Danno
New member
- Joined
- Dec 12, 2001
- Location
- Edinburgh Scotland
I hope you guys can help me with a problem with my June 1995 Passat 1.9 Tdi Estate, (1Z Engine). I’ve recently acquired it, its done 210,000 miles (quite a few for a Limey car). I haven’t any history on the car.
The fault: When on the over-run, coasting, the car hunts several times as it drops through about 1750 rpm. It’s just enough to take up the backlash in the transmission and drive the car for a fraction of a second. It happens about twice a second. It’s very slight & seems to happen at about 1800 revs when the car is cold, (30 degrees), but is much more pronounced when the car is hot & can carry on down to about 1500 rpm. If you’re going downhill the car will carry on snatching for as long as the revs stay between 1750 to 1500. It’s engine speed related, not road speed (it happens in any gear). It also hunts a little dropping through 1050 rpm, which I think is the same fault, but perhaps this is part of the idle strategy of the software, anyway it’s much less annoying.
In all other respects: starting, performance & economy the car is fine.
The snatching is a real pain!
I’ve had it to the local WV agent for a fault-code read-out; they don’t seem to call it VAG-COM over here. The only fault found was “01268 Quantity adjuster-N146, control difference sporadic”. I gather that the quantity adjuster “moves the modulating piston on the high pressure piston in the injector pump and this regulates the amount of fuel injected”. The VW agent can only offer to fit a new injector pump assembly.
I’d expect the ECU to stop the pump fuelling under any circumstances when the car is on the over-run, so I suppose this tends to confirm that the fault is in the pump itself. I’d really like to know exactly what’s causing it. Is it possible to remove what appears to be the actuator assembly (incorporating the quantity adjuster?) on the side of the pump, it’s secured by 3 Torx screws and one anti-tamper (!) triangular-headed screw? I always dread removing something like that just in case it detaches something fiendish inside. If this is the quantity adjuster and if it can come off easily, then I can try a bit of crafty substitution with one off a pal’s similar car. Ultimately I expect I could swap pumps but obviously that’s a hell of a lot more hassle. (His pump and actuator have the same part numbers as mine but not his ECU).
Really hope you can help out with some ideas on this fault on what is otherwise a fabulous car.
The fault: When on the over-run, coasting, the car hunts several times as it drops through about 1750 rpm. It’s just enough to take up the backlash in the transmission and drive the car for a fraction of a second. It happens about twice a second. It’s very slight & seems to happen at about 1800 revs when the car is cold, (30 degrees), but is much more pronounced when the car is hot & can carry on down to about 1500 rpm. If you’re going downhill the car will carry on snatching for as long as the revs stay between 1750 to 1500. It’s engine speed related, not road speed (it happens in any gear). It also hunts a little dropping through 1050 rpm, which I think is the same fault, but perhaps this is part of the idle strategy of the software, anyway it’s much less annoying.
In all other respects: starting, performance & economy the car is fine.
The snatching is a real pain!
I’ve had it to the local WV agent for a fault-code read-out; they don’t seem to call it VAG-COM over here. The only fault found was “01268 Quantity adjuster-N146, control difference sporadic”. I gather that the quantity adjuster “moves the modulating piston on the high pressure piston in the injector pump and this regulates the amount of fuel injected”. The VW agent can only offer to fit a new injector pump assembly.
I’d expect the ECU to stop the pump fuelling under any circumstances when the car is on the over-run, so I suppose this tends to confirm that the fault is in the pump itself. I’d really like to know exactly what’s causing it. Is it possible to remove what appears to be the actuator assembly (incorporating the quantity adjuster?) on the side of the pump, it’s secured by 3 Torx screws and one anti-tamper (!) triangular-headed screw? I always dread removing something like that just in case it detaches something fiendish inside. If this is the quantity adjuster and if it can come off easily, then I can try a bit of crafty substitution with one off a pal’s similar car. Ultimately I expect I could swap pumps but obviously that’s a hell of a lot more hassle. (His pump and actuator have the same part numbers as mine but not his ECU).
Really hope you can help out with some ideas on this fault on what is otherwise a fabulous car.