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I just started my 2007 GT RX8 Automatic transmission with 13000 miles on new engine replaced by Mazda in 2015. It sat for a little less than 3 years and I decided I wanted to drive it again.. I drained the fuel and replaced fuel pump and put 7 gal of 97 octane fuel with sea foam in it. I also replaced battery,MAF,Plugs,wires,coils because it was running horribly. It idled great but couldn’t rev over 6000 took it to Mazda and had compression test done. The attachment shows test.. now after only 13000 miles they said I need a engine replacement for 12817$. Is there something they may be missing?? I did cheap out on battery and wires but it seemed to idle badly when I parked it and other than that it ran fine. It did get hot before I replaced the radiator but not bad and only a few times. Is there anything I can do other than pay 13 grand to replace engine. This car has 172000miles but only 13000 on engine so I’m very surprised it has already failed Compression test done by Mazda Codes he printed off.
Thats quite the starter if it cranks that fast? Usually its difficult to get it over 300 rpm... that to me makes the rest of the test not valid...
There are a lot of CanBus errors. I would reset the ECU and see which ones come back.
If you replaced it with an aftermarket MAF that isnt a good option... the MAF and the O2 sensor is what allows it to run in closed loop and you have errors for both. You have a MOP fault... that will likely keep it in limp mode and be why it wont rev
Depending on your level of DIY i would and figure it out yourself.... and get a proper comp test..
Thank you for your reply. It will rev like normal for the first 5 or 10 seconds after clearing codes and restarting..I told the mechanic about the limp mode with the OMP and he said that the omp will not limit the rpm’s. I told him I read it would so he said he called someone to verify that and said in no way does it limit any rpm. I know he was wrong but on new engine he quoted a new omp also. This mechanic told me before he even seen or heard or started the car that from what I told him it needs new apex seals. I’m not really convinced it needs a new engine and that the mechanic just didn’t want to or know how to work on it. Also charged 435$ for compression test and diagnostic
Wouldn't be the first time I saw a poorly done compression test from a dealer. Buying your own tester is cheaper and easy to use. Not to mention you can use it whenever you want and know it was done correctly.
Unless the engine was bad from the start, the only other way I could see you lose compression is from the seals rusting to the rotors. After sitting for 3 or so years it could be possible that there is junk in there, but you'd probably see more issues at idle and starting if it was compression. Likely if you could turn, start, and drive the car, then you likely already broke any stuck seals free.
Higher rpm issues I would tend to look for fueling issues. You may have already ruled out a bad fuel pump if you can rev high within the first few seconds. Makes sense to chase down the limp mode route.
Thank you for your reply. It will rev like normal for the first 5 or 10 seconds after clearing codes and restarting..I told the mechanic about the limp mode with the OMP and he said that the omp will not limit the rpm’s. I told him I read it would so he said he called someone to verify that and said in no way does it limit any rpm. I know he was wrong but on new engine he quoted a new omp also. This mechanic told me before he even seen or heard or started the car that from what I told him it needs new apex seals. I’m not really convinced it needs a new engine and that the mechanic just didn’t want to or know how to work on it. Also charged 435$ for compression test and diagnostic
Time for a new mechanic who knows what he's doing.
"apex seals" is what people who don't know rotaries say about rotaries. The engine is about 6k from Mazda. $12k US dollars is bonkers.
I would point them to the Mazda shop manual about the OMP . Or page of 1 limp mode troubleshooting and ask for my money back.
Easy way to tell if it is in limp mode is to reset the ecu... remove the bellows from the throttle body so you can see the throttle plate.... turn the key on... and you should get full range when you pish on the accelerator pedal.
Start the car and the throttle should allow it to rev normally for 5-10 sec... and then the plate will stop responding normally...
Thats the limp mode.that is caused by the MOP. Usually there.is no MOP. Code set...
I would find someplace else to take the car. The compression test should take less than 1 hour of time... and reading the codes... minutes. The mechanic definitely doesnt know what he is talking about if he doesnt know about the MOP limp mode problem
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Kevin,
- How was it driving before sitting ~ 3yrs?
- After starting it, though it ran horribly, did it rev past 6k?
Your "P1687 OMP Motor" CEL will initiate "limp mode", i.e. govern rpms. Perhaps a connector was damaged or left unplugged when your above list of items were replaced. Check OMP wiring, connectors, & operation.
As h/b said... the wildly incorrect rpms indicates "something is off" about the compression test &/or results. That and the exorbitant cost quoted to replace the engine call into question both the aptitude and integrity of said technician / shop. Agreed, I'd go elsewhere.
I'd begin by checking the OMP, i.e. ALL wiring / connectors "touched or disturbed" during any recent work. If required re-compression test. if required investigate approved /reviewed rotary shops for engine replacement or rebuild.
what they said, get a compression tester or find someone close that can lend or help you do it. That’s the first thing. That guy says it’s a non p issue then lists one on his bill lol. If it’s a first series car it may be worth getting a new omp after you check compression.
10-06-2022, 04:16 PM
