Failing Lift Pump?

Ansley Rover

Ansley Rover

Active member
I rebuilt my 1993 200tdi and it's been running great. Until very recently, it started on the flick of the key. Recently, and only sometimes (maybe 25% of the time), I have to stay on the ignition for a couple/three seconds to get it to fire up. Once it did, I had no problems. Based on that, I was already thinking the lift pump may be going. This morning it did that and then after dropping the kids off at school, I was sitting at a light on a steep hill and at idle, the motor started acting like it was being starved for fuel and wanting to cut out. I pumped the accelerator a bit and it came back to life then wanted to die again when I let off. I repeated that for two or three times and then it settled out.

It seems to me like the fuel is draining back to the tank at idle. I don't have any problems on flat ground or while moving. I am assuming that the lift pump is failing and that the fuel injection pump is strong enough to pull fuel on its own which is why accelerating fixes the problem. Does this sound right to y'all? I did not put on a new lift pump when I rebuilt the motor. I believe the previous owner had though.

I wanted to get your input before I start throwing parts at it. Appreciate your thoughts.
 
saetaes

saetaes

Member
Others here have much more expertise than I do, but when my lift pump failed it was spewing diesel all over the place and didn't really have any other, more subtle, side effects.
 
G

Giftshopduane

Well-known member
Its a sound theory, cheap fix, cheap insurance tbh.. I picked up a batch of watery gas this year.. that did some funky things
to my truck. Change out your filter, also or for now Drain it and check it.
 
DefendersNW

DefendersNW

Well-known member
Ansley Rover said:
I rebuilt my 1993 200tdi and it's been running great. Until very recently, it started on the flick of the key. Recently, and only sometimes (maybe 25% of the time), I have to stay on the ignition for a couple/three seconds to get it to fire up. Once it did, I had no problems. Based on that, I was already thinking the lift pump may be going. This morning it did that and then after dropping the kids off at school, I was sitting at a light on a steep hill and at idle, the motor started acting like it was being starved for fuel and wanting to cut out. I pumped the accelerator a bit and it came back to life then wanted to die again when I let off. I repeated that for two or three times and then it settled out.

It seems to me like the fuel is draining back to the tank at idle. I don't have any problems on flat ground or while moving. I am assuming that the lift pump is failing and that the fuel injection pump is strong enough to pull fuel on its own which is why accelerating fixes the problem. Does this sound right to y'all? I did not put on a new lift pump when I rebuilt the motor. I believe the previous owner had though.

I wanted to get your input before I start throwing parts at it. Appreciate your thoughts.
Click to expand...
Lift pump failure is usually a loss of power at rpm, to the point where the vacuum from the injection pump is the only thing keeping the truck running (Idle but no throttle) - not that it cant be lift pump but instinct says look at the fuel, fuel filter, injector lines, injectors, valves, and timing. Leaks either fuel out or air in. Everything after the injectors is moot so start at the fuel filter and go from there.
 
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