Crank position sensor

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Topplumb1

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Can anyone throw any light on this :
Car is a 1999 1.8tqs with AJL engine - problem is an intermittent stalling fault which does not happen very often but a real pain when it does, can do over 100 miles with no problems at all, car idles perfectly and pulls in every gear right through the rev range with no loss of power etc in every gear, once into 5th gear and when slowing for a change into 4th, put the clutch down and the rev counter immediately hits zero and the engine stalls, this always happens when the engine is up to temp and for no apparent reason, no codes are showing via vcds , and so far I have changed :
Ignition control module
MAF Sensor
Temp sensor
Lambda Sensor
I am now looking into finding where the Crank Position Sensor and the Cam Sensor are both located (photos would be great) to replace the two items together, also need part numbers if possible.
Thanks guys.
 
Doubt its the cam sensor the engine will happily run with that unplugged.

Crank sensor is on the left side of the engine block down behind the oil filter housing, near the gearbox flange.
 
Thanks Aragorn plan to have a look at the weekend - I'm determined to get to the root of the problem as this has been going on for 18 months !
 
So the weekend came and I replaced the crank sensor ........... car went fine for a few journeys, then same problem again, this time between 3rd and 2nd gears, the rev counter started to dance around then went to stall but I let the clutch up to keep the engine going as it was as I was turning into a corner off a main road, if you don't do that the power steering goes all heavy and you end up mounting the kerb and risk damaging something :rage:!!!!
So what is causing this intermittent problem ?
Replaced so far :
Ignition control module
MAF Sensor
Temp Sensor
Lambda Sensor
Crank Positioner Sensor
Has anyone else ever had a problem like this before with their Audi ? :greyrs4: :notworking:
 
is the ECU reporting any faults?

You've changed a lot of parts, but the parts you've changed, if they really were faulty, would have logged a fault code.

It sounds like a wiring fault, perhaps a loose earth connection or similar. Check all the engine earthing points, including the bundle that bolts to the bulkhead.
 
On Saturday vcds did not pull up any fault codes what so ever, sorry for being thick, but can you explain the abbreviation ECU - is this engine control unit, emission control unit or some other control unit beginning with E !!!
In the past (about a year ago) the occasional fault codes have been :
65535 internal control module memory error 35-10........intermittent ( don't know what control module this means maybe this is my problem)
01366 opened due to crash signal 35-00 ( don't know what this means that has been opened)
 
ECU is electronic control unit, but in this case specifically means the engine.

the two codes you provide are probably from the Airbag system?
 
Thanks I'll investigate further with earthing points and wiring.
 
So another weekend arrives and I did some electrical investigation work on the car, I took off the battery earth lead from the body of the car at the bulkhead and found it was somewhat grubby and dirty, the earth looked like it was only making partial contact with the bulkhead.Did the same with the positive lead and polished them both and they now look as shiny as gold - maybe this will stop the intermittent stalling fault, I will now run the car like this to see if there is any improvement :greyrs4:
 
Tonight I checked the earthing points under the relay carrier - they looked pristinely clean and were tight like they had just come from the factory, also had the top of the electronics box off and the only earth in the bulkhead I could find is the battery earth. Are there any other earth points that can be checked or other electronic components that could be causing this problem?
 
if your standing looking at the enginebay, theres an intermediate firewall that seperates the battery etc from the main engine bay. On the passenger side, the wiring harness for the engine comes thru a big rubber grommet in that firewall and turns down behind the coolant reservoir. Theres also a plastic carrier on the firewall next to this with some electrical plugs on it.

You might need to move the coolant bottle to get at it, but between the plastic carrier and the grommet, is a bolt which takes all the earths from the engine wiring harness.
 
Thanks Aragorn - found said earthing point, and on inspection it was quite grubby and dirty, disconnected it and polished it like gold around the bolt as well as the copper wire connectors, also sprayed with electrical contact cleaner. Will run the car now and see if the problem occurs again......... watch this space !
 
So over the weekend I drove the car for as many journeys as I could and the problem has slightly changed.......................
What happens now when you put the clutch down to change gear, is the rev counter drops to just under 1000 rpm then the idling goes all erratic making the rev counter go up and down, but does not actually stall.it never goes above 1000, I managed to get it to do this by experimenting by dipping the clutch when in 5th gear but not actually changing gear, after about 4 seconds the idling becomes normal, 4 times in succession I did this and every time it happened, then on the next time I did it, was perfect for every time I tried it, it has not done it again since!
 
Thanks Aragorn I'll have to work out where all the vacuum hoses run and check all of them.
 
I had a very similar problem which turned out to be loose earth by the starter motor and the cam shaft sensor was gone , it took about week to bring a code up . When this happened it was sounding noticebly rough and was under powered. But it was on a mk4 golf 1.8 20v practically the same engine...
 
Thanks - its not pulling any fault codes up which makes it so difficult to diagnose, some one suggested throttle position sensors, not sure if the 1.8tqs B5 AJL engine has these though - could be one or two maybe, any info and part numbers welcome as I would like to replace them to eliminate them, and where are they located ?
 
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