Happily driving at 65mph home one-day when all of sudden the engine loses a good proportion of its power - not all though. i could keep my foot down and still keep it at 65mph. soon after though i got off the highway and managed to get it off into a gas station (final stages requiring a push as the car would not accelerate). fortunately one of the guys that helped push me off the road was a mechanic. we tested all the ignition cables and coils for sparks - determined we had one coil that was bad (connected to the trailing rear rotor (the one closest to the rear of the car).

i changed this coil out myself but still no luck. the car starts but soon quits after ideling for a few seconds. engine sounds weak even for these few seconds.

do i need to reset any of the on-board computer?? (i vaguely remember reading something saying you did have to-i havent done this yet).

also could the engine be flooded? i havent attempted a de-flood yet.

i have just plugged a scanner in and got 9 codes:
P0301 cylinder 1 misfire
MAF circuit high input
P0171 system too lean bank 1
P0113 IAT sensor 1 high input
P0102 MAF too low
P2004 intake manifold runner stuck open control bank 1.

anyone any suggestions?

 

Wow. That's a lot of codes!
Inspect/clean the MAF/IAT unit.
Search for MAF cleaning DIY

P2004 - your APV is stuck open
This would explain some of the other weird readings.

Jon316G is pretty good at this stuff
See this thread, watch the video
https://www.rx8club.com/showthread.p...&highlight=APV

De-carboning using seafoam cleaner may help. Search for the DIY

 

i just cleaned the MAF Sensor still no luck. in fact now it will not even turn over. the battery may be running low though given the number start attempts...

i am presuming not all the codes are actual errors. they are knock-on effects of one problem. at least that is what i am hoping.

does anyone know of anyway you can check the pin contacts to the MAF sensor?

another point, taking out the MAF sensor i noticed a build up of oil in corrugations of the inside of the air intake. any ideas what this could be from?

 

I have a problem with my 8 every time I shift to thrid gear and drive it pass 4500 rpms the check engine starts to flash and then it goes off.. any suggestion on what it may be???

 

tuck, clean out that oil and check your air filter. to prevent this get an oil catch can, search the diy section

rob, when was the last time your coils, plugs, wires were changed? could be a misfire, not good to let this go.

hope this helps but im sure someone much smarter than me will chime in
jesse

 

From what I 've read flooding only occurs during short stops and starts not highway cruising. plus your running lean codes wouldn't a flood be indicated with a running rich code (assuming you got one of course)..

I'd check your coils and plugs it would seem that maybe that is really failing now which is causing your computer to adjust everything else to get a good burn.

I'm curious as to how this ends up. Hopefully you dont have to get a new engine. Keep us posted.

 

200.mph, thanks for the tips, but i just got my engine replaced about two months ago.. and about one month ago i changed the coils the plugs and the wires. i was also told that that coils might be grouding to the plate that is supporting the coils dont know if that might be the problem.

 

It could be. Electricity always wants to find the shortest path to ground and like air it takes the path of least resistance when doing so.

You could be robbing the plugs of the full power the coils provide making them give a weak spark and incomplete burn.

 

I also have a misfire type of problem , mainly noticeable when i accelerate it will splutter before accelerating , and at a standstill when the car is idling the revs go between 1000-3000 revs or stalling its becoming pretty deadly,,engine management light only comes on when it likes but the diagnostic code is p0301 cylinder 1 misfire ,,,,anybody any ideas ?

 

What have you done in regards to the stuck SSV?
This is a motor driven valve at the bottom of the LIM
Sensors tell the ECU if the valve operates.
I recall a TSB for an SSV sensor error for early 2004 models
The self test is performed when you shut off the ignition.

 

An update from me:
i cleaned the MAF sesnor inside and out but still wouldnt start. engine cranks but no ignition.
i rescanned the error codes just for fun and find now that i only have 1 instead of the 9 i began with:

P2004, which is the APV stuck open.

how can i test this myself or should i resign and call out mazda and spend the cash...?

 

I gave you a link to Jon's video for valve troubleshooting.
The APV cycles when ever the ignition is switched off so you can listen for that.
You could replace the motor yourself if it seems defective, you can check the SSV TSB if you have an 04 to see if you qualify or you can try to free up the valve with Jon's method and seafoam down the aux intake runner

 

BAD NEWS TODAY. i ended up taking it to an independant mazda shop. they performed a compression test to find out that 1 rotor was completely dead, the other with minimal life. the apex seals completely dead.
can anyone explain this problem. i mean this happended as i was driving and completely out of the blue. i am lead to believe apex fails when you leave the car inactive for months...

my situation is now do i replace the engine or ditch the car...? Can anyone give me a feel for the kind of price i am looking at? i will find out tomorrow what the shop are offering.

Thanks,
Tom

 

Do you have the compression scores?

From the wording of your post, it sounds like you are saying that you were told scores of 'zero' for the one rotor. If so, this means that they did the test wrong.

OEM spec dictates 6.9 or higher, and I have driven on an engine that tested at 4.8, and it was garbage, but it ran. You can even run a rotary WITHOUT APEX SEALS. It requires like constant 7k RPM or higher in order to get the compression needed, but YES, it will still have some registered compression.

