Hi all.  I left an x reg 6N2 on my pals land with the intention of getting a fresh MOT on it this year and selling it.  It has sat doing nothing for a couple of months and predictably had a flat battery today.   Using a fresh battery it would not start.

 

The problem seems to be linked to the ECU or some kind of wiring which instinctively I think is linked to the car probably getting damp from condensation.  When turning the ignition key it just seems that there is no fuel delivery and we don't think it is a fuel pump issue.  When the key is turned to the full crank position the engine will fire but once you allow the key back to the idle position nothing - the car will not continue to fire.   

 

I am hoping that someone has experienced something like this before - I intend to run a heater on the interior for a few hours to encourage everything to dry out.   Any thoughts please?

Hi all - well that you all stumped as indeed it had me. No responses.

 

 

About 3 years ago I replaced the ignition coil pack just as part of a general upgrade including new plugs and leads.   Fortunately I kept the old one even though it was not performing at 100%.  Where there you have it - I put the old coil on and the car started.  It seems that the coil had broken down and the ecu must prevent fuelling when it senses no spark.  The odd thing was that it was firing when the key was turned to the crank position.   Next point of interest - will the ebay seller honour the 5 year warranty on the coil I bought just 3 years ago?   

 

Cheers all

Not sure how ECU senses a spark... it usually asks for a spark at a time BTDC from cam or crank sensor.

(though Saabs had ionizing circuitry to detect cylinder state The Saab TRIONIC Was Ahead of Its Time - Saab Cars Blog (saabplanet.com) I'm not aware of VWs using it. 

 

With weak spark I'd expect it to fire as you released the key from cranking because current no longer flowing into starter motor, so a bit more volts and oomph for the coil.

 

Have you measured primary and secondary resistance of the 2 coils?

I'd be checking earth connections for corrosion.

.

 

 

Suffice to say I am no expert but equally sufficient is that I was delighted that the old coil pack worked.  Taking it for MOT pretty soon and may run it locally as it is so cheap on fuel albeit low on street cred (like that matters!!).  Pleased that the battery seems to have revived too.  The whole firing when cranking thing is interesting and I hoped that someone out there would have pointed to my lack of sense and told me the "obvious" answer.  Happy it's running - it came close to the scrap yard!

Edited 12 January, 20233 yr by DerekR