'99 TDI (AFN engine) - misfire at high RPM

[adam harris]

Hello folk.
Bit of an odd issue - we have a 1999 "3B" shape Passat estate with the (usually) trusty basic AFN tdi engine, and 185,000miles.
always properly serviced by last owner (who had it for 18 years!) and according to the history a "full service" about 2 years ago / 10k ish miles (guessing that included the fuel filter)
Today, my wife used the car, got to her destination no problem, went to start it to come home and it just cranked, but didn't fire.
I went out to it and sure enough, cranking but no attempt to fire at all - plenty of fuel (put fuel in yesterday). I checked the usual stuff, even wired the fuel stop solenoid direct to the battery to make sure it wasn't that, - still no joy.
Took off an injector feed pipe at the injector, a bit of fuel coming out when cranking but I wouldn't say enough.
I did wonder if it might be the lift pump, but it turns out that AFN engined cars don't have a lift pump!... I was about to give in and call the RAC to relay me home, thinking that the Injection pump had died, but before I called thought I'd try her again...she cranked, and this time fired on one cylinder.. then two then came to life! almost as if she'd been run dry on fuel.

so, all good, but now when reved up over 3000rpm with foot hard on the floor she starts misfiring, enough to almost think she's going to die, but it never does - drive it normally (read 'steadily') and she drives fine...... any ideas?
-pump dying?
-poor fuel? (Sainsburys)
-fuel filter? - although I'v had blocked fuel filters before and it just showed itself as a lack of power instead of a misfire.

Cheers n gone
Adam
Cornwall

[Vagnuts]

Hello folk. Bit of an odd issue - we have a 1999 "3B" shape Passat estate with the (usually) trusty basic AFN tdi engine, and 185,000miles. always properly serviced by last owner (who had it for 18 years!) and according to the history a "full service" about 2 years ago / 10k ish miles (guessing that included the fuel filter) Today, my wife used the car, got to her destination no problem, went to start it to come home and it just cranked, but didn't fire. I went out to it and sure enough, cranking but no attempt to fire at all - plenty of fuel (put fuel in yesterday). I checked the usual stuff, even wired the fuel stop solenoid direct to the battery to make sure it wasn't that, - still no joy. Took off an injector feed pipe at the injector, a bit of fuel coming out when cranking but I wouldn't say enough. I did wonder if it might be the lift pump, but it turns out that AFN engined cars don't have a lift pump!... I was about to give in and call the RAC to relay me home, thinking that the Injection pump had died, but before I called thought I'd try her again...she cranked, and this time fired on one cylinder.. then two then came to life! almost as if she'd been run dry on fuel. so, all good, but now when reved up over 3000rpm with foot hard on the floor she starts misfiring, enough to almost think she's going to die, but it never does - drive it normally (read 'steadily') and she drives fine...... any ideas? -pump dying? -poor fuel? (Sainsburys) -fuel filter? - although I'v had blocked fuel filters before and it just showed itself as a lack of power instead of a misfire. Cheers n gone Adam Cornwall

by the sounds of it ,"its struggling to draw enough fuel when under load"---lift pipe inside the tank can/and do's get choked over time even with this so called "clean pump fuel"--obviously fuel filter first, but if it no better I would take tank sender/lift pipe out and on the end of it t you will find a small triangle shaped gauze !!--clean it, and if that no better I would sat that your VE pump lift diagram is/has given up the ghost !! new/ recon/scrappy for a pump !!! as an after thought might be worth blowing down the feed pipe--as there could be a very small pin hole allowing air to be drawn in under load !! Just a thought --seen it be fore !!!! So did you get any further forward with it ???-def sounds like fuel starvation under load !!!

[micheal balbrig]

Last fill up may be dubious ?.