Cyl. Cont. Test various results???
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Freshman User
Joined: Jul 2006
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Cyl. Cont. Test various results???
Okay I have been trying to figure out a problem with my truck. Which led me to using a nice fancy Snap-on scanner on it. Well after figuring out my CPS is only working intermittently (SP?) I came upon other issues.
I ran a cylinder contribution test the other day and it came back and told me there was a fault on cyl #4. Then today I brought my truck to another buddy and he ran it with a newer snap-on scanner and this time it read a fault on cyl #7. Sooooo.... after my long drive home I decided to throw the scanner back on it one more time. This time it read faults on cyl 4, 5, and 7. At first I was going to start replacing injectors, but the varying results make me think it might be an issue somewhere else... any suggestions??
Oh yeah... also when I run the test with truck in park it will come back as a system pass. However I read on here someone mentioned to put the truck in drive with the brakes applied. When I do the test in drive is when I am pulling the faults.
Thank you all greatly!
I ran a cylinder contribution test the other day and it came back and told me there was a fault on cyl #4. Then today I brought my truck to another buddy and he ran it with a newer snap-on scanner and this time it read a fault on cyl #7. Sooooo.... after my long drive home I decided to throw the scanner back on it one more time. This time it read faults on cyl 4, 5, and 7. At first I was going to start replacing injectors, but the varying results make me think it might be an issue somewhere else... any suggestions??
Oh yeah... also when I run the test with truck in park it will come back as a system pass. However I read on here someone mentioned to put the truck in drive with the brakes applied. When I do the test in drive is when I am pulling the faults.
Thank you all greatly!
Post Fiend
Joined: Oct 2003
Posts: 5,903
Likes: 1
From: MICHIGAN
Cylinder Contribution Tests can be like that if you have an intermittent problem to begin with. I run CCT's in park....with the engine screaming hot. I hook up the scanner, go for a hard ride, usually recording, then stop and run a CCT...repeat, That's about the only way I can get a repeatable test. Get a recording scanner on it and go for a ride until the trouble surfaces.
