Compression Test - FAILED....what now?
#1
Compression Test - FAILED....what now?
Hey Guys,
Just got my first 8 (and first rotary) 2 months ago. 2007 w/ 13,900 miles. I have 1 month left on the powertrain warranty so I decided to have a compression test performed. The results are:
R1: L 95-psi T 95 psi
R2: L 95+psi T 95+psi
These tests are not from a dealer (nearest one is 2 hours away) but rather a local import repair shop.
The tech tells me the staandard compression should be around 120 psi with a minimum of 98.6 psi. He said the test was run between 250-270 rpm.
My current highway gas mileage is at 19.5mpg at speeds between 80 - 85 mph. (seems a bit low)
I have done some searching on here and havent found anyone with similar results so forgive me if this has been covered (but I just havent found it).
Obviously, i'm going to have to make the 2 hour trip to the nearest dealer but i'd like to get your guy's expert opinions on what my best way is to approach this. I'm assuming failing a compression test with this low mileage is not good at all and I should try to get the dealer to put in a new engine.
Everything on the car is stock. I know that replacing the coils, plugs and possibly a decarb will help but is that just putting a band aid on an inevitable engine failure some day?
Any advice would be much appreciated. Thanks.
Just got my first 8 (and first rotary) 2 months ago. 2007 w/ 13,900 miles. I have 1 month left on the powertrain warranty so I decided to have a compression test performed. The results are:
R1: L 95-psi T 95 psi
R2: L 95+psi T 95+psi
These tests are not from a dealer (nearest one is 2 hours away) but rather a local import repair shop.
The tech tells me the staandard compression should be around 120 psi with a minimum of 98.6 psi. He said the test was run between 250-270 rpm.
My current highway gas mileage is at 19.5mpg at speeds between 80 - 85 mph. (seems a bit low)
I have done some searching on here and havent found anyone with similar results so forgive me if this has been covered (but I just havent found it).
Obviously, i'm going to have to make the 2 hour trip to the nearest dealer but i'd like to get your guy's expert opinions on what my best way is to approach this. I'm assuming failing a compression test with this low mileage is not good at all and I should try to get the dealer to put in a new engine.
Everything on the car is stock. I know that replacing the coils, plugs and possibly a decarb will help but is that just putting a band aid on an inevitable engine failure some day?
Any advice would be much appreciated. Thanks.
#2
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Low compression at 13,000 miles is very low, and a bit of a cause for concern, although it's possible that the test was done incorrectly, which is more possible because the results aren't in the format really needed. You need 7 total numbers, possibly 8. You need a compression score for each face of each rotor (3 for each rotor), plus a crank RPM. Rarely does the crank RPM shift from one rotor to the next, so usually 1 RPM number is sufficient, though sometimes the RPM for each rotor is given.
Ignition health won't affect the compression scores however.
Your best bet is to just go to the dealer, ask for a compression test, and then go from there. Even if your engine is just fine, it's a peace of mind thing that is very much worth the cost of time and travel to get there and the cost of the test. It's not something you want to pass up on and find out you REALLY should have.
Ignition health won't affect the compression scores however.
Your best bet is to just go to the dealer, ask for a compression test, and then go from there. Even if your engine is just fine, it's a peace of mind thing that is very much worth the cost of time and travel to get there and the cost of the test. It's not something you want to pass up on and find out you REALLY should have.
#4
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Your results should look like:
Rotor 1: 7.2, 7.1, 7.1
Rotor 2: 7.3, 7.4, 7.1
@250rpm
Actual numbers may vary obviously.
The 250 rpm is important, the Mazda compression tester should be able to convert the result it sees at whatever rpm they test at to what it should be @250 rpm
Rotor 1: 7.2, 7.1, 7.1
Rotor 2: 7.3, 7.4, 7.1
@250rpm
Actual numbers may vary obviously.
The 250 rpm is important, the Mazda compression tester should be able to convert the result it sees at whatever rpm they test at to what it should be @250 rpm
#10
Your results should look like:
Rotor 1: 7.2, 7.1, 7.1
Rotor 2: 7.3, 7.4, 7.1
@250rpm
Actual numbers may vary obviously.
The 250 rpm is important, the Mazda compression tester should be able to convert the result it sees at whatever rpm they test at to what it should be @250 rpm
Rotor 1: 7.2, 7.1, 7.1
Rotor 2: 7.3, 7.4, 7.1
@250rpm
Actual numbers may vary obviously.
The 250 rpm is important, the Mazda compression tester should be able to convert the result it sees at whatever rpm they test at to what it should be @250 rpm
#11
Well, here are the results.
Rotor 1: 6.7, 6.7, 6.7 @ 293 rpm
Rotor 2: 6.8, 6.7, 6.5 @ 306 rpm
The Mazda dealership claims that these numbers pass. From the graphs I have seen I believe they do not pass. Any help?
Rotor 1: 6.7, 6.7, 6.7 @ 293 rpm
Rotor 2: 6.8, 6.7, 6.5 @ 306 rpm
The Mazda dealership claims that these numbers pass. From the graphs I have seen I believe they do not pass. Any help?
#12
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Correct me if i'm wrong.
Any number below 7 (even if it's just one), means you need a new motor.
Get all your oil change records ready, you'll need those in order to get you a new motor.
Any number below 7 (even if it's just one), means you need a new motor.
Get all your oil change records ready, you'll need those in order to get you a new motor.
Last edited by ShinkaEvo; 10-15-2012 at 07:30 PM.
#14
Out of NYC
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Just look at this
if 98.6psi/680 KPa @ 250 rpm is BARE minimum. How the F can you pass when you are getting those numbers @ almost 300 rpm? with numbers like yours, it will put you to the low 6/high 5s @ 250 rpm.
Last edited by nycgps; 10-15-2012 at 10:20 PM.
#17
By any long shot of a chance.......Does anyone have a good contact person they have dealt with at Mazda North America?
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That's mine when I got it replaced last year. Rotor 1 is at low, while rotor 2 is way below the minimum, you can see on the right-most column where it says 'standard' and minimum' since yours is below minimum; tell your dealership/ mechanic/ service adviser --> you don't a lawyer or English teacher to tell you what it means when it's below average. They should get it Warrantied FOC.
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