Brad4g63

Performed a compression test on my 04 6mt GT. 68k miles motor replaced at 42k

Rotor1: T 92.5 psi L 95psi
Rotor2: T 105psi L 105psi

Car has been getting progressively less and less MPG's since summer time, last 3 tanks were 12-13 MPG compared to 18-20 the last 3 years. haven't noticed a loss of power so much, no smoke, starts fine every time, only hiccup is the MPG. I have Plugs, Wires and Coils in the mail and will install Tuesday but the compression test is got me wondering.

now i used an old style compression tester, didn't know there was any other kind. don't have the Mazda unit specified not sure what the difference is besides a graphical display with RPMs.

Performed according to the manual minus the specified tester.

brand new full charged battery and never had any problems with starter.


Now my questions are:

could the compression tester be a cause for the low readings? BTW,Actual purchased SAE tool not some DIY hack job. would the recommended one really provide a more accurate reading?

So im thinking my motor is fried motor was rebuilt april of 2008 at 42xxxmiles 4 months before i purchased the car. anyone know anything about warranty information car was repaired at Suburban Mazda of Troy, Michigan.

Going to call them in the morning would appreciate as much information as possible i am not a fan of dealerships have never had a good experience at one before.



HELP!!!!!

9krpmrx8

iTrader: (46)

You used a piston engine compression tester? Did you remove the check valve or hold the relief valve down? A rotary compression tester is very specific.

vlad0691

iTrader: (1)

You need a rotary specific compression tester so it can take compression on all 3 sides of each rotor.

Brad4g63

yes a piston engine compression tester, did not know there was a difference. The manual i have did not mention anything about a check valve or relief valve. warm motor, unplug Crank position sensor remove plugs on both of chamber to be tested on both rotors hold throttle open and crank for ten seconds. did this for all four plugs and got the previously mentioned results.

so there is a need for a special tester. My question now is would my results and symptoms deem a trip or call to the dealership necessary or would the low pressures be the result of the improper tool?

vlad0691

iTrader: (1)

The figures you got are wrong, there should be three figures per rotor, one for each side. The cheapest way is to go to the dealer and let them do a compression test and bring the results back here to us. If your car is still under the 100k/8yr warranty, the dealer should replace your motor if you fail.

zoomman

how much does a dealer usually charge for a compression test if you're beyond the 100k mark?

StealthTL

iTrader: (1)

how much does a dealer

$193.

Doesn't matter what we say it costs, it 's what the dealer quotes, right?

Phone your friendly neighborhood.......

Brad4g63

Got the test done at the local dealership yesterday. Price was $95 OTD, compared to another dealer that wanted 120 plus 1 hr labor. service tech ranted off the results over the phone it wasnt in Psi so didn't quite catch it but under the minimum specs so Mazda is going to provide me with a new motor. with 1 month to go on the warranty. good timing.

vlad0691

iTrader: (1)

Close one, good to hear. I have 145k miles, so if my motor ever goes, I'm screwed.

Also, the compression test should be free if your car fails I believe.