1991 A100 2.3 cranks but won't start

[HeadlessChicken]

A 1991 Audi 100 2.3E sat idle for a couple of months, and the battery went flat.  Prior to this, it was in use most days and reliable.  The battery was taken out and charged, and after that the car cranks but won't start.  The battery was not reconnected wrong way round, even for a second.

Maybe taking the battery out has nothing to do with it, it could be a coincidence.  There is no alarm fob on the key, there is no alarm fitted, and I don't think it has an immobiliser, key is very simple. 

Does anyone have an idea what might cause this ?  Due to recent bereavement the car now needs to be sold, so it needs to be running.  It seems a real shame to scrap this car.

Thanks.
 

[audia4b5kev]

shame you not close to  geordie land  bud  i would sorted it for you  and probs bought off you  kev

[Magnet]

Causes could of course be numerous. 

First check would be battery. Even though the car cranks over (enthusiastically?) doesn’t mean the voltage will stay high enough to start the car while the starter motor is cranking and taking a high current through the  battery. You will need to measure the voltage at the battery when the starter is cranking over to confirm the voltage remains close to 12v. Voltages down to below 11v could result in the car not starting.

Just one possibility to eliminate first. 

Perhaps you could let us know how you get on.

Kind regards,

Gareth.

[HeadlessChicken]

2 hours ago, Magnet said:

 

First check would be battery.

Thanks for reply.

I can measure it but I'm sure it's not the battery - starter motor was turning it over way too well, no hesitation, no slowness.

We tried a tow start, it was sounding like it wanted to start, but couldn't quite get there.  If it was battery, it definitely would have started at that point...

[Magnet]

Fair point re tow start, but you didn’t tell us that before!  Detail is all important. 

As I see it you now have to determine whether you have a spark at the plugs which is good enough to start the car, and/or a supply of fuel, and get back to us - assuming of course you haven’t already checked these points. 

Kind regards,

Gareth. 

[HeadlessChicken]

Solved by local garage - replaced the knock sensor.