compression test
 

hey guys i am selling my car and the guy that is buying it wants me to perform a compression test first. i called mazda this morn and the guy is quoting me 250-300 bucks. is that right? i think it was like 75 bucks awhile back??? the guy is saying it is quite "involved". are you serious i thought it was as simple as unplugging the spark plugs and hooking something up to it. are these guys gonna hack my car up in addition to charging me $250? anyone have experience in this matter?

also if compression was low wouldnt there be symptons? like low vacuum, poor idle, and smoke at idle and/or acceleration.....?

You might as well just try and drive down to IRP and have them do it if they are open on Sat.

Matty, I know the guy looking to buy your car. Well, not really know as in a friend but a "forum acquaintance" on another forum.

Just warm up the car and do a home compression test using a $20-30 piston engine compression tester. All you are looking to do is to demonstrate to a possible buyer that the engine is not going to grenade on them. :) I would use a phone or digital camera to video the compression test for each housing which you could then attach to your add for others.

hmm...that sounds like a good alternative. he came down this weekend and liked it. it just needs to pass compression which i am sure it will and its sold. lucky guy for getting this car. i will miss her dearly.

these mazda guys scare the crap out of me in terms of my leaving my car in their care.

Good luck with the sale. That guy is getting a sweet car.



You are not alone there!

tks

does anyone know if symptoms have to be present for a compression related problem. meaning the car idles perfectly, doesnt smoke at all, and pulls great vacuum of 18-20 depending on load like brakes are on or lights etc. i am confident the car is in perfect running order....and the buyer was just here yesterday and he agreed its perfect. i just want him to be comfortable. he has been waiting for this day for a long time. but i must say he lucked out in finding this car....a lot you guys know over the yrs how good this car has been for me. i have always considered it to be a bit of a freak in terms of the numbers it has made.

mahjik...any ideas on which tester to buy? my assumption is that you take a plug out and screw in the tester...its pretty much as simple as that correct? i am way off aren't i?

Glad you found a buyer and if you got the 15,500 that's outstanding in this market :icon_tup:

Warm it up, screw in the tester, take out the EGI relay and unplug the igniter and don't forget to have someone step fully on the gas peddle while turning the ignition.

With only 50k miles and a well maintained car I'd expect 100 psi or better

Matty,

Fritz pretty much nailed it, but here's a link to Kevin's site just for more info:

http://www.rotaryresurrection.com/3r...ion_check.html

I just did this test a month or so ago. I found it easier to test from the bottom plugs from under the car...I used a test gauge I got from Advance Auto Parts. I've seen a few write-ups that said to rip out the schraeder check valve. I was able to just unscrew the schraeder valve. You can check for compression consistancy between rotor chambers. Put the valve back in and check for a max psi to see if it jives with your bounching readings. I'm sure you'll get well over 100. My car has been carefully maintained, has 40k on the original engine and I was at 110 on both rotors, on all faces give or take a few psi. Pleasantly surprised to say the least.

can anyone provide a link on a how to? tks

If you look two posts above yours, it's right there cowboy :icon_tup:

Reading posts is so overrated these days