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Discussion Starter #1
Hello from Australia!

I have been doing a lot of work on my Eunos 800m (2.3 milly) lately and cant seem to clear my codes.

No matter what I do I keep getting codes 11 12 14 & 15. Our cars dont use OBD2 se we use the good old test light and jumper wire on the diagnostic plug to reard out codes.

I previously had more codes but have since fixed them after changing the supercharger and fixing a few cracked and stuffed vac line and T pieces.
Anyways..... im still stuck on my original codes that I had when I first bought the car. cant get rid of them or even clear them. not too sure whats going on.

11 Intake air temp sensor: tested the sensor and its out of spec will get a new one shortly.

12 TPS fixed at 20% open: I believe I have fixed this (I still had continuity when the throttle was opened slightly) now at close it has continuity and no continuity when just lifted like .5mm from the throttle stop. exactly how is should be as stated in the FSM. but this code wont bloody clear

I know its fixed as the throttle response is a millions times better than before, MUCH less throttle input required to get the revs up. Aslo back probed the TPS and was well within spec as per the FSM. No idea why this wont clear

14 Barometric sensor: shouldn't really affect economy or performance that greatly in the real world at close to sea level. It should default to normal atmospheric pressure so no too worried about this one. The sensor is inside the ECU anyways. happy to leave this one be.

15: o2 sensor feedback cancelled. My car only has 2 3wire o2 sensors. not the 2 4wire and 2 3 wire like other models. Anyways replaced them both with universal PEC 3 wire 02 sensors. this should have fixed the code but nope this one wont clear either. sensors tested within spec. In the FSM is says to clear the codes (using the SST some mazda electrical code reading unit), start the engine then run at 1500-2000 rpm for at least 3 mins to reactivate the 02 feedback. I reset the codes (I think, see below) and ran the car within the rpm range for about 5 mins. No good , tried it while running on the highyway a couple of times but still the code remains.

Reseting codes: the code reader guide says to disconnect the neg battery terminal and hold the brakes on for at least 10 secs. I have had no luck doing this... I have left the battery completely disconnected with a 2x4 pushing the brakes nearly all day. no matter what I do these remaining codes will not reset and I cannot get the 02 sensor going again.


I have tried a spare ecu and got the exact same codes.
Anyone know whats going on here, why cant I reset my codes and y cant I get the 02 sensor going again.

the only thing i havent tested is continuity between the sensors signal wire and the ECU pin. This is a huge PITA. its hard enough getting the plugs in and out of the ecu let along back probing specific pins to test them.
i highly doubt there is a wiring issue anyways. everything else on the car is working perfect.

Any ideas would be greatly appreciated
 

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Discussion Starter #2
re adjusted to the TPS last night with a feeler guage as per the FSM
- closed thottle has continuity between terminal c& d
- open 0.19mm still has continuity between terminal c& d
- open 0.37mm no continuity between terminal c& d
output voltage is also within spec.
but code remains.....

this is really doing my head in now
 

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Anyone have any ideas?


Im thinking these are like hard codes that only reset via the code scanner?

Should be getting the new air temp sensor in the next couple days. Will update with progress on that issue.
 

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The entire knowledge base on this forum is built around cars with OBDII.

So it's going to be really hard for anyone here to help with those codes. If your codes were OBDII codes, a simple search of this forum would yield tons of results and how-to guides for it, pictures, instructions and everything you need to fix it. Unfortunately, those codes you have might as well be Greek for anyone here.

I think you would almost have to go to a Mazda Dealership, and have them hook up the NGS (Next Generation Star) computer to your Diagnostic Port, and run a diagnostic on it. Maybe for a small fee than can run the test and give you some kind of printout of the codes, then upload that report here.

Not sure what else to do....
 

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Discussion Starter #9
pretty sure there are no vac leaks, as i just went through it all.
what solenoids would cause these codes? surely if i have solenoid troubles id get more specific solenoid codes.

there are no solenoids to do with the O2 sensor, TPS or Intake temp sensors.

Thanks for the heads up on that other forum, iv registered and posted there too.
 

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pretty sure there are no vac leaks, as i just went through it all.
what solenoids would cause these codes? surely if i have solenoid troubles id get more specific solenoid codes.

there are no solenoids to do with the O2 sensor, TPS or Intake temp sensors.

Thanks for the heads up on that other forum, iv registered and posted there too.
you need to send a private post to grim reaper. and, although there are no solenoids that deal directly with the o2, indirectly they do. if there are leaks in the vacuum system, or bad solenoids, it can cause lean running, and that would trigger the code. i agree with mazda-fla. there are so many problems with the vacuum system, and codes stored become confusing. it is always good to post symptoms with codes, but in this case, not knowing what the comparable obd2 code is, no one in the usa can help
 

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Thanks i have PMd grim reaper. Need to give him my VIN so he can search it up.

Apart from the codes i have have ZERO issues or symtoms. Idle is a touch low since reseting the ecu the last time. I adjusted using the idle air screw and was fine. but it must have ignored my adjustment since the reset. ill close it off completly before i rest the ecu again, reset ecu, get up to temp and adjust idle via idle air screw again.
The car makes great power, has decent economy (very good on highway), not the best with alot of short drives. drives pretty good with great repsonce and smooth delivery.
I just want to get rid of these codes and get the 02 sensor going again. this should give me even better economy.

The only thing wrong with this car is abit of smoke on start up. causing it to use abit of oil. Ill switch to a slightly thicker grade oil next oil change and see how it responds.
 

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OK i have figured out a few things over the last couple of weeks!

My idle kept going low again a few days after adjustment as the o ring inside the idle screw was toast! it was sucking and/or vibrating the screw back to the closed position with each drive!
New o-ring, idle adjusted again, perfect!

Another thing. I noticed my CAC vavle was not operating like it should.
I went through the vac diagram and check every single vac line and tested every solenoid.
- the PRC solenoid was hooked up the wrong way, now fixed. either i stuffed it up when doing the supercharger swap or the previous owners mechanic stuffed it and i copied. I dont think this is a drastic thing from the way is works anyways.
- CAC bypass solenoid was dead.
everything else was fine besides that.
I replaced the solenoid with a similar part from a mazda 626 from pick n payless. CAC now working perfect and guess what????
NO MORE FAULT CODES!!!!!!!!! and running better than ever!!!

Sooooo the TPS, IAT, O2 and Barometric sensors are all fine just like i suspected. Funnily enough the CAC has nothing to do with these stupid codes.
Actually not funny at all when i think about how much time i wasted testing sensors that were perfectly fine.
It must be a only mazda knows combination of xx & xx & xx etc codes means yyy is not functioning.
Luckily you guys mostly have OBD11 as OBD1 is a PITA!!!!! absolutely no support!!!!!!!!

I am happy i finally worked it out and have no codes anymore, but burning i didnt spot it earlier! The CAC valve was staring at me the whole time...

I am still chasing a stumble when the engine is warming up, it seems to be abit better since running alot of injector cleaner but still not sure what it is.
I am going to swap in new coils and get the injectors prefessionally cleaned and flow tested over the next couple months.
 
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