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Discussion Starter #1
Hi everyone, i'm David from Croatia.

I own 1992 Audi 100 (C4) 2.5 TDI ABP...

Was wondering if someone could help me with my problem that i will post on general diesel question...

cheers
 

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Discussion Starter #2
Audi ABP strange pedal problem

Hi,

I have a problem with my Audi.

1992 audi 100 2.5 tdi with a ABP engine.
When driving and you fully release the throttle and next time throttle is applied there is no response. Hit the clutch, engine drops to idle and then away you go again till the next time throttle is released, it doesnt happen on gear changes or when stationary and if you go straight back on to throttle seems ok.it seems as if when coasting injection is stopped but does not restart when going back to drive again unless left to go back to idle. advice would be really nice and greatly appreciated
 

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I have merged your posts so that it's easier to find your posts.

The 1992 was way before North America got any TDI so the engine management may have been a little different. However, the basic troubleshooting should be the same.

This might be a bad accelerator pedal. The fact that the engine goes to idle might be a clue or maybe related to the brake. If you press the brake , the engine should drop to idle. Maybe the brake switch is bad and car thinks the brake pedal is being pressed? If the pedal was bad I would think the problem should be more constant.

Check for any error codes as a first step.
 

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Discussion Starter #6
I have 2.5 TDI C3, year 90' that has drive by wire... it has some differences on the engine head and has 88Kw, not 85...
Some drunk woman crashed into me last Christmas...


:( poor, poor Audi :(
 

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It should not. Since that car was pre-obd2, I'm not even sure how to get the error codes off it. Is there a way to get the check engine light to blink codes or another way to retrieve any error codes?
 

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Discussion Starter #10
I have merged your posts so that it's easier to find your posts.

The 1992 was way before North America got any TDI so the engine management may have been a little different. However, the basic troubleshooting should be the same.

This might be a bad accelerator pedal. The fact that the engine goes to idle might be a clue or maybe related to the brake. If you press the brake , the engine should drop to idle. Maybe the brake switch is bad and car thinks the brake pedal is being pressed? If the pedal was bad I would think the problem should be more constant.

Check for any error codes as a first step.
i tried that, hit the brake but i can rev it up, it doesnt go to idle... and when driving, hit brake a little and its still accelerating... is that broken switch or is that normal for that old car?
 

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Hmmm.....I don't know if it's normal for the older car but on every drive by wire TDI in the US, if you step on the brake while driving, the rpm drops to idle after about 1/2 second.

If you're on the brake pedal, you can rev it up while stepping on the brake first but not stepping on the brake while driving.
 

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Discussion Starter #12
dunno, i can rev it when driving and stepping on the peddal, and my brake light is working while doing that... i dont think that the brake switch is the problem? its strange because it only happens when the car hets warm, on working temperature. MAF? ABS speed sensor? Crankshaft sensor? brake pads running out? dunno... damnit
 

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Discussion Starter #13
any suggestion how to start diagnose with check engine?'... it has something to do with fuel pump relay and puting a fuse in it for few seconds... any clus?
 

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Discussion Starter #14
ok, last weekend there was a huge snow... when driving i noticed that it happens more often regardless if the engine is warm or cold... it happens after breaking... but not every time... i bet its something to do with some ABS sensors, or maybe break light switch?? any suggestions what should i change?
 

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u could have a bad brake switch vw had some recalls!
look in your mirror for brake light to see if switch is sticking.
i had that problem car goes in limp mode.
 

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Discussion Starter #16
I didnt notice that the brake light isnt working. But i had some limp modes sometimes... first things first, brake switch... thx, i'll be with u soon
 

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Discussion Starter #18
i'm bringing this thread up.

I changed crankshaft sensor, TPS, brake switch and something on fuel pump, no difference, anyone got any other suggestions?

fuel pump relay? MAF? any suggestions?
 

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I read your thread again from the beginning, my best guess is something wrong with the injection pump or ECU. I don't know why it would drive fine and then lose power by lifting off the throttle. If it's not air and it's not a compression issue, it's a fuel issue. Something causing the ECU or the pump to restrict fueling.
 

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Discussion Starter #20
compression is very good, its starts very easy, at -5C without any glow plug heating..

i was just goin to check ecu pins... what about any relays?
 
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