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K. Wiggins
K. Wiggins, ASE Certified Technician
Category: Car
Satisfied Customers: 2880
Experience:  ASE Certified Technician, Associates Degree in Automotive Technology, 15+ years in the trade
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Mazda rx9: I purchased an 06 Mazda rx8 with 103k miles. I took

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I purchased an 06 Mazda rx8 with 103k miles. I took it to the dealer today to put it on diagnostic. I drove it 30 miles with no problems, when I got off the exit and came to a stop, the car wouldn't accelerate over 25 miles an hour. I stopped at auto zone put 2 bottles of heat in gas tank and let it sit for 2 hours. Drove to dealer with no problems. The dealer put it on diagnostics and said the engine the engine had low compression and needed to be replaced along with new plugs wires and coil packs. I picked it up and drove it another 20 miles with only one stumble off a light. Is this dealer blowing smoke? It seems more like wires and plugs to me. It doesn't look like they have been changed recently. Could this guy be trying to screw me for a new engine. In my garage it idles good but when I take it to steady 2000 rpm I can feel and hear a little stumble, and maybe misfire
Did the dealer happen to mention if any trouble codes were present and what they were? Also is there anything on the work order about what the compression numbers were?
Customer: replied 4 years ago.

He never gave me the compression numbers. There were various codes about evap and stuff like that, but the ones that jumped out were just a couple of misfires on #1 and #2. As I thought about it last night when I looked over the engine real close after coming home from the dealer it didnt look like any of the plug boots had even been touched. I'm suspecting the wires may be close to original and from what I could see of the plugs were a little rusty so I dont think those have been changed recently either. The car starts normally and restarts fine when hot. Idles normal but at a 2000 rpm steady pedal in garage, I can hear and feel a little stumble. Thats why I suspect wires plugs or coil pack, but this dealer is trying to sell me an engine change?

If it's idling well the compression is likely OK. There are a few things I would suggest doing. You can go to most parts stores and borrow a compression tester and fuel pressure tester through their loan a tool program by making a small refundable deposit. I would double check the compression then check fuel pressure. If you can drive the car to the parts store and have them pull the trouble codes and post them here that would help too.
That information is whats needed to get a good starting point. From what you describe it sounds more like an ignition, fuel or possible problem with a clogged catalytic converter. If you decide to do the test just pick up the testers and I would be happy to help you with doing them.
K. Wiggins and 2 other Car Specialists are ready to help you
Customer: replied 4 years ago.

The dealer never gave me a list of the codes he saw but on the way home I stopped at Autozone and had the m give me a readout. Here goes. Po302,p2405,po335,po446,po301,p2404.

Thank you that is very helpful information. The PO302, 301 and 335 are all related. The PO335 refers to a problem with the eccentric shaft position sensor. This will cause misfires as well as the problems you were experiencing with it not wanting to run over so many RPM's.
The P2405, PO446 and P2404 all have to do with the EVAP system. This is what vents fuel vapor to the atmosphere and to the engine. A sticking purge solenoid can cause misfires as well as vacuum leaks that will effect engine performance.
In a nutshell, It's pretty likely you do NOT need a new engine. I would still suggest running a compression test but the codes you have are indicative of other less expensive repairs that should resolve this issue. You may want to try a different dealer or an independent shop that feels comfortable and has experience working with rotary engines.
Customer: replied 4 years ago.

I purchased a set of NGK plugs, NGK wires, and 4 new coil packs that I will.install tomorrow. I will.also check and clean eccentric shaft sensor. Is there anything I should do? Another post mentioned a 20 brake pedal pump reset. Not sure what that is. Also an ecc reset??? If we are successful at fixing this together, I will definitely tip you. You have been very helpful and your quick response time has been great! Thx

I'm not sure what they are referring to about a brake pumping reset procedure. The only way to clear codes is with a scanner. You can disconnect the negative battery terminal for 15 minutes to reset the relearn procedure on the computer.
I would honestly recommend doing that compression check before purchasing parts. To properly test the eccentric shaft sensor a lab scope would need to be used. It's possible its getting hot and causing intermittent output issues.
Customer: replied 4 years ago.

when I got back from work tonight i tried to start the car and she wont start. Now the belts are spinning with a whining sound but it doesn`t sound like the engine is even turning over. I tried jumping it with the same result. Belts turning but engine not actually cranking. the battery has 12 volts. could my starter have crapped out? would I still be seeing pulleys and belts turning if the starter crapped out?

