SERIOUSLY hesitating & back firing!

[ad4m1]

injector resistors

[ianelvar]

Doesn\'t the apexi have PWM current limit? Strange...
Anyway, could be a number of things that make it run pig rich - might not be coils, but they\'re worth checking. We\'re looking for an intermittant fault, so more than likely a bad connection somewhere. You don\'t have to take the plenum off to test the coils or have a prod at their connectors. Just remove the intake elbow and you\'ll be fine. The coil connectors are a bit flimsy, so check that the clips are still there and the metal inserts haven\'t come loose.
You could also check the cooland temp sensor, map sensor, and crank angle sensors. Do you get any out of norm readings on the commander while it\'s being funny? Low engine temp, high manifold pressure reading etc?

Just another thought, but could the fuel pressure be doing funny things? From the pics you\'ve got a aftermarket rail, so I\'m assuming you\'ve got some kind of non-original regulator? Might be worth checking before you get too burried in the wiring. A dodgy regulator could easily make it over fuel.

[Dizz]

Doesn\'t the apexi have PWM current limit? Strange...
Anyway, could be a number of things that make it run pig rich - might not be coils, but they\'re worth checking. We\'re looking for an intermittant fault, so more than likely a bad connection somewhere. You don\'t have to take the plenum off to test the coils or have a prod at their connectors. Just remove the intake elbow and you\'ll be fine. The coil connectors are a bit flimsy, so check that the clips are still there and the metal inserts haven\'t come loose.
You could also check the cooland temp sensor, map sensor, and crank angle sensors. Do you get any out of norm readings on the commander while it\'s being funny? Low engine temp, high manifold pressure reading etc?
 
Just another thought, but could the fuel pressure be doing funny things? From the pics you\'ve got a aftermarket rail, so I\'m assuming you\'ve got some kind of non-original regulator? Might be worth checking before you get too burried in the wiring. A dodgy regulator could easily make it over fuel.

From what I remember the fuel pressure regulator looked like a standard one which had me wondering, it just has braded & silicon lines off it. I\'ll try get a look later & few pics of the entire setup. I just find it weird that it was running fine & isn\'t now just all of a sudden.
 
It literally happens as the engine reaches about 86 degrees it starts to idle badly & then miss firing & back firing. All the values on the hand commander stay the same (roughly), no major changes. I will have a go later & just watch it while it\'s starting to happen maybe

[MaLicE]

if you press the up button on the commander it will show peak values...

if you get it displaying 4 values you can press the up button it will show you the current live value and also peak hold value at the same time...

might be worth downloading the powerfc manual as it will tell you how to use the commander also... if you look it the technical guide part of this forum i think there is a link to download it

[MaLicE]

http://www.mazdarotaryclub.com/forums/showthread.php?t=37534

found the link for you

[ianelvar]

Cool. Let us know what you can see from the commander. It\'s only an idea about the regulator, and I\'m not so sure about it if you\'re saying it only happens once you reach a specific temp. Is the reg still connected to the solenoid, and the solenoid to the manifold? Pics would be good to see how its connected.

[Dizz]

Thanks guys, brought it out to the guy who rebuilt the engine today to see if he had any ideas, car ran perfectly the whole way there & while it was there & he was looking over it. The only thing he noticed on the hand commander was the throttle position sensor voltage was out of range (0.3v I think). Then as soon as I was on my way home it started acting up, it\'s getting a lot worse now too :mad: :Grrr
 
Was on the motorway & then came off, came to the first traffic lights & the exhaust note changed, was hard to accelerate as usual (no power/misfire) & then the bangs. Wouldn\'t clear out again until I went back onto the motorway & had it in fifth gear at about 3,000 rpm for a few mins & it "coughed" back to normal exhaust note & reved freely until again I came back off the motorway & slowed down & hey-presto it happened again. So sick of it, can\'t drive the car at all anymore. It just sits in my driveway :mad:
 
@ ianelvar: I took some pics in the engine bay 2day, will try get them up 2mor

[cyman]

this may have nothing to do with ur prob but i though i would post it anyway.
 
i had exactley the same problem as you was fine one minute then a pig the next went through all sorts of checks and found that the water temp sensor seemed to be going all over the place even giving negative figures on the commander i went through all sorts of checks wiring etc then took the power fc ecu out and checked the connections, they were mainly fine but some were green corroded, (the ecu was 12 months old) cleaned up the connections and all was good for a while until out of the blue it did it again. i pulled out the ecu to find some moisture on it.
 
what had happened was there was a v small water leak that was comming in through a screw that held the plastic cover on below the windscreen this leak went into the air blower then slowly dripped out onto the wiring and ran down the commander cable into the ecu, this caused the corrosion and the ecu to go loopy (the last time it played up it had rained the night before) as a temp fix i dried out the ecu sprayed the connections with connection lubricant and put the whole lot into a freezer bag and put it back in place. this was over a year ago and i never had the problem since and although i have resealed all the plastic trim screws my ecu still sits in its nice raincoat.
 
like i said may not be the same as your prob but the symptoms are identicle.
 
good luck sorting your probs out

[Dizz]

Thanks man, just in the middle of checking over a few things so will check that too
 
The engine builder told me to check the ECU wiring alright for loose connections but checked & can\'t see any. I did find hand writing on the back of the ECU though which I can only presume is by Pip saying that there\'s only a mase map on the ecu & that it needs to go on a dyno to run "safely"...
 
I just find it weird that it only seems to be when the engine is hot & never cold. My head\'s melted at this stage becaust I can\'t drive the car so can\'t get up the mileage to go over to Pip for remap :Hammer

[bnaellis]

Thanks man, just in the middle of checking over a few things so will check that too
 
The engine builder told me to check the ECU wiring alright for loose connections but checked & can\'t see any. I did find hand writing on the back of the ECU though which I can only presume is by Pip saying that there\'s only a mase map on the ecu & that it needs to go on a dyno to run "safely"...
 
I just find it weird that it only seems to be when the engine is hot & never cold. My head\'s melted at this stage becaust I can\'t drive the car so can\'t get up the mileage to go over to Pip for remap :Hammer

If the throttle pos sensor is out of range that will cause the problem especially when the engine is warmed up. ajust it so it\'s in range and bob should be your uncle.


rgds
Brian

[Dizz]

I\'ll give it a go now if I can figure it out, cheers mate, I\'ll let you know! Fingers crossed! :driving

[Dizz]

Went to do this earlier on & the figures were almost spot on already so couldn\'t do anything with it :mad: Don\'t know how he thought they were out of tolerance :xconfused

I had it running in my front garden for about 15-20  mins & it was perfect, only seems to be when you drive it & then come to a stop :Grrr

Back to the drawing board ...... :3Confused

[cyman]

Went to do this earlier on & the figures were almost spot on already so couldn\'t do anything with it :mad: Don\'t know how he thought they were out of tolerance :xconfused
 
I had it running in my front garden for about 15-20 mins & it was perfect, only seems to be when you drive it & then come to a stop :Grrr
 
Back to the drawing board ...... :3Confused

dont forget all signals go thrugh the ecu. if u have corrosion on any connections or moisture in the ecu it can give false readings on the commander like it did with mine, or have you checked these already?

[MaLicE]

have you done a sensor check on the commander to make sure they are all working??? it will show up if any sensors are out, i would go about replacing all of them first

[Dizz]

Ye mate, tried that alright. It didn\'t show up anything... :mad::mad:
 
Calling over to AndyGen3 on Sat & going to try his coils on it & maybe a few other things to try get to the bottom of this. Then straight onto WGT to get booked in :chat