I purchased an 06 rx8 with 103k miles that looked well taken care of and drove fine on test drive. We drove it home 20 highway miles and filled up before going home. The next morning my son drove to school and after 12 miles on the highway got off exit and came to a stop. When he tried to accelerate from stop, the car stumbled and wouldn't go above 1500 rpm. He pulled over at a gas station and called me. I suspected bad gas from the night before and had him add 2 bottles of heet to gas tank. He let it set for an hour or so and I had him drive it to the mazda dealer for diagnostic. Dealer called me later and said the car had low compression and needed a new engine as well as plugs, wires, and coil packs. I can see plugs and wires cause they wires look original and plugs dont look very new. Can this dealer be blowing smoke trying to milk me? I picked up the car and told him I would sleep on it. I drove it home and had no problems except one little stumble at a light after the vehicle warmed up. To me that sounds like wires and or plugs. Thinking of taking it to another dealer without letting on and having them do a compression check.Any help would be much appreciated.

 

Don't know much about rotary engines, but i would re-set or re-flash the ecu. 100,000 miles would require new wires, ign coils. Without knowing service history it's probably a good idea to change plugs as well. Clean throttle body, maf, egr valve. If it has a PCV valve change it.

 

One of the reasons I think the low compression test might be bull is, the car starts right up especially if warm. Also, it runs like a raped ape. The odle sounds smooth but if you bring it up to 2000 rpm or so steady you will hear and feel a small stumble. I don`t know rotary engines either but it sounds like plugs and wires to me. Maybe a coil pack or 2.

 

I was thinking about this all night, Driving me nuts. When I got home and was looking the engine over in my garage, it looked to me like the plug wores had never even been touched. Does anyone know which of any plugs have to be removed to do a compression check? Is it normal for them to do a compression check when i took it in for a 79.95 diagnostic test?

 

You cant use a conventional compressor tester. They wont work on a wankel engine. I would guess only a mazda dealership will the correct/proper tester.

 

A diagnostic test is basically them hooking up the computer and checking for codes, history and if sometimes if updates are available. No way would that price include a compression test.

 

Just for a recap, the car was taken to the Mazda dealer for the diagnostic. He says he will put the 80 dollars into the cost of the engine change if I have it done. I wasn't sure if there was some kind of vacuum test he could have done to check compression in the diagnostic test. If he is just assuming that the compression is low, that be a huge assumption and cost to me. Maybe since there have been so many engjne changes on these cars he didn't think it would raise an eyebrow, but this car is out of warranty. 104k.

 

I really think you need to clarify: 1) if a compression test was done and 2) how he came to his conclusion.
Also ask if if that car has been in his shop before and inquire about the history.

 

Thanks for all of the helpful suggestions! I learned alot about my new 06 rx8 this weekend. This car started running like crap the day after I bought it from a private seller, which i believe brought on my flooding issues. I replaced plugs with NGK`s, plug wires with NGK`s and 4 echlin coil packs. The engine was still whirring on first start. I didn`t know if I crapped out a starter or what? It sounde like the engine had no spark or compression. I confirmed spark from the new plug wires at the plugs. Next, I proceeded to crank with all 4 plugs removed and battery charger attached so as not to drain battery. I would crank 2 or 3 times for 6 or 7 seconds and then wick out the fuel at each spark plug hole. I must have did that 20 or 30 times until the plug holes were dry after when I would crank. Finally I put the dry plugs back in along with the fuel relay and tried several times with my foot on the floor while cranking. every few times I would hear a little burble and finally I gained the courage to try a normal start with foot off accelerator pedal. SHE STARTED!!!! Ecstacy!!! After all of the smoke cleared with my foot holding 3k rpm or so, I let her idle and installed the tire. The car ran very smooth with excellent acceleration. No problems at all! This is after the service manager at the dealer told me I needed a new engine due to low compression. Oh yea, and by the way, I could tell the plugs were never removed for compression check from the crack I heard and felt when removing the plugs. The were very fouled and believe it or not, there were 4 trailing plugs installed!!!! Now that the car is running so well, I have a hard time thinking she could have low compression. should I even waste my time to have the compression checked at another dealer or import Indi shop, or am I thinking crazy? I know this is a long winded post,but hopefully it will help someone else who runs into this.

 

Ring the dealership & ask how much for a compression test on a rotary.