Compression test question
marklar88
08-29-2005, 12:00 PM
How long is it necessary to turn the engine over while doing a compression test??? The chiltons manual says 2 or 3 seconds...Does the pressure in the cyliinder keep rising, or is there a max pressure that it will achieve?? Also, what is the compression supposed to be for a 3sgte engine??
91 Celica St
08-29-2005, 07:31 PM
DONT KEEP THE DISTRIBUTOR PLUGGED IN, there should be 2 things from your wiering harness goign to the distributor, TAKE THEM OUT...if not youll damage your distributor
pull the spark plugs and skrew in the comp tester, 2-3 seconds wont be long enoghl, keep doing it untill the pressure wont keep rising, it shoudl just kinda jump up and down a little when its at it highest compression (remember to take all 4 spark plugs out before comp testing too)
you sohuld be around 180-200 on the 3sgte
pull the spark plugs and skrew in the comp tester, 2-3 seconds wont be long enoghl, keep doing it untill the pressure wont keep rising, it shoudl just kinda jump up and down a little when its at it highest compression (remember to take all 4 spark plugs out before comp testing too)
you sohuld be around 180-200 on the 3sgte
marklar88
08-31-2005, 02:36 AM
thanks
91 Celica St
08-31-2005, 03:02 AM
so what were your readings?
marklar88
08-31-2005, 10:13 AM
Well, they were all really low, all of them between 85 and 110 psi. But maybe that is because we were not turning it over for long enough. I just got a new job(now I can actually fund the mods that I want to do) so I dont have any days off in the forseable future, but I am going to have to do the comp. test again properly and then I will let you know the results, thanks trev
toyomechanic421
09-02-2005, 10:14 PM
You should crank it over ten times. You will here it crank slowly and just count ten. Also you must pull your efi fuse so you dont inject any gas into the cylinder. Pull out all the spark plugs, pull your efi fuse, and count ten times for the compression. That is about it.
marklar88
09-03-2005, 01:38 AM
well the first two cylinders were 160ish and the 3rd and 4th were 195-205ish..
91 Celica St
09-03-2005, 03:10 AM
most lekely u jut need a valve job, the comp on mone of my cylinders was low and all it needed was the vavles to be re shimmed and it came out fine
and you dont need to pull the efi fuse, once the 2 plugs on the D cap are disconnected the ecu automatically realizes theres no spark so it wont give and fuel on a celica
and you dont need to pull the efi fuse, once the 2 plugs on the D cap are disconnected the ecu automatically realizes theres no spark so it wont give and fuel on a celica
marklar88
09-04-2005, 11:11 AM
would malfunctioning valves explain why my engine is overheating and spitting overflowing coolant??
91 Celica St
09-04-2005, 06:14 PM
no but a blown headgasket could do those and give you loss of compression
Automotive Network, Inc., Copyright ©2026
