get this one cylinder fixed?

I am in Western Colorado, I've had the birfields replaced and have an OME shock/strut kit so it rides pretty nice usually.

TY
 

flintknapper

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Hello all

I recently took my 93 fzj80 in for a valve cover gasket replacement and afterward the vehicle was surging at stoplights. The shop took it back and said they think something may be blocking the exhaust valve in the 1st cylinder, that is is leaking about 85% of the air in the cylinder and that they can take it apart and send it to a machine shop for $1,500. That was about 500 miles ago. The CEL is still on and it still surges/shudders at certain RPMs.

They don't believe they caused the problem.

My question is with the engine at 225k miles should I pay $1500 to have this fixed or should I just pay the going rate for a rebuilt engine (and from who?) or what would you do? I mean, if they are taking the engine out should I do more than just get this one cylinder fixed?

I am in Western Colorado, I've had the birfields replaced and have an OME shock/strut kit so it rides pretty nice usually.

TY

You shouldn't need a rebuilt engine at that mileage. IF that cylinder truly is leaking and it wasn't before.....odds are they dropped something into the head and don't want to admit it. IF the head needs service, the engine doesn't need to come out.

You might consider having a trusted mechanic do a complete compression and leak down test on the head/cylinders and go from there.
 
Joined
Mar 30, 2011
Messages
31
You shouldn't need a rebuilt engine at that mileage. IF that cylinder truly is leaking and it wasn't before.....odds are they dropped something into the head and don't want to admit it. IF the head needs service, the engine doesn't need to come out.

You might consider having a trusted mechanic do a complete compression and leak down test on the head/cylinders and go from there.

Thanks for the tips. Yeah I thought this was my trusted mechanic but I don't want to take it back there now. Actually there is a right hand drive 97 cruiser that moved in down the street recently maybe I'll see if they know anyone.
 
Joined
May 13, 2012
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Seattle, WA/ Jacksonville, OR
If I read this right; you drove your truck there with no issues, and now it is misfiring and supposedly has high leakdown? These things don't generally just pop up right after a repair in the same area. I believe there was a thread on here where someone did a valve cover gasket and was convinced their PCM was bad afterward. Turns out he just pinched the harness in the valve cover. I'd get a second opinion from another source that is non-biased.
 
Joined
Mar 30, 2011
Messages
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If I read this right; you drove your truck there with no issues, and now it is misfiring and supposedly has high leakdown? These things don't generally just pop up right after a repair in the same area. I believe there was a thread on here where someone did a valve cover gasket and was convinced their PCM was bad afterward. Turns out he just pinched the harness in the valve cover. I'd get a second opinion from another source that is non-biased.
Yes. Engine has been smooth for years, immediately after valve cover gasket replacement (on the way home at 5pm on a Friday nonetheless) it chug chug chugs at idle. For a second I thought I had a diesel.

I'm looking around the forums for a lead on a new mechanic.
 
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Jun 11, 2018
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Colorado
There's also the pesky PCV valve mount (normally replaced during this sort of procedure) that usually divests itself of material directly into the hidden area inside the valve cover. If not flushed out, that material can fall down into the top of the head and possibly cause issues in the valve train. Tho it is made of plastic I would think it would be melted and burned away pretty quickly in or around an exhaust valve.
The o'le "it wasn't doing it before you touched it" argument with a shop is such a drag. I learned my lesson with a tranny rebuild, so now I always have the mech who intends to work on it drive it around and comprehend its running status prior to any further work. And simply say, "I expect all this to be the same when you're done." lol
 
Joined
Mar 30, 2011
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Heard back from mechanic that the cylinder is only leaking 10% and that the problem is most likely the injector wire frayed or split somewhere along the line. That sounds a lot better than taking the engine apart.
 
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Olathe, KS, USA
Heard back from mechanic that the cylinder is only leaking 10% and that the problem is most likely the injector wire frayed or split somewhere along the line. That sounds a lot better than taking the engine apart.
Bet they pinched a wire for an injector in the VC or manhandled the harness near the EGR and it jacked it when doing the VC gasket.
 

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