Tdi 90 cutting out

Charles said:
I'll report back!
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I’m still hard over on it being the crank sensor

Btw even if the batter is removed the fault codes logged in the ecu will remain until cleared. You can even take the ecu out of the car the fault codes are still there until you clear them with a code reader eg vcds


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depronman said:
I’m still hard over on it being the crank sensor

Btw even if the batter is removed the fault codes logged in the ecu will remain until cleared. You can even take the ecu out of the car the fault codes are still there until you clear them with a code reader eg vcds


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The way the rev counter behaves, when the fault occurs, is the test of crank sensor health.
Mac
 
Just realised, the behaviour of the HVAC points to crankshaft too. If nothing from that sensor, the car thinks the engine is not running, so fan stays on, but defaults to recirc, (a guess, but sounds like it with ignition on, engine off), closing the fresh air>evaporator path, so no cold air.
Mac.
 
PlasticMac said:
Just realised, the behaviour of the HVAC points to crankshaft too. If nothing from that sensor, the car thinks the engine is not running, so fan stays on, but defaults to recirc, (a guess, but sounds like it with ignition on, engine off), closing the fresh air>evaporator path, so no cold air.
Mac.
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Will be interesting to see if the wom lads get to the same conclusion
I’d be swapping out the crank sensor even though it’s a bitch to get too. Mr Audi want a good talking to as they put the oil cooler in the way of crank sensor removal making what should be a 15 job into a 2 hour plus job

Paul


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For future reference, if you set VCDS to log Group 001, while turning the engine over on the starter, Block 01 is Engine Speed, G28 - Crankshaft Sensor.
Mac.
 
PlasticMac said:
Just realised, the behaviour of the HVAC points to crankshaft too. If nothing from that sensor, the car thinks the engine is not running, so fan stays on, but defaults to recirc, (a guess, but sounds like it with ignition on, engine off), closing the fresh air>evaporator path, so no cold air.
Mac.
Click to expand...
So wom changed the cam sensor, it has developed a few faults logged, with intermittent crank sensor, intermittent cam sensor and all 3 glow plugs where borked.
 
That should sort it.

Makes sense as I believe if one sensor is iffy the car will still run using the other - it obviously can’t do that if they’re both playing up occasionally.
 
dj_efk said:
That should sort it.

Makes sense as I believe if one sensor is iffy the car will still run using the other - it obviously can’t do that if they’re both playing up occasionally.
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Car will run without the cam sensor but will take longer to start as it needs several engine revolutions before the ecu works out which cylinder is on the compression stroke and therefore which injector to fire
It will
Not run if the crank sensor fails

Paul


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dj_efk said:
That should sort it.

Makes sense as I believe if one sensor is iffy the car will still run using the other - it obviously can’t do that if they’re both playing up occasionally.
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It won't even start with a duff crankshaft sensor.
I think the dodgy cam sensor will allow it to run, but trigger an EML if consistent
Mac.
depronman said:
Car will run without the cam sensor but will take longer to start as it needs several engine revolutions before the ecu works out which cylinder is on the compression stroke and therefore which injector to fire
It will
Not run if the crank sensor fails

Paul


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If rev counter shows starter is spinning, then it's not the crankshaft sensor. It's a very easy, and unambiguous diagnostic for crankshaft sensor failure, or not..
Mac.
 
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