Please Help this Mechanic
Thread Starter
Cruising
Joined: Apr 2006
Posts: 11
Likes: 0
From: El Segundo Ca
Please Help this Mechanic
I'm the original owner of a 1989 Corvette with 35 k on the odometer. It
went in the shop because of rough running while cold and once warmed up it smoothed out. In the shop it received a valve job..timing chain
the master computer replaced...various sensors replaced / fuel injectors cleaned and replaced fuel pump checked filter replaced
ground lugs cleaned etc etc... Okay I've taken my loss
and paid this mechanic for his servicesand the car is now again in my possession. It's worse than
ever...As of this revision to the post 4.23 06..when cold the car runs somewhat okay..it's rough...but when it gets up to operating temperature 215...it sounds as if its going to come apart internally..
It rattles and rocks like I've never heard before..Could there be something atached to the clutch that has come loose...and thus
causing the engine to become out of balance.. Help..Suggestions
on getting a good Corvette Mechanic in So Cal south bay?
went in the shop because of rough running while cold and once warmed up it smoothed out. In the shop it received a valve job..timing chain
the master computer replaced...various sensors replaced / fuel injectors cleaned and replaced fuel pump checked filter replaced
ground lugs cleaned etc etc... Okay I've taken my loss
and paid this mechanic for his servicesand the car is now again in my possession. It's worse than
ever...As of this revision to the post 4.23 06..when cold the car runs somewhat okay..it's rough...but when it gets up to operating temperature 215...it sounds as if its going to come apart internally..
It rattles and rocks like I've never heard before..Could there be something atached to the clutch that has come loose...and thus
causing the engine to become out of balance.. Help..Suggestions
on getting a good Corvette Mechanic in So Cal south bay?
Last edited by Corbird; Apr 23, 2006 at 03:18 PM.
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
If it is an internal engine noise, you could start disconnecting 1 spark plug wire at a time. This will take some of the load off each piston. It may help you figure out which cylinder is out of whack. Then you could further diagnose.
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Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
I'd forget helping this mechanic and cut your losses. They sure have thrown a ton of parts and labor at a car with low mileage and a minor driveability problem. Me-thinks this guy is an incompetent boob, a scoundrel or both.
Drifting
Joined: May 1999
Posts: 1,478
Likes: 3
From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
Originally Posted by Corbird
I'm the original owner of a 1989 Corvette with 35 k on the odometer. It went in the shop because of rough running while cold and once warmed up it smoothed out. In the shop it received a valve job..timing chain
the master computer replaced...various sensors replaced / fuel injectors cleaned and replaced fuel pump checked filter replaced
ground lugs cleaned etc etc....Now I'm being told that the opposite happens and when it gets good and warm 30 to 40 minutes of normal running and driving a strange knock start from inside the right handside of the engine
then the engine starts running really rough. they put
it on the rack and it's not coming from like the crankshaft.
the master computer replaced...various sensors replaced / fuel injectors cleaned and replaced fuel pump checked filter replaced
ground lugs cleaned etc etc....Now I'm being told that the opposite happens and when it gets good and warm 30 to 40 minutes of normal running and driving a strange knock start from inside the right handside of the engine
then the engine starts running really rough. they put
it on the rack and it's not coming from like the crankshaft.
Most of the injector specialists recomment NOT cleaning the 89 Multec injectors due to their poor build quality to begin with. Your "mechanic" took a low mileage car that worked ok when warm and after replacing a LOT of parts which included a LOT of LABOR charges you still have a problem.
I'd try to find someone who has a quality scan tool to scan the ECM and see what is going on with all the relevant sensors at the time the problems appear. The root cause could be anything, but most mechanical problems don't usually wait 30-40 minutes to show up. Electrical issues that are heat dependent often do. It could be something mechanical that requires the oil to be thin enough or the coolant to be warm enough to show up. More likely it is an injector, or one of the replaced sensors that is heat affected due to incorrect installation.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Originally Posted by Mike_88Z51
It sounds to me like your "mechanic" did not use a scan tool properly and diagnose the problem, but just used a parts shotgun approach with you paying for the shot.
Most of the injector specialists recomment NOT cleaning the 89 Multec injectors due to their poor build quality to begin with. Your "mechanic" took a low mileage car that worked ok when warm and after replacing a LOT of parts which included a LOT of LABOR charges you still have a problem.
I'd try to find someone who has a quality scan tool to scan the ECM and see what is going on with all the relevant sensors at the time the problems appear. The root cause could be anything, but most mechanical problems don't usually wait 30-40 minutes to show up. Electrical issues that are heat dependent often do. It could be something mechanical that requires the oil to be thin enough or the coolant to be warm enough to show up. More likely it is an injector, or one of the replaced sensors that is heat affected due to incorrect installation.
with MIke, These are all pretty much guesses. Without actually being there to hear it and know where its coming from is anyones guess. A good mechanic would be able to pinpoint this with the car in front of him.
Last edited by RRT vette; Apr 22, 2006 at 11:01 AM.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
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From: seattle WA
I don't think it's rod,or main bearings, or wrist pin-simply because of the way it runs, I've had problems with those components-made a hellava lot of noise, but didn't really affect how the motor ran-unless it blew 
. It could be a lifter-but if it weren't there before your mechanic worked on it-I'd lean toward another problem-I'd sure wonder about valve lash.
. It could be a lifter-but if it weren't there before your mechanic worked on it-I'd lean toward another problem-I'd sure wonder about valve lash.
- 1986 Original Owner -
Joined: Apr 1999
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From: North Yorkshire, England
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Originally Posted by Corbird
This mechanic has called in some of the top chevy mechanics
in the area...
in the area...
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
in over 40 years of playing with sbc's, i have seen 2 that started to make a substantial ''knock'' after running for more than 30 minutes...both were 100k+ miles with (discovered when heads were pulled) extreme carbon build-up on piston top....removal of carbon cured both (do this only with solvent--do NOT scrape)...theory is that connecting rods expanded with heat soak and deck clearance went negative....your low mileage does not fit this scenario, but if the new head gaskets were thinner than old ones, its a distant possibile cause (but we're really distant here, reaching way down)
like others, i am very uncomfortable with the repairs which were deemed ''necessary'' for such a low mileage vehicle,tho
like others, i am very uncomfortable with the repairs which were deemed ''necessary'' for such a low mileage vehicle,tho
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by Corbird
I'm the original owner of a 1989 Corvette with 35 k on the odometer. It
went in the shop because of rough running while cold and once warmed up it smoothed out. In the shop it received a valve job..timing chain
the master computer replaced...various sensors replaced / fuel injectors cleaned and replaced fuel pump checked filter replaced
ground lugs cleaned etc etc....
went in the shop because of rough running while cold and once warmed up it smoothed out. In the shop it received a valve job..timing chain
the master computer replaced...various sensors replaced / fuel injectors cleaned and replaced fuel pump checked filter replaced
ground lugs cleaned etc etc....
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by Corvette Kid NC
Just curious, have you asked this parts-changing bandit what was his reason was for doing things such as a valve job, timing set replacement, ECM replacement, multiple sensors, etc. on a low-mileage car with such a minor problem?
What were the wet and dry compression test readings or the cylinder leakage test results BEFORE he decided to do a valve job?
Noises CAN be difficult to pin down, but if "some of the top chevy mechanics in the area... say they've never heard anything like this before..", you aren't going to get anything from the forum, where we can't hear it, is maybe, a lucky guess.
Based on what YOU'VE posted, *I* am of the opinion that you have been screwed blue and tattooed nude. Sorry.
RACE ON!!!