kennycoulter

well, i only have my mustang book here at the apartment, and according to that, i didnt fully do the test. from cylinder number 1-4:189, 191,90!!!!,190. then i retested number 3 and it raised to 110. according to my mustang books, i am supposed to have the engine at operating temp, block the throttle, and disconnect the coil, and turn and watch the gauge. i didnt want to burn myself, so i did it cold, and i didnt block the throttle open, i disconnected the coil and undid all the plugs. i also couldnt watch the gauge from the ignition key. supposedly, if i would have put oil in the spark holes and cranked again, if the number rose dramatically: wouldve been worn rings. so mine could be anything. spark plugs according to my manual means too hot!!!! white coating flaking off. any ideas?

kennycoulter

are my other 3 cylinders too high? if they read high its supposed to be high carbon deposits. with the one bad cylinder, its supposed to ba any of a number of things like valves, guides, block, head, head gasket......

hacker-pschorr

WTF, since when did 944/921/924/951/968 include Mustangs?

Why are you doing a compression sheck on a 2003 Mustang? I know Ford's warranty's are not the greatest, but I would hope the car was still covered.

Anyway, I did a test on my 928 both red hot and ice cold (off for 2 months with the intak manifold off) the results were the same.

Luis de Prat

Hacker, don't be so narrow minded. This is a "car enthusiasts" forum, so we should be much more open to discussing other makes and models!

Joking aside, I'm all for helping a fellow 'lister out, but I'll admit this Forum won't get you the best responses, Kenny. I'd try posting this to the OT forum.

Good luck with the car.

MM951

Well, its not like 3 cylincers were warm..I'd check it out...my rule of thumb is if there is a 20psi difference to check it out further

Ken D

I'm guessing that he did a compression test on his 944 but used the Mustang service manual for the comp test procedure. His Mach 1 is a V8 (although the SVO is a 4-banger).

nine-44

I'd try it again, I've had some read goofy at first and then show perfect every time after. I think the checkvalve in the guage sticks sometimes?

kennycoulter

yes im checking the 944 that ive wanted to check for a while but kept forgtting. i have my mustang book here and the porsche book at my garage. i figured the procedure should be the same. i guess ill try again tomorrow after its warm. im taking another car today. and yes i have bosch platinum +4s in. would that be my too hot problem? werent you people suggesting copper plugs from ngk or something like that?

Chris_924s

Bosch Coppers. It's all I trust.

kennycoulter

so pretty cheap and available at wal mart? i get a discount there.

kennycoulter

i bought autolite brand autozone couldnt fing bosch coppers. when i let my car sit for a week this time, i had a lifter tapping!!!!! its not doing it now, but after just a week seems bad, what can i look into for that?

Charlie

I would not put anything but Bosch plugs in the 944. I would test the cylinder again, if it was still low I would put a small amount of oil in the cylinder and see if it makes a difference.

kennycoulter

that means that the rings would be bad though right?

User 41221

Not necessarily. First off, make sure you pull the DME relay and block open the throttle body, and then go do it again. A warm engine will give you a better test, so lets 'er run for a few minutes at least.

If you get the smae results, I would suggest a leakdown test, its a much better way to disagnose problems. Compression tests will indicate that there is a problem, but not necessarily "what" the problem is.

Regards,

StupEd05

Yes, sometimes the check valve does stick. I did a compression test yesterday and it scared the **** out of me cause I got 110,135,140,150. Then I PROPERLY blocked the throttle and that 110 came up to 140 along with the 135. So all is well. Sometimes I will go crank it to get a reading and all I can see is the gauge pumping up and falling right back down, this is that damn check valve sticking.