Hi Guys,
Wondering if you can help with this as it's got everyone stumped so far.
The car is a VW Passat 1999 AFN 110 bhp TDi.
It's done 175K and the problems started about 3 weeks back when my friend had run the car down on fuel until the light was on and then filled it up at the local Shell fuel station.
As he was pulling away (fairly hard accel, upwards of 3,800rpm) the engine suddenly lost power, the rev counter went nuts (flipped over to max) and then it cut out.
After coasting to a stop, my friend tried to restart the engine. It would start and then stop (almost asthough the immobiliser had cut in but running for longer than the 1/2 second that allows). If you put your foot on the floor, it would start and rev to around 3,000rpm before cutting out after anywhere from 3 seconds to 3 minutes (no rhyme or reason to how long) but it'll only run if your foot is on or almost on the floor.
The car was then checked over by RAC breakdown and would run on easy start as it was sprayed into the inlet. As the car was then towed to a local garage, the glow plug light started flashing and an error code was then extracted which was 00513, engine speed sensor error.
The engine speed sensor was changed for a new VW/Audi part (along with the gearbox speed sensor just in case) but the problem remained.
The garage took the car to a local TDi specialist and they diagnosed an incorrect voltage from the ECU for the engine speed sensor and suggest an ECU change. My friend then asked me to have a look into this.
He bought a 2nd hand ECU from the local VW breakers and I plugged it in, coded it to the car and got the car running as before. The same fault code still remains and the car will only start with your foot on the floor etc.
He has now returned the 2nd hand ECU and has bought a 2nd hand TDi pump (just in case) as we're running out of options. It was only £30 more than the ECU!
I have checked the new engine speed sensor for readings between pin 1 and pin 2 and it was reading within spec. I also checked the wiring between the ECU and engine speed sensor plug. All wires check out ok.
I have also changed the fuel filter and the car had an oil service the week before and had covered 600 miles or so since the service without problem.
I've also checked the feed and return lines to the diesel pump for anything coming through which shouldn't be there and I think I remember the TDi specialists had actually bypassed the fuel filter to take that out of the equation.
Other things which are a little odd about this problem are:
I can connect to the Engine ECU when the ignition is first switched on but once you have tried to start the engine, Vag-com can't find the ECU.
The rev counter is not reading accurately. It tends to waver around a bit and sits at just over 3,000rpm when the engine is running (with WOT). I'd estimate that the engine is revving around 2,800rpm.
The only way I can read anything from measuring blocks within vag-com is to go into measuring blocks while the igntion is switched on but before I start the engine. Then start the engine and I can then go through measuring blocks to see if there's anything odd going on. The revs register close to 5,000rpm when the engine is running but, at the point at which the engine dies, vag-com looses all rpm data.
I'm not usually one to admit defeat but this is one I haven't come across before. I didn't have time to change the TDi pump today and didn't have a puller which me to remove the pump pulley.
Does anyone have any ideas?
Thanks.
Michael Ghia