Some of you will have noticed the "3.2 misfire at 2k thread" which has now passed 6 pages and 250 posts . Audi and independents have no answer for this misfire problem and between half a dozen of us we have changed many thousands of £ of componants...from fly wheels to cam chains and VVT gears to remaps...
I am posting this here because i doubt that anyone other than a few of us with the problem read the thread.....so does anyone who knows auto electrics think this makes any sense ??
The thing we have in common is the 2k bit. So what happens on our cars at 2k ??? Well I think that could well be the start of the advance curve. I no nothing about cars but I do know about bike engines. The advance curve would run from about 5 ° before top dead centre ( BTDC) to approx 35° (BTDC)..
We know that at tick over (off the advance curve) things are ok, we know on cold mornings when the engine advances its self to a higher rpm tick over ( above the std 5° BTDC) things are ok. We know that once the advance curve is started we are ok.
So what if the sensor/sender unit that triggers the advance is fluffy and the advance is jumping. Fore instance you could have a point where the plugs are firing at different advance levels each 6 cyl rev. this would in affect throw everything out from your spark to valve timing to injector spray in relation to the pistons position/spark but by maybe only a few degrees
If the advance curve started to early or late the knock sensor might be cutting in and trying to ****** the ignition just as the ECU is trying to advance it .Suppose by 40-50k miles the compression has risen due to coke because the oil fume recycling is throwing oil into the bores
This would not show up on a remap because although the remap basically adjusts the advance curve, remaps start to adjust over 2krpm
The reason we dont get this when we are on Choke could be that the engine is already advanced to a point above the normal 2krpm start of the advance curve.
Now if it was a bike I would simply put a strobe lamp on it and set the tick over at 2krpm and check the timing marks and position with a degree disc .but its a ****** car !!!
TIA
I am posting this here because i doubt that anyone other than a few of us with the problem read the thread.....so does anyone who knows auto electrics think this makes any sense ??
The thing we have in common is the 2k bit. So what happens on our cars at 2k ??? Well I think that could well be the start of the advance curve. I no nothing about cars but I do know about bike engines. The advance curve would run from about 5 ° before top dead centre ( BTDC) to approx 35° (BTDC)..
We know that at tick over (off the advance curve) things are ok, we know on cold mornings when the engine advances its self to a higher rpm tick over ( above the std 5° BTDC) things are ok. We know that once the advance curve is started we are ok.
So what if the sensor/sender unit that triggers the advance is fluffy and the advance is jumping. Fore instance you could have a point where the plugs are firing at different advance levels each 6 cyl rev. this would in affect throw everything out from your spark to valve timing to injector spray in relation to the pistons position/spark but by maybe only a few degrees
If the advance curve started to early or late the knock sensor might be cutting in and trying to ****** the ignition just as the ECU is trying to advance it .Suppose by 40-50k miles the compression has risen due to coke because the oil fume recycling is throwing oil into the bores
This would not show up on a remap because although the remap basically adjusts the advance curve, remaps start to adjust over 2krpm
The reason we dont get this when we are on Choke could be that the engine is already advanced to a point above the normal 2krpm start of the advance curve.
Now if it was a bike I would simply put a strobe lamp on it and set the tick over at 2krpm and check the timing marks and position with a degree disc .but its a ****** car !!!
TIA
