Hi everyone,
After a days knuckle scraping its time to ask the experts!
Suddenly the car will not start...
It has spark....
The fuel pump doesn't run except with a jumper cable via the fusebox (fuse intact) but the relay seems fine, clicks with ignition on and again when starter is spinning.

Even with the pump running manually no pressure seems to build in the circuit, (ran the pump a minute, switched off and opened the fuel line but no pssssh, just a drip).
But when I try the pump running into a container the amount seems sufficient, (Sorry for the lack of hard measurement here).

Is there some sort of feedback to the pump to tell it to pump and this has gone wrong or could the pump just be faulty (but then why doesn't it run from the key but fine with a jumper?)

There is only one faultcode that reappears after clearing......
"04202 17967 Throttle Valve Control, Part J338
Fault in Basic Settings...Intermittant"
I only have the shareware version of VAG-Com so can't do the setting as per the manual but is this even related to the no start problem (Gut feeling....no)

Will try to do a proper measurement of the pumps capacity tomorrow if I can convince the wife petrol doesn't explode on contact with air.

Any help greatly appreciated,
John

 

Further to my post....
Ran the pump volume test and with 12.5V got around 700ml after 15 seconds so that seems OK?

Noticed that with the fuel circuit all back together and manually running the pump, theres a loud sshhhhhhhhh coming from the pressure regulating valve all the time, i.e. the sound of fuel going past it even though no pressure seems to build....is this normal?

Is the pressure regulator as simple as a blow-off valve that opens once a certain pressure is reached? Took it out and cleaned it but made no difference....

And also does the pump run constantly or is it controlled from the ECU to maintain a certain pressure, if so where is this detected? i.e. does the pump "know" that pressure is low and therefore pump? (Trying to understand why the pump doesn't run under any circumstances except when jumpered)

Also found that 12V is sent to the pump while cranking and petrol is pumped.....

Please help as I'm going round in circles here a bit!
P.S car ran fine up till this point..mind you I've only had it 7 days after trading in my '91 2.8 with 270000km problem free.......