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Doc Automotive
Doc Automotive, ASE Certified Technician
Category: Car
Satisfied Customers: 275
Experience:  ASE Re-Certified Technician/Advanced Automotive Diagnostic Technician/27 yrs.Experience,All Makes
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2000 Pontiac Grand prix: ticking noise..valves..lifters..injectors

Resolved Question:

I have a 2000 Pontiac Grand Prix 3.8. There is a ticking noise on the top end of the motor. I have repaced valves and spings, lifters and injectors. The car runs excellent, but it has a slight miss. The check engine light is on and the code is misfire on #1 cylinder. Also has new plugs and wires. At 30 mph the light starts flashing steady. Anything below 30 it is on steady. The cylinder had no compression until I changed valves and springs. It now has 180lbs but is still ticking. Any clue what is causing the ticking?
Submitted: 9 years ago.
Category: Car
Expert:  Doc Automotive replied 9 years ago.
Hi, Doc here, GM expert. There is probably carbon build up on the back of one of the valves, or there is a lifter that is loosing pressure.
Customer: replied 9 years ago.
Reply to Doctor Automotive's Post: I have already replaced the valves and lifters. There is no car.bpn build up
Expert:  Doc Automotive replied 9 years ago.
Then apparently the valve installed height is wrong.
Customer: replied 9 years ago.
Reply to Doctor Automotive's Post: The valves and springs were professionally done. They be seated to the right height.
Expert:  Doc Automotive replied 9 years ago.
Did you check the installed height yourself? The only other alternative is a worn cam lobe.
Customer: replied 9 years ago.
What should the valve height be?
Expert:  Doc Automotive replied 9 years ago.
That would be 1.935 to1.975 for both intake and exhaust. Tough to check without an installed height tool, but can be done.
Customer: replied 9 years ago.
How do you check without tool?
Expert:  Doc Automotive replied 9 years ago.
I'd use a dial indicator.. If you don't have a dial indicator, ust a combination of flat rulers, one top to bottom on the valve spring seat, and the other one across the tip of the valve. Or, ask your machine shop to either borrow theirs, or come out and check it.
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