After all of those months and spent money (ALOT)-still misfire.
05-03-2010, 01:49 PM
#1
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After all of those months and spent money (ALOT)-still misfire.
Well, like title said..after all of this time and spent money car still misfires..
have 13.8 compression in all cilinders.
injectors have been cleaned.
wiring harness checked
ISV cleaned
IAT checked
both flywheel sensors replaced
maf changed
lambda with 4 wires
vaccum leaks all checked-nothing.
TPS changed and calibrated.
we tuk engine out and replaced all gaskets.
both detonation sensors replaced.
rotor caps-rotors-wires-and plugs replaced
right on mark timing marks.(have been checked by audi dealer)
distributor changed, passenger side with new hall sensor.
charging voltage 13.9volts
both ignition coils replaced
and lots more..
AND IT STILL MISFIRES, not as bad as before but you can feel it while touching the engine/body or beeing in cab or eaven hear it ..
have been 5 different type shops to read codes and test things..
they say its all okey but they cant seem to find out why its misfiring.
if ENYONE out there have been in this situation with your/somebodys audi v8 4.2 quattro and you have found solution, please reply ..
Regards.
Silver
have 13.8 compression in all cilinders.
injectors have been cleaned.
wiring harness checked
ISV cleaned
IAT checked
both flywheel sensors replaced
maf changed
lambda with 4 wires
vaccum leaks all checked-nothing.
TPS changed and calibrated.
we tuk engine out and replaced all gaskets.
both detonation sensors replaced.
rotor caps-rotors-wires-and plugs replaced
right on mark timing marks.(have been checked by audi dealer)
distributor changed, passenger side with new hall sensor.
charging voltage 13.9volts
both ignition coils replaced
and lots more..
AND IT STILL MISFIRES, not as bad as before but you can feel it while touching the engine/body or beeing in cab or eaven hear it ..
have been 5 different type shops to read codes and test things..
they say its all okey but they cant seem to find out why its misfiring.
if ENYONE out there have been in this situation with your/somebodys audi v8 4.2 quattro and you have found solution, please reply ..
Regards.
Silver
05-03-2010, 03:47 PM
#2
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ok,
this car is back to stock? 4.2 wiring and ecu, 4.2 tps, ect???????????
I had responded to your last missfire thread so I remember a few posts in it.
tell me when the missfiring started.
and under what circumstances.
this car is back to stock? 4.2 wiring and ecu, 4.2 tps, ect???????????
I had responded to your last missfire thread so I remember a few posts in it.
tell me when the missfiring started.
and under what circumstances.
05-03-2010, 10:32 PM
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car is stock 4.2, with all of components are from other 4.2 or are new.
misfire have always been since i bought the car.
have 4.2 wiring (8 different injector pins from wiring to ecu socket)
4.2 ecu deffinetly..
it starts good with -24 c
altho it starts good with any weather.
but misfires from cold to hot ..
Regards.
Silver
misfire have always been since i bought the car.
have 4.2 wiring (8 different injector pins from wiring to ecu socket)
4.2 ecu deffinetly..
it starts good with -24 c
altho it starts good with any weather.
but misfires from cold to hot ..
Regards.
Silver
05-06-2010, 07:18 AM
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05-06-2010, 10:03 PM
#7
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I tok the engine and gave it to audi dealer, thy put timing right.., nd as if i watch camshaft 0-s and distributor lines, its right on mark ..
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05-08-2010, 06:31 PM
#10
AudiWorld Member
what are you implying when you say "misfire". Are you stating it's a plug thats missing, a dead cylinder (ie, stuck valve), an ignition short? Could the rings in one cylinder be lining up reducing compression?
How long after start up is this happening? Is it random or constant?
To rule out the ignition have you tried inline spark testers on the plug wires? Get two of 'em and run the car to see if they blink. Also there is an old school tool called the KV meter that reads the voltage drawn through each plug wire. This is helpful in telling you if there is a large drop between cylinders causing a misfire feel. symptoms can be fuel as well as spark.
When you replaced gaskets did you include head gaskests? Did engine seem to run smoother after reinstallation?
This may be a stretch but have you checked/replaced the instrument cluster? Not an Audi, but I had two instances where the tach was to blame. One was a ford with an aftermarket fuel system and ECU. Tach would burn the components on the board. Other was a toyota/isuzu mutt. their runability issues were spiratic and both vehicles smoothed out once tachs were disconnected.
How long after start up is this happening? Is it random or constant?
To rule out the ignition have you tried inline spark testers on the plug wires? Get two of 'em and run the car to see if they blink. Also there is an old school tool called the KV meter that reads the voltage drawn through each plug wire. This is helpful in telling you if there is a large drop between cylinders causing a misfire feel. symptoms can be fuel as well as spark.
When you replaced gaskets did you include head gaskests? Did engine seem to run smoother after reinstallation?
This may be a stretch but have you checked/replaced the instrument cluster? Not an Audi, but I had two instances where the tach was to blame. One was a ford with an aftermarket fuel system and ECU. Tach would burn the components on the board. Other was a toyota/isuzu mutt. their runability issues were spiratic and both vehicles smoothed out once tachs were disconnected.