NotAPreppie

Just got a compression test done on my '05 MT with 49k miles.

Rotor 1
8.7 kgf/cm^2
8.0 kgf/cm^2
8.4 kgf/cm^2
354 RPM

Rotor 2
8.1 kgf/cm^2
8.1 kgf/cm^2
8.3 kgf/cm^2
361 RPM

Now my question... Do I just have the strongest starter ever? Going through various compression test results, don't remember seeing any quite this high. I'm wondering if the technician typed in a "3" instead of a "2" for the first number. Most charts don't seem to go up past 300 or 320 RPM.

Loki

iTrader: (1)

Maybe he performed the test with all spark plugs pulled out, so the starter wasn't fighting compression?

Lookalike

I had the compression checked on my 2006 and the starter was turning around 330rpm on the first rotor test, and 310 on the second. My battery is an optima red top that's a few months old, and I believe I read here the starter on 06 are stronger then previous years. Even though these RPM don't appear on most charts, Mazda's software is able to cross reference these RPM and see if the compression is good or not.

9krpmrx8

iTrader: (46)

No S1 starter should be spinning that high unless, like what loki said. I have a brand new S2 starter and battery on mine and it was close to 300RPM on each test which is about normal for a S2 starter. We have done a few tests with guys with S2 starters and new batteries, they are all about the same from 290-300RPM. This is using our Rotary Diagnostics tester, a twisted rotors one, and a dealer tester. We were using all three to compare.

I have seen many dealer tests and never over 300RPM so I call BS or the test wasn't done right.

NotAPreppie

The battery is new-ish and starter was replaced under warranty in 2008/2009 (I'd have to find my notes to remember exactly when) after I complained about long starts during that bitter cold winter.

I called the service adviser and asked him to verify that the tech didn't fat-finger the keys when he was entering them. Wonder how long before he calls back (if ever).

If those are supposed to be 254/261 then my engine isn't awful shape (hot starts and idles fine). If it's genuinely 354/361 then I'm going to have to put some plans on hold and start shopping around for a reman engine.

9krpmrx8

iTrader: (46)

Honestly if the dealer test was done right then the tech should not have had to enter anything. The dealer compression tester gets hooked up to the WDS (or a dealer laptop running the software) and the results are calculated and then you can view them or print them out.

Which is why I always tell people there should be no reason they should get hand written results.

NotAPreppie

Finally got my hands on a scanner. Here's the sheet stapled to the back of the work order.

Still waiting to hear back from the service adviser.

nycgps

iTrader: (1)

those numbers are failed

NotAPreppie

Well, the SA spoke to the tech and they are standing by the reported RPM numbers (insane though they may be).

The obnoxious thing is that the cost of one compression test is a significant % of the purchase price of a compression tester.

Steve Dallas

^ How much did you pay? The closest dealer to me wants $275. There are cheaper alternatives in the area, but I'm shocked that they want 3 hours labor to do something that takes less than 1 hour.

Loki

iTrader: (1)

Doesn't the shop manual provide a par time for the test (like every other procedure)?
I'm curious how they justify the extra 2 hours.

@OP: you could make good money if you have a comp tester and a steady stream of local clientele who don't want to pay the dealer.

9krpmrx8

iTrader: (46)

My buddy had to bring in the FSM to the dealer in Austin he went to and go over how to do the test on his engine because they did it wrong. Remember most dealer techs are idiots.

And yes loki, they cannot just make up a number, if they are price gouging then report it to Mazda USA. The test had a set job time and my buddy who worked as a tech would do mine in like five minutes using the factory tester and computer, he didn't even have to jack up.

nycgps

iTrader: (1)

yep, I did all my compression test with the car sits on ground. it's a bit hot tho and I burnt myself couple of times