Mechanics

PONTIAC TRANS AM COMPRESSION PROBLEM

1977 Pontiac Trans Am • 150,000 miles

Just bought 77 t.A. 2 months ago, car hasnt given any indication of any isues, I am an industrial mechanic by trade (weld/fab, elec, hyd) and usually do not have problems finding issues but this one has stumped me. Was spinning wheels in grass in my yard and hit the rev limiter in 1st gear while doing so, the next day I hit the road and thought I may have fauled a plug, replaced plugs (8) and did not correct the issue. Checked distributer for cracks and button, tested plug wires at spark plugs and all were firing. Getting a small push back at carb. And light ticking at mid rev. Is my issue carb, timing or internal, dont know where to begin on this one
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Crickett069
March 22, 2013.



Is the engine missing? Was it missing after you were spinning? Have you checked to make sure none of the plug wires are arcing?

First, never heard of a rev limiter on any of those models. I used to crank up my gta to 8500 or better.

I would start with a compression test. Then I would remove the valve covers to see the actions of the rocker arms. Did you replace the plugs?

Roy

ASEMaster6371
Mar 22, 2013.
Yeah, engine is missing, yes, I did check wires with tester but not for possible mid body wire arching and I did also replace all 8 plugs, started missing right after taching it up in my yard, may not have rev limiter (thought it did but I could be wrong) first f body ive owned this old! Will idle and drive but very rough, hood shaker moving irratically during idle

Tiny
Crickett069
Mar 22, 2013.
If you have a rough idle (dead miss) use an insulated set of pliers (so you don't get shocked) and remove one plug wire at a time. The engine should miss worse each time you do it. Eventually, you will remove one and there will be no change. That is the cylinder you need to focus on. Check for a good spark to the plug, check compression.

Ok, considered doing this already but wasnt looking forward to the possible shock, fixing to run out side and do this but what is causing the ticking noise at mid range? What should I be looking for at rocker arms as per earlier response

Tiny
Crickett069
Mar 22, 2013.
Equal movement of all arms. I suspect either a cam or lifter issue with the tapping.

As Joe stated do a compression test first.

Roy

ASEMaster6371
Mar 22, 2013.
Ok, sorry for the delay, checked for dead miss and found no issues, went ahead and replaced wires (they were very old), borrowed compression gauge and found 2 cylinders with only 15 to 20 psi (drivers side- middle 2 cylinders), all the rest were 125 to 135 psi! What does this mean?

Tiny
Crickett069
Mar 23, 2013.