well i posted the same question a few weeks ago and got no help so here's another shot. as soon as the car swithes into open loop under wot the af goes straight lean, and if i stay there for a second longer you can hear it detonating, or ping...which ever the two is caused by lean combustion? but no one could come up with any ideas and the only things i could could think of would be fuel related i.e. failing fuel pump or injectors, since it only happens under wot when the engine wants more fuel? just put new plugs in so thats not it. i dont think it is sparkrelated but anything is possible. i havent seen redline for 6+ months now and im startin to go thru a little withdrawl. if anyone could point me in the right direction i would appreciate it. only mods are cold air, gutted cats, type s, mazdaspeed axelback. is there anyway i can hook up a a guage to read read fuel pressure at its peak flow, and what should that be at wot if anyone might know?(pissed)
still running lean in open loop......
- Thread starter mzdfc3s
- Start date
mzdfc3s said:
Your problem lies with the damn ECU. It is way too smart and wants to stay stoich (14.7 A/F) the only way I got rid of the problem was to install an O2 Modifier. This is wired into the ECU so that tuning is possible via a secondary engine management (ie emanage) I blew my motor so I have a O2 modifier for sale >> http://www.msprotege.com/forum/showthread.php?t=123637441
Check out my FS thread. The price is negotiable. This is my two cents. I had a MS protege running 245-255whp @ 13psi with all stock internals and turbo. But I blew the motor and decided to go back to stock.
yeah thats what puzzles me, there is no cell with this. so that leads me to believe the problem is with the fuel, but i dont know what to look into, im not gonna go out and replace the whole fuel system till i figure out what it is??? spraying out the maf with carb cleaner wont short out the element???
lets say the problem is that it is just not switching from closed loop to open loop. what would cause this.....if the front bank o2 sensor was bad and the rear was still good than it would read the lean condition in open loop. that probably wouldnt be right either, cause then it would throw a cel....where are the guru's 
DSMConvert
AWD...say Bye Bye
- :
- Titanium MS6
well if you're not throwing a code and you truely are detonating, then id lean(no pun intended) towards the first o2 sensor Your ecu uses this sensor heavily to make fuel trim adjustments...so if its getting an incorrect value from this sensor it thinks that everything is fine and doesnt adjust fuel. if it was a fuel pump going or a clogged injector your sensor would pick this up and throw a cell. the MSPs are notorious for going through o2 sensors...
I am making the following assumptions also:
*You have the a/f gauge hooked up correctly to the 1st sensor
*You do not have an fcd or its equivalent hooked up
*You do not have any vacuum leaks associated with the fpr
*You do not have any boost leaks
I am making the following assumptions also:
*You have the a/f gauge hooked up correctly to the 1st sensor
*You do not have an fcd or its equivalent hooked up
*You do not have any vacuum leaks associated with the fpr
*You do not have any boost leaks
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no, this can be at any rpm as long as there is a load and i am approaching wot, right when it should switch from closed to open loop. wonder where i could find a replacement, or better yet...i have a bosch 02 sensor that i never put in my rx-7 and i'm curious if its the same, just a thought since there are some things that are interchangeable.....
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how great is great, i seem to remember oem sensors going for $260 or so.... :-\
i just thought of this though, since i have the mil eliminator installed on the second o2 sensor, it wouldnt pick up any malfunctions coming from the first one...would it? i had to put that on when i gutted the cats.
i just thought of this though, since i have the mil eliminator installed on the second o2 sensor, it wouldnt pick up any malfunctions coming from the first one...would it? i had to put that on when i gutted the cats.
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DSMConvert
AWD...say Bye Bye
- :
- Titanium MS6
your second o2 is essentially no existent as far as the engine is concerned...its only purpose in life is the monitor emissions...so just forget the sensor even exists for the time being....what i would do is pull out your first o2 sensor and spray the hell out of it with brake parts cleaner...more than likely you're going to have a ton of black fluid come back out from all the carbon...80% of the time this makes a big difference in driveability and fuel readings...secondly whenever you swtich from open to close and vice versa you're going to have a few seconds that your sensor will read lean, this is normal and due to the change in the fuel trim..
ill try and pull it and clean it out today, i dont figure there is anyway to test it to see if its completely burned out...? as far as leaning for a few seconds i could see that, but this is def staying lean....
...pulled the b**** out and it really didnt look that bad at all, but i sprayed it down anyway and put it back in. same result, i dont know where to go from here....i cannot understand what is wrong:wtf:
...pulled the b**** out and it really didnt look that bad at all, but i sprayed it down anyway and put it back in. same result, i dont know where to go from here....i cannot understand what is wrong:wtf:
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SoSpicy said:
you have a vac leak, check ALL your connections. then maybe pull your egr and clean it real good too. i had your problem a while back, but i cant remember how i got rid of it....i seem to think it had to be a vac problem though.
and as for my problem.......ITS STILL LEAN.....maybe its not the fuel, maybe the coils are going? anyway to check there functionallity?
mzdfc3s said:
Take the darn MAF sensor out and inspect it with a flashlight. If the little fillament way in there is dirty, clean it!!!!! It will not short it out if you unplug it and remove it. I do it all the time to customers cars and it works. Also, something i discovered the other day on my own msp (with p0171 sys too lean), my upstream o2 sensor looks like its melting its own surronding cage!! Inspect that as well, they always look dirty though.
- :
- Mazda Protege Titanium 03.5
Why would your car run lean if there was no coil to provide the current for a spark plug to ignite the air/gas mixture? My first guess is that your gauge is wrong. my second guess would be between a vac leak and dirty maf.
ZenProtege said:
...well then, you come by and fix it, i'm not makin this s*** up??? i'll buy ya a case of beer if you can figure it out...
as far as a vac leak VA03, which one might you be referring too? a split line could be a possibility, i havent heard anything and def looked over and over.
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