Worrying experience...

[Daveperc]

Guess I need a crank sensor! Anyone here know a cheap supplier?

Not sure this is the part to go "cheap" on - it's a pretty vital protection for the engine!

I haven't had time to trawl back through posts but IIRC the wiring to the sensor can get pinched somewhere so it may not be the unit itself. I think however it's a front end off job to change, so I would think in terms of a realy good check on cambelt, and the timing chains and tensioners at the same time unless they have recently been done. And if they were done shortly before the problem started, then I guess I know who trapped the wire!!

My inclination, given that you are in W LOndon, if a pleasant run up to Banbury to get it sorted

Dave

[rossi46]

Sounds good
TPS would be the best place to start

[chrisn6]

Guess I need a crank sensor! Anyone here know a cheap supplier?

Not sure this is the part to go "cheap" on - it's a pretty vital protection for the engine!

I haven't had time to trawl back through posts but IIRC the wiring to the sensor can get pinched somewhere so it may not be the unit itself. I think however it's a front end off job to change, so I would think in terms of a realy good check on cambelt, and the timing chains and tensioners at the same time unless they have recently been done. And if they were done shortly before the problem started, then I guess I know who trapped the wire!!

My inclination, given that you are in W LOndon, if a pleasant run up to Banbury to get it sorted

Dave

Thanks Dave. I guess it is more likely to be a poor connection since the car is running fine again. Still as you say, this is an opportunity to get the covers off and check everything around there. I'm relatively close to Virdee in Park Royal and he has been very good so far, so looks like I'll be dropping off the car to him next week.

~Chris

[Daveperc]

relatively close to Virdee in Park Royal

Yep - great alternative - hope they find the problem for you.

How many miles since last cambelt change?

Dave

[chrisn6]

relatively close to Virdee in Park Royal

Yep - great alternative - hope they find the problem for you.

How many miles since last cambelt change?

Dave

Only about 15K, so not necessary to change it unless it looks dodgy once the covers are off.

~C

[chrisn6]

Thinking out loud now. If the crank sensor or wiring to it is faulty, why does it work perfectly once the engine starts? The car doesn't miss a beat once it's running. The Vag Com clearly indicated a faulty crank sensor, but surely in 5 weeks of driving, the 'fault' would have shown up whilst driving, no? I've used it twice since the non-start yesterday and again it is running perfectly.

~C

[chunky79]

Just wanted to say thank you to all, especially Shop. I ran the VAG COM Lite and it showed "Engine Speed Sensor (G28): no signal/communication - Intermittent". Guess I need a crank sensor! Anyone here know a cheap supplier?

Cheers,

~Chris

^^^^ key word, intermittent^^^^^
Electric faults can be a pain in the knot hole. It could be a bad connection but could also be a bad sensor. Sometimes the only thing to do is change the part.

Very good call by Shopp yet again though!

[chrisn6]

Just wanted to say thank you to all, especially Shop. I ran the VAG COM Lite and it showed "Engine Speed Sensor (G28): no signal/communication - Intermittent". Guess I need a crank sensor! Anyone here know a cheap supplier?

Cheers,

~Chris

^^^^ key word, intermittent^^^^^
Electric faults can be a pain in the knot hole. It could be a bad connection but could also be a bad sensor. Sometimes the only thing to do is change the part.

Very good call by Shopp yet again though!

Hi Chunky,

Yes, but this 'intermittent' problem has only happened twice, and both times while starting. Why would the poor connection/sensor not be 'faulty' in 5 weeks of driving, and again after the second non-start? Surely all that vibration etc would make it misfire at some point?

~C

[chunky79]

Sometimes a crank sensor fault won't cause a fault while the engine is running.Some Izuzu engines won't start if the sensor is faulty, but if it fails while running it won't cause a fault. Not sure if that makes sense.

[chrisn6]

Good to know that Chunky. I guess it means that replacing the sensor should cure the problem! So, does this entail a complete front end strip down, same as if doing the cambelt?

~C

[bilko1]

The crank sensor(inductive pulse type) produces an A/C voltage this voltage increases with engine speed. With age and temperature change the sensor resistance changes which effects its ability to produce said voltage at cranking speed, if the voltage is too low the engine won't start. I see a lot of crank sensor faults in my work mainly Vauxhall and Renault and the occasional Ford. They are relatively easy to check if you can get to them or the wiring at the ecu, you are checking if the resistance and voltage is within spec.

[drybeer]

I'm not so mechanically savvy as some of you, but my B5 did a very similar thing years ago.

It was just a fuel line not quite tightly enough fixed on - it must have worked its way loose over the years. Once it was sorted all was back to normal.

Could it be something as simple as this?

On mine there was a faint smell of raw petrol un the bonnet on closer investigation.

[chrisn6]

The crank sensor(inductive pulse type) produces an A/C voltage this voltage increases with engine speed. With age and temperature change the sensor resistance changes which effects its ability to produce said voltage at cranking speed, if the voltage is too low the engine won't start. I see a lot of crank sensor faults in my work mainly Vauxhall and Renault and the occasional Ford. They are relatively easy to check if you can get to them or the wiring at the ecu, you are checking if the resistance and voltage is within spec.

Thanks for that info. That makes sense and explains things! Dave implied that it's a 'front end off' job, but from what I've found, the crank sensor is on the bell housing. Maybe Dave was thinking of the cam sensor? I hope I'm right and it's a relatively easy job!

Drybeer, thanks for the suggestion, but the VAGCOM did show a fault with the crank sensor and no fuel smells here.

Cheers,

~Chris

[Shoppinit]

Could also be the X relief relay. Quite common on VAG cars of this era.
I had one fail intermittently on a friend's car. I put an override switch on the relay to confirm, and next time the car wouldn't start, flipped the switch and it started right up. Nice positive diagnosis.

I did have a photo on imageshat but I see it has been randomly disappearing my images again. Useless webshite. Can anyone recommend any other hosting site? Not photofucket.

[BillTheButcher]

imgur.com

I hosted some pictures for a car ad on there four years ago and they're still there.