i am a rotary newbie and i own a small auto dealership in winter springs FL check us out at www.powerautosales.com anyway i got a turbocharged rx8 at the auction last week. it appears to have the greddy turbo kit on it along with a trust maf sensor and air filter. i knew there was a fuel management problem when i got the car but i need your advice. apparently the person who previously owned the car dumped a ton of money in it and used a unichip plug and play computer instead of the greddy emanage. i dont have any experiance with either one but the car is running extremely rich and stalls out when the car is moving and the clutch is pushed in. I removed the unichip and plugged the factory wires back in to the ecu to see if it would stay running and it did for a little while. when the car warmed up it started bucking and stalling again. i have an actron handheld obd2 scanner and it gives me a link error when i try it on the diagnostic port with the stock ecu. the scanner is a cheapie $150 one from advance auto parts, but i have used it on cars as new as 2005 and it has always worked fine. i have a feeling that the factory ecu is bad. please let me know what you think and if you have run into a similar situation.

 

Make sure it is a Canbus compatible scanner. If it is, check the 15a room fuse, it powers the diagnostic port.

I very much doubt the stock ecu is bad. Sounds like you might have a leak somewhere and metered air is escaping the system. I would check your BOV first. Make sure it is properly tightened, and not leaking. You might even consider switching to a recirculating type.

 

Like ^^ said, you need the *newest* can-bus compatible scanner.

there should be at least a e-manage blue with the kit (newer one comes with e-manage ultimate) do NOT run the car without any engine management on. its going to break something.

Now .... what I suggest is that, you can spend 600 more bucks and buy the emanage ultimate upgrade kit and tune it so you can sell it (that should be the result you want, right ?) if you put a bit more money to this car, you can find a shop and tune it, because stock ECU comes with a VERY VERY VERY VERY rich setup. and I dont think any potenial buyer will like to see the smoke coming out of the exhaust.

Or you can try to tune it yourself. lots of help around the internet.

It might be painful at first but you dont want to start your 8 anymore cuz it might blow your motor.

 

you can run the car without engine management... you just don't want to go into boost

true the stock ecu comes with a rich setup.. if you're running N/A... but it's definitely not "rich" enough for use with the greddy kit.

anyway, to the original poster: I suggest following rkostolni's advice

Personally, i haven't read anything on this board about anyone using a Trust MAF sensor with a UTEC system so it may be a little difficult for anyone but the most experienced guys to help you out with that. It's not that complicated but not a whole lot of people here are going to know the voltage range of that sensor. So let's just hope the problem is not the engine management.

BTW, have you talked to the previous owner about the problem? If the car used to run fine and now it doesn't I doubt it's anything to do with the tune.

 

canbus i thought that was what i used to smoke in high school LOL...
i have the actron cp9135 according to the actron website it will work with any 1996 and newer vehicle. but if you know better please tell me.

my first guess was a boost leak and i have already had it on a lift and had my dad rev it up while i listened and felt around. all of the hoses are good and tight and the bov does not release any air untill it is supposed to.

the weird thing is that it runs fine with the stock ecu alone untill it gets hot. then it bucks above 4k and stalls when the gas i touched lightly or when the car is moving and the clutch is pressed.

does anybody have any experiance with this unichip thingy. i like that i dont have to cut any wires to make it work. does greddy have a harness that does not require cutting and splicing?

if i have to i will take off all of this turbo crap and make it stock and take it to the dealership it only has 18k miles on it and should be under warranty.

 

does anybody have all the parts to make it stock. manifold exhaust stock airbox and maf

 

If the problem is only apparent when the motor is hot, you should probably perform a compression test.

 

what is the compression supposed to be?
which set of sparkplugs are the correct to test from?
is it common to lose compression when the engine is hot?

 

also would a lack of compression cause the excessive rich mixture?

 

You can check the compression through either spark plug hole. Although, usually it is done through the trailing because it is easier to access. The value depends on your cranking speed, check the manual for the exact specs. Rotary compression naturally goes down as the engine temp increases. If there is excessive wear/clearances, the compression can fall too low for proper operation.

 

Does the motor run if you give it gas, or does it eventually stall no matter what? A motor that runs can idle at startup but stalls when warm is a sign of a broken apex seal.

 

that actron scanner is OBDii compatible but not CAN compatible. so its of no use to you with the rx-8 PCM.

 

check the unichip site http://www.unichip.us/ to find a qualified unichip tuner near you. htey should be able to tune it fairly easily. where are you located?

 

He claims the car stalls even without the Unichip plugged in. So I don't think this is a tuning issue.

 

thats why I said do NOT run the car without engine management .....

I guess he should go have a Unichip guy take a look at it. theres something seriously wrong there ... and maybe like evil said .... the apex seal might be going ......

 

tanks for all of your help so far.
i ordered a new scanner to see wtf is going on with the ecu. any opinions about the auterra pc based diagnostic scanner?

I want to run a compression test on monday does anybody have the compression specks?

the engine will idle when it is hot it just bucks above a certain rpm and stalls at lights. when it is restarted it idles but the exhaust is really rich smelling and if it is revved up it puts out a puff of black smoke.

 

rich, and maybe a broken apex seal... the comp test for the rotory is not the same ...

scan tool. hymee scanalizer at mazdaprart.com... or harrison... but have been some problems..

first i would check all rubber connectors...

beers

 

if you ran the engine without any kind of management system I would say you poped a seal. the ecu has no idea what boost is so when you got in it, the computer is still trying to hit the 14.7 that its suposed to which is way too lean for a boosted car. When this car warms up it changes from a closed to an open system the closed is rich, maybe rich enough for the turbo to be "ok" but as soon as it gets warm enough for the open to kick in and it starts trying to hit the 14.7 you start running lean, very very lean, and the puter will see this and will say oh ****. Thats just my 2 cents on it.

 

^ I assume he didn't boost on his stock computer. I would hope he had more sense than that.

Also, the ECU doesn't shoot for 14.7 under heavy load. That's only during cruise or light load.

 

That's EXACTLY what my car did when I broke a seal.

 

what is the spec for the compression

 

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beers