Cold Starting Firing Issue!

[Fat Audi 80]

Hi Chaps,

My normally ultra reliable S2 has started to play up. I have literally seen this about 3 times in the last 2 years but yesterday and today it has happened twice and worse.

The engine turns over perfectly and strongly but does not catch. It did it last night while I was out and I managed to start it after cranking half a dozen times. Tonight, I have cranked the car until it went flat and it refused to start.

No, I have not pulled the codes, I have never had to on my car and am a little unsure of what to do.

Does this ring any bells with anyone?

I am going to try the water down the back of the cambelt trick tomorrow when the car has charged again, but in the meantime can anyone offer any other advice.

(It has had the crank position sensor (called TDC sensor) changed in the past due to non starting, but that was in '99 ! )

Cheers,

Steve.

[Knight Rider S4]

Fuel pump relay ......have you got vag.com on laptop and the leads to plug into car?

[Jas11n]

Whats it like starting on a hot engine Steve?

[Fat Audi 80]

Would not start this morning - 4 cranks - nothing.

Dribble of water down the back of the cambelt - Fired instantly.

I am assuming this is the TDC Sensor / Cranks Pos Sensor. Are they the same thing?

How difficult is this to change?

I am going to keep an eye on it, if it gets any worse at all I will have to change it.

Thanks for the replies chaps!

Cheers,

Steve.

[Rusty]

to my world

Sorry i can't solve this with a wave of my hand, I'll be watching this with interest...

Hope you get it sorted. Is the car running OK apart from that?

[S2central.net]

Tis a big enough job that CMP sensor - timing belt loosened and cam pulley off. Care required with the cam pulley so you don't damage its key onto the camshaft. Don't think there is an official locking tool for this job - a blummin big spanner that tightly fits some flats on the camshaft is sufficient - need to do that for loosening and tightening the cam pulley bolt.

One quick way to verify the CMP (G40) is working is with an LED test lamp - connected across pins 1 & 2 of G40, you should see it flash on every 2nd engine revolution when you crank the starter.

HTH

[PeteRR]

Would not start this morning - 4 cranks - nothing.

Dribble of water down the back of the cambelt - Fired instantly.

I am assuming this is the TDC Sensor / Cranks Pos Sensor. Are they the same thing?

How difficult is this to change?

I am going to keep an eye on it, if it gets any worse at all I will have to change it.

Thanks for the replies chaps!

Cheers,

Steve.

Sounds for all the world like it's the Cam Position sensor (or Hall sender as it's also called). Mine went recently and was replaced (not be me though) by carefull removal of the Cam Pulley.
Get it done sooner rather than later though Steve. I've heard that the water trick only works for a short time so you don't want to get stranded somewhere!

[ericd]

Steve, reseat/clean the connector , you have'nae been cleaning round the front of the engine ?, had the same problem once about 3 months ago , had replaced small vacuum hose at front and removed the plug connector underneath when I was there for ease of access, must have seated it badly , but it did seem to have some residue /gunk in it , not suprising considering where it sits, think removing/reseating it without cleaning the connector might have forced some more junk in to it..

worth a try and look , only takes a minute.

HTH


p.s.

drive it more often, clean it less

[S2central.net]

p.s.

drive it more often, clean it less

Contraversial

[Fat Audi 80]

Thanks for the input guys.

@Eric,

No I haven't been cleaning around there! (yet)

I will check and clean the connector and go from there....

Cheers,

Steve.

[S2central.net]

The same kind of LED for blink tests can be used to check G40 - tricky bit is packaging it in such a way as to connect nicely to pins 1 & 2 at the connector. Oh and it will only work one way round cos its a LED. Dunno what kind of voltage to expect from a hall sender - cant remember. I should really look at it that waveform with an oscilloscope.

Paul

[S2central.net]

This works nice with a lil LED that I have for blink tests. You need to tease back the hood on the connector for G40 to expose the three pins. Pin 2 is in the middle (funny enough) and pin 1 towards the bulkhead. You need the cathode leg of the LED on pin 1 - its a wee bit fiddly teasing those little legs in, but they do make sufficient contact for a useful signal.

No batteries in my sillyscope, so that will have to wait.

[Flat on my back]

Might help?

http://www.s2forum.com/forum/showthread.php?t=21769

[Fat Audi 80]

http://www.s2forum.com/forum/showthread.php?t=21769

ABY...

[Flat on my back]

Troublemaker...

Same sensors, different position for the hall sender, off cam instead of dizzy.

Jpeg at end gives idea of shapes when working.

Good luck.