Hi,
Have a strange misfire on my 96P 1.6 (AEE) Mk3 Golf.
Only happens at one specific throttle position and only really when under load. If i don't move the throttle when the misfire happens I loose all power and the car just looses speed like it's been turned off... If I open or close the throttle power returns, this leads to some interesting Kangaroo driving in the lower gears ;o)
Power is OK when it's not misfiring.
Fault doesn't seem to happen when the engine is cold, only after running for a few mins. It is very repeatable at the same throttle position when on the hill on my way home from work.
VAG specialist hooked it up to his diagnostics and only faults showing were intermittent throttle position sensor fault and abnormal reading from mass flow (thrust sensor)...
I've checked the throttle position sensor and there doesn't seem to be any issue there, the resistance of if changes linearly with throttle position and it all looks fine. I changed the thrust sensor (2nd hand one) and that hasn't made a difference...
Any suggestions? It's driving me nuts! Can't bear to take it to the VW main dealer and get fleeced...
Off to try a few more things now..
Regards.
Jason
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Do you have an independant diagnostic technician that can hook it up and go and collect live data this may reveal the problem. Regards D
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Jason
You've got the classic symptoms of a throttle position sensor and a code for an intermittant TPS fault. So checking it when the fault isn't apparent won't tell you much.
You need to hook up a meter [or a scanner] and see what's happening when the fault is present - or just go with the code and change it.
The thrust sensor is just VW speak for a MAP sensor with a temp sensor built-in.
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I'm not sure on the throttle positions sensor things, I can't seem to replicate any fault on my multimeter actuating the throttle... and exact position seems to change depending on the load (i.e. less throttle on bigger hills, more on slight hills..)
Just to add to the confusion..... If I disconnect the wire to the purge valve that dumps the fuel vapour into the engine to burn the big misfire seems to go away to be replaced with a lack of power under load, not a massive loss, but noticible.
Guess it might be that valve/solenoid... Anyone else seen that??
Jason
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If you disconnect that then it draws in air all the time the wrong side of the MAP and the engine runs richer to try and compensate and this causes a different throttle position to get the same response. Access to a portable powered scope would help which I am sure you can source and monitor the TPS output this may tell you what is going on. However take a passenger with you to watch the scope. If the TPS is at fault the rading will be wild and the ECU will shut the throttle down thus the loss of power. To monitor slip in a single strand of multi core wire into the connector on the effected pins and carefully reconnect. use 10:1 high Imp probes and trial them through the bonnet and door rubbers to the scope. Regards D
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Jason - I've got identical problems at the moment on a 1.6 AEE. Have you had any luck working out what was wrong?
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Yes he changed the TPS this fixed the prob but tick over was 1500 rpm or so but his VW indi set factory defaults for the ECU and hey presto fixed. JasonD is my son. Regards Peter
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Hi Peter, cheers for the response. Now I've just got to try and find a TPS!
Cheers
Phil
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I've emailed him for the supplier.
Regards Peter
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I believe that they're available from people called Volkswagen dealers....
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www.vwaudibreakers.co.uk/
He purchased a MAP and a TDS for £25.
Regards Peter
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Cheers for the link Peter. Was that a TPS not TDS? Also (and forgive me if I'm being really dense here) what's the MAP?
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Sorry yes a TPS and a Manifold Absolute Pressure sensor. Regards Peter
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