Solidtrance

iTrader: (2)

To the OP (thawk97), PM me before you take it in. I have some insight to whwqt dealership you should use to avoid any hassle. I suspect I may be going through this process soon.

tza0001

iTrader: (2)

How do your plugs and coils look like? Have you ever changed them? If they are in bad condition might affect your compression numbers.

thawk97

My plugs are about 10,000 miles old and my coils about 15k. Just curious, but why would plugs make a compression difference? When one is testing compression, the plug isn't even in the rotor (because the compression reader is) so how would that make a difference if low compression isn't detected while driving but observed through test results?

thawk97

Oh yeah, missed the posts at the end of page 1:

Ryan at Shook Motorsports in Rockford IL did the compression test using one of the TR-01 testers that a guy on here developed but is no longer selling.

tza0001

iTrader: (2)

Many poeple on the forum report that the dealership before running compression tests changes plugs, wires, and coils. Further, the dealership might ask to change the starter for the cars who do not have the upgraded starter to produce the right rpms (people have reported this as well).
To run the compression test aren't you supposed to crank the engine for a few seconds? Thus, I assume that plugs, coils, and wires (transfer the energy) should have some correlation with compression numbers. Does this make sense or I got it wrong? Apologisies if not correct

While trying to find some info to back up my assumptions (habit from getting my Ph.D.) found this post. It is very educating and might be interesting to some.
https://www.rx8club.com/showpost.php...6&postcount=41

Jon316G

iTrader: (1)

Yes... a good 5sec is all thats needed.

Nope.
When you perform a compression test you need to disconnect the eccentric shaft positioning sensor and remove the fuel pump fuse.
Doing this will keep the vehicle from adding fuel and sparking the ignition.
So they can swap any part of the ignition system they want... its not going to affect the compression test whatsoever.

tza0001

iTrader: (2)

You are always helpful. Thanks for correcting me and helping me understand

olddragger

iTrader: (3)

for confirmation also take some vacum readings?

thawk97

That's not something I've even looked into yet - can it be done at home? Need to go use the search function a bit...

Evilnissan

New to me 05 6speed with 72K on the orginal motor so I took it to the local dealer for a compresson test.

Rotor 1
695
694
680

Rotor2
682
681
680

Looks like the faces on the rear rotor are close to the lower limit.

I have no starting issues and only some surging on the upper end of the revs so it looks like a new plugs and coils are in need.