Proper Procedure for Compression Test : 2.7L V6

I'm no expert, so someone else will have to chime in. The 2.7L plug holes are recessed several inches, so the compression tester needs to be able to reach (do they make exensions since several engines are like that these days?). Something else (and again I'm no expert - just something I observed about 10 years ago) - it came into vogue to, instead of doing a compression test, to do what's called a "cylinder balance" test. That's where you disable one cylinder at a time at idle and record the rpm drop - a weak cylinder was indicated by not much of a drop compared to the others. But I'm sure you can still buy compression gages.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Thanks Bill. Yes they make extensions for the compression testers. They generally come with a 15" hose.

Since I wrote the original question I've been thinking that I'll have all the plugs out during the test (good, since I have to change them anyway), I'll have to disconnect the LV wiring to each of coils so I don't damage those, and I'll have to prevent fuel from being pumped into the injectors while turning the engine over. I'm not sure yet how to do that part.

Besides curiosity, the purpose of this is see if running a couple of Auto-Rx treatments makes any real difference to the compression; it has for many users.

Phil

Bill Putney wrote:

On the LH cars, lookng at my '99 FSM, it's real simple - PDC Fuse S (20 amp) supplies power to the coils and the injectors and nothing else. Just pull that fuse. You didn't say what vehicle this is on, but I suspect they used the same power distribution philosophy on all other late model vehicles.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Thanks Bill. It's a 2001 Intrepid.

I'll check the legend in the cover of my PDC to see if the same fuse will kill fuel and coil power in mine. If so, that makes life a lot easier.

Thanks aga> Phil T wrote:

You're welcome.

I also have a 2002 FSM - I just checked and it shows the exact same thing (fuse 'S' for coils and injectors), so you're pretty safe to assume that's how your '01 is. With very few exceptions, the power distribution stayed the same thru the 2nd gen. LH car run.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Huh?? I don't recall him saying that there's any problem - he's just curious about compression after using an additive.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')