GTi Wont Start; looks like electrical faults around the Hall and temp sensors.

[Dyno Soar]

Hi there, I am newbie to this forum,  I bought my wife a cool little non turbo 99 Golf GTi 1.8 20v Auto (she prefers it for london traffic).

Anyway we have been having really poor gas milage in it and it recently starting to have a hard time firing up in the cold mornings.  It would kind of judder and the idle would be all lumpy.  When it was warm everything would be ok after that.

Also the water temp guage became erratic in its function.  Sometimes it would come on and sometime it would not work at all.

I went to start the car early in the morning and nothing.  It cranks but it won't fire at all.  The car won't start at all now.  It justs cranks but won't run.

Does anyone have an idea why this could be?

I used the search and tried to find out similar probs.

Temp gauge not working - poor milage - bad starting...Could it be the water temp sender that sits in the engine block?  Apparently I should change it for a 4pin green top if I have the correct connection.

I don't have a VAGCOM but I bought a Sealy full diagnostic from GS&F for £150.  I'll try plug that in and see if I have any fault codes.


What is the sensor that is coming from the T-piece section where the thermostat is located? 



I hope after reading up I hope I am on the right track.. if you guys have any other advice then please let me know.

Thanks AL 

[topher]

most likely the temp sender. it isn't in the block though it sticks out the top of the rad hose that comes out the right hand side of the block (looking at it from the front)

[Dyno Soar]

Hey thanks for the confirmation.  I'll try to get access to it tonight so I can see if I have 4 pin green top connection.

I am really hoping that this will slove the problem.

Cheers
Al

[Dyno Soar]

Argghhh damn car...

I changed the temp sensor (my car has a blue one) and the bloody thing still wouldn't start.   

I shelled out some big notes for a Sealy VAG COM diagnostic unit.  I thought it would be good to have and as loads of my mates have every model of VW i'd be the hero saving them so dough with the tool.

Anyway I wasn't overly impressed with the tool but it did seem to give me some results in the end.

1. Managed to reset the service indicator, however the service alarm that goes 'ding ding ding ding...' is still going off when I start the car.   


Ok so I found the following codes:

Engine;

00515  (029)
Hall Sensor (g40)
Static short circuit to earth.


also

Instruments:

Water Temp Sensor  (G2)
Sporadic connection
short circuit to earth


So questions...

1. does this mean I have to take the car to a auto electrician to have the short circuits sorted?

2. Should I go to a VW specialist or auto electrician or can any garage handle this issue?

3. Or can anyone offer me any advice so that I can fix this problem myself? My prefered choice.


................


Coincidently the chap at Heathrow GS&F was telling me it could also be the MAF (part 18785)  £44
Or the O2 sensor. 
Could it be he was just trying sell me parts?

Help.. really need the wife GTi back on the road 

[richw911]

Argghhh damn car...

I changed the temp sensor (my car has a blue one) and the bloody thing still wouldn't start.   

I shelled out some big notes for a Sealy VAG COM diagnostic unit.  I thought it would be good to have and as loads of my mates have every model of VW i'd be the hero saving them so dough with the tool.

Anyway I wasn't overly impressed with the tool but it did seem to give me some results in the end.

1. Managed to reset the service indicator, however the service alarm that goes 'ding ding ding ding...' is still going off when I start the car.   


Ok so I found the following codes:

Engine;

00515  (029)
Hall Sensor (g40)
Static short circuit to earth.


also

Instruments:

Water Temp Sensor  (G2)
Sporadic connection
short circuit to earth


So questions...

1. does this mean I have to take the car to a auto electrician to have the short circuits sorted?

2. Should I go to a VW specialist or auto electrician or can any garage handle this issue?

3. Or can anyone offer me any advice so that I can fix this problem myself? My prefered choice.


................


Coincidently the chap at Heathrow GS&F was telling me it could also be the MAF (part 18785)  £44
Or the O2 sensor. 
Could it be he was just trying sell me parts?

Help.. really need the wife GTi back on the road 

To rerset the service indicator look at this:

http://www.golfgtiforum.co.uk/index.php?topic=62717.0

[Dyno Soar]

Yeah I read how  to do that in the manual.  Thanks tho... no real need for the VAG COM tool huh?

I think the key difference is my car was telling saying 'inspection' rather than 'service'  perhaps its because the computer realised I have other issues.


Any advice on the fault codes and errors I have would be apprciated. 

Cheers

AL

[Dyno Soar]

Looks like I have you guys stumped.  One garage has already said they don't want to know.

Looks like I'm all by myself  on this one..

Al 

[ub7rm]

I don't know where the Hall sensor is but you might try finding it and tracing the wires back as far as possible and look for any obvious splits in the insulation etc.  Its not a common fault as such but I have certainly heard of hall sensors failing - I don't know how expensive they are but it might be worth replacing it to see if this solves the problem? 

Don't know if you've seen this but:
http://wiki.ross-tech.com/index.php/00515

I think the GSF guy was trying to sell parts, the two he mentioned are very common problems so he would have been basing that comment on how often he sells em.

[meg1980]

Try crankshaft sensor i think it is located at the bottom of the engine block behind the oil filter housing or it could be the camshaft sensor behind the camshaft wheel. Hope this helps let us know end result.Cheers.

[ub7rm]

Yeah Hall sensor is another description for the camshaft sensor.