IF the belts and pulleys are turning the starter is functioning properly. You need to go by a parts store and pick up a spark tester like this one remove one of the spark plug wires from a plug and hook it to the tester. With the tester adjusted to 30,000 volts clip it to a good ground on the engine and have a helper crank it over. You should see a nice blue spark jump the gap on the tester. If there is no spark it is most likely the eccentric position sensor that has failed. If there is spark you will need to perform a compression test.
Customer: replied 4 years ago.

I was going to stay home from work tomorrow and replace the plugs and wires and coil packs if needed, but it would be a waste if the starter is gone as I wouldnt be able to purchase starter or eccentric position sensor on sunday. This car is driving me nuts! The battery reads 12.1 volts . Let me know if this makes any sense. It sounds like a normal car with starter solenoid spinning, only not nearly as fast, and the belts and pulleys are turning?? Thanks for your patience.

You might want to take the battery to a chain store and have them charge and load test it. A fully charged battery should read 12.6 volts. I'd hold off on plugs and coils. Get the battery checked and we can go from there. I'm glad to assist you with this. I receive notifications of your replies and will respond ASAP when I am available.
Customer: replied 4 years ago.

Thanks. Wouldn`t it have been charged up when I was giving it a jump with my tahoe? I let charge for 5 minutes or so and absolutely no change in cranking.

That should of provided sufficient charge, however if the battery has a weak cell it still may have caused the starter to turn slowly.
Customer: replied 4 years ago.

took the battery to autozone for load test. it passed and they gave it a top charge. Tomorrow i will begin work on it. i will remove and clean eccentric shaft sensor, if that doesnt work, remove plugs and motor with fuel pump fuse removed. i will also try your oil squirt in plug holes idea. if it still doesnt crank, I will replace starter. I cant troubleshoot this thing if I cant start it. Hopefully you will be available tomorrow If I have any questions or run into something new.

I'll be around until 3-8pm est.
Customer: replied 4 years ago.


Customer: replied 4 years ago.

Now that we know the battery is good, do you still think the starter is good since all belts are turning? If so, would removing plugs and cleaning eccentric sensor get her cranking again?

If the starter is dragging it may not be turning fast enough. There really is no cleaning the sensor. you need to test for spark with a spark tester. To properly test the sensor it would need to be tested via lab scope.
Customer: replied 4 years ago.

Today I replaced the plugs with NGK's, 4 coil packs, and new set of NGK wires. The old wires were original from 06, the car had 4 trailing plugs in it that hadnt been out in awhile so I know the dealer couldnt have done a compression check on it. I put it all together and tried it. Same whirring sound. I must have really had it flooded from before, I removed all 4 plugs and they smelled like fuel I sprayed a little choke cleaner on them to dry and for the last 1 hour or so I`ve been cranking for 8 seconds at a time with all plugs out and fuel relay out. then I clean the spark plug hole with a paper towel on a long piece of metal rod I made up. The cranking is getting alot stronger, but I don`t want to try it with the plugs in until I can crank it and the plug hole is dry. am I on the right track? If I can get it started, I think it will run fine. Please advise.

If the plugs are soaked in fuel it most likely not firing. I would advise checking for spark at the plugs with a spark tester as previously mentioned.
Customer: replied 4 years ago.

I checked the spark and they are sparking. The last couple of times I tried to start it. heard a felt a little rumble like it almost wanted to start. I removed the plugs again and they are dry. I have the fuel relay back in, but i turn the key on , wait 5 seconds put gas pedal to the floor and try it. It`s the most hope I`ve had all day. I heard a little burble twice. the starter is definitely working. I`m give it a rest after every 2 tries. I`m afraid to try it with relay in and foot off of gas pedal. I have battery charger on it and it seems to be stronger after waiting a few 10 15 seconds with charger attached. It`s the original battery. I wonder if it has enough cranking amps? I had it tested they said it was good, would the battery charger connected make up the rest?

The battery charger, depending on amperage will compensate some for a weak battery. Is it still turning over slowly?
Customer: replied 4 years ago.
I finally had gotten her where there was no more fuel at the spark plug hole after cranking with plugs out. I must have done it 25 times. I finally tried to start it with plugs in and fuel relay also without keeping my gas pedal floored. She finally started up and I kept her at 3000 rpm for a couple of minutes. Let off the pedal and she idled fine. Took her for a test drive and she ran great. Smooth acceleration, plenty of power. Even the check engine light that had been on forever according to the previous owner was gone. I'm having a hard time believing this engine has low compression like the dealer said. I will drive her tomorrow and decide whether I should still take her for an actual compression test by an indi import repair shop. Thank you for all of your assistance. I really appreciate it!!
Sounds like you might have it taken care of. Yeah, if it's running that good it's definitely not a low compression issue. Let me know if I can assist you further and congrats!