And "apex seal fails when you leave the car inactive for months" is flat out wrong. There are tons of 8s on the boards that go into storage and sit inactive for months on end...namely the winter months.

Honestly, your first post REALLY strikes me as cat getting clogged up, badly.


Care to post who this "independant Mazda shop" is? There are reputable ones, but not very many... and it sounds like you are getting some bad information from them. Perhaps they even used an analog piston compression tester, which won't give you what you need.

 

Please give us some more info...Year,A/T or M/T , How many miles? What service and parts has the car had? Have you been having any other problems. What mods have you got?...How long have you had it? Did you know Mazda gave us a 8yr 100K mile warranty...

 

Thanks for the quick responses.

i am not sure what type of compression tester they had. they were able to read compression from each side of the rotor. rotor 1 spiked at around 4 (not sure what units), rotor 2 was completely flat lined. in an attempt to "relube the seals" they injected oil into the engine to try to increase the compression but they had no luck.

clogged cat could be another problem - i can't say that they looked into this. they focused on the engine first and foremost.

its a 2005, MT, 77000 miles, base model. spark plugs appeared to be originals (or at least old ones). i am the third owner. i cannot acount for all maintence or work that has been carried out by previous owners. i have had it about a yr now and changed oil every 3k miles- thats about it.

i did not know about the warranty to 8yr/100k - i have heard this only applies if you are the original owner. please tell me more.

should i get a second opinion at an official mazda shop....?

Thanks,
Tom

 

Are you in the US? Or elsewhere?

The 8yr 100,000 mile engine core (and engine core only) warranty is available in the US as a factory warranty, meaning it travels with the car. Typically, a replacement engine under this warranty still has additional charges for items that are not the engine core but need to be replaced at the time of the engine change.

Having one rotor "completely flat line" still sounds suspiciously like a test done wrong to me, but at least it sounds like they are using the correct tester.

You very well may have severe engine failure on your hands at this point, but make sure you get that CAT checked out. Your original post states:
"Happily driving at 65mph home one-day when all of sudden the engine loses a good proportion of its power - not all though. i could keep my foot down and still keep it at 65mph."
and
"determined we had one coil that was bad "

are very common with cat failure.

With the information I have from this thread at the moment, this is what I suspect:

1 - Coil and/or plug failure. You state you don't know the history, and you know at least 1 coil was failed.
2 - CAT failure, namely clogged, from the excess fuel from the failed ignition. Clogged cats cause severe drops in power, and end up requiring a pedal to the floor to maintain highway speed. Typically also have a glowing cat under the car, possibly some smoke and other signs.
3 - Continuing to drive like this was severely overheating your engine block from the localized heat buildup, as well as severely overstressing the seals from trying to push out exhaust that wouldn't go. Seals were likely damaged as a result
4 - Your front O2 sensor, and possibly rear, has also been completely fried from the severe heat, resulting in the inability to correctly measure the AFRs.



I could be wrong, if you fill in any gaps that changes this.

 

hey thanks very much. i am in the US and so very relieved to hear the extended warranty on the engine.

it is now on a tow truck to mazda- should i give them a copy of the compression test i had done at the independant shop? or will they not like the fact someone else has done some work on the engine...?
also how much history will they want. i have all the history since i have had the car (9 months) - oil/tires and brake changes. but will i need to track down previous owners?

thanks again

 

From what I have read, you should be fine. I'm sure they will do compression themselves to insure they have proper data to send in.

 

Nah you can't be held responsible for the previous owner. I wouldn't mention the compression test, or any other work done elsewhere, don't give them a reason to give you crap. If they give you any crap ask for test results that they did. many times they say they tested the coils, did a compression test, etc. but then when you ask for results they do not have them. Mazda will require compression numbers before they auth a replacement.

 

Question RIWWP. Would the restricted cat put increased pressure on the rotors to expell the exhaust causing damage to the seals? I imagine if it was a 100% blocked cat the engine would have just exploded when the gases had no were to go and the pressure and temperature increased.

 

"engine exploded", not quite. But significantly increased stress on the seals, yes. Something has to give at some point, and usually it's still a small leak through the cat, possibly through some of the exhaust seals pre-cat, entirely possible some back out the intake, etc... but damage to the seals is entirely possible in a severely clogged cat situation.

 

Okay, perhaps I should rephrase explode I dont mean like in a fireball LOL, but more along the lines of something the weakest point will give in a fantastic release of pressure first...

Good know that maybe his bad seals are a result from his clogged cat and not necessary just the engine alone.

 

UPDATE: Mazda have authorized an engine change under the warranty for 'engine core'. so far they have changed the battery and replaced all the ignition coils.

Should i make a point of inspecting the cat before they fire up with the new engine...?

 

I would and this isn't even from a rotary engine alone standpoint... I had a good friend who blew his motor when he ran a Nitrous set-up (w/o a tune) he had to pay for the replacement obviously but they didn't replace the cat...got a few miles down the road before he blew the second one.