Compression Test help
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Compression Test help
I have a slight miss that i was trying to troubleshoot. I was in the process of changing wires and plugs so I figured I'd do a comp test. I've done the following, as posted in another thread I've found (except I have a large screwdriver in the tb since its a DBW). I did this on 3 cylinders already and dont get anything over 30psi then drop to 0. I doubt all three are bad since I've been driving the truck daily and it hasnt been giving me problems. I rented a tool from Auto Zone.
Remove all spark plugs, remove fuel pump relay, unplug both coil pack connectors. Screw hose with correct end(it will match spark plug threads) into spark plug hole and connect the gauge. Read the gauge while somebody cranks the engine for you. While they are cranking, they should have the throttle slightly cracked open. Let the engine spin three times(the gauge will jump 3 increments) and that is your reading.
Last edited by Hawaiian_Built; 07-14-2012 at 10:01 PM.
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i was getting about the same results on my truck after doing a full engine rebuild... turned out there wasnt enough oil on the rings and it was getting blow by since i had cranked it for so long without it firin (ground wire to computer wasnt connected) but after getting it to start i tested it again and there was 175+.. try starting it and letting it run for a bit then try the compression test again.. you could have dumped to much fuel into the cylinders and effectivly cleaned the oil from the rings
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i was getting about the same results on my truck after doing a full engine rebuild... turned out there wasnt enough oil on the rings and it was getting blow by since i had cranked it for so long without it firin (ground wire to computer wasnt connected) but after getting it to start i tested it again and there was 175+.. try starting it and letting it run for a bit then try the compression test again.. you could have dumped to much fuel into the cylinders and effectivly cleaned the oil from the rings