Rebuilt pump does not return to idle

[Lazarus]

Hello All,

Finally got around to intercooler and rebuilt pump installation. All seems well except after warm up, engine does not always return to idle, it just stays at rpm where you had accelerated to. Called my pump rebuilder and he suggested it was gummed up. Per his instructions I filled up new fuel filter with diesel cleaner conditioner, also filled up tank and added cleaner to fuel. I have driven about 300 miles it still hangs up. It is not the linkage or throttle cable!
I seems like it is fine when cold but condition returns as operating temperature is reached. It seems like it has gotten ever so slightly better with cleaner but I am not 100 percent certain. Suggestions? Has anyone else experienced this condition.

Thanks
David
82 diesel vanagon westy 1.6td intercooled

[airhead]

Well if you paid to have the pump rebuilt, the thing should work. Get back onto your pump rebuilder and tell him to sort it out.

[Wingaman]

Do you have smoke at WOT ? If not don't mess with the max fuel delivery.

Unscrew the residual fueling screw a bit (long screw where the throttle lever stop at idle).

[Vincent Waldon]

Well if you paid to have the pump rebuilt, the thing should work.

2X.... "gummed up" is a poor excuse for an answer, imho. 

There's a particular pump rebuilder on the Internet with a very very poor track record of inexpensive rebuilds that don't run properly after they have been rebuilt... to save you (and us!) some time:  perhaps you can let us know who rebuilt your pump?

[Lazarus]

Hello All,

Thanks for your suggestions. It is good food for rumination.

Airhead: You are right the pump should go back to the rebuilder. I am contemplating driving it up to see him on my day off. I am being lazy and don't want to remove pump to send to him.

Andrew: Does moving the maximum fuel screw out decrease or increase the fuel?

Wingaman: It smokes black at wot.

Vincent Walden: The pump was rebuilt last summer by Bryan of Precision Diesel in Higginsville MO. I would not start my rebuilt motor when it was first installed. He said it was gummed up and cleaned it out. (I had been burning grease and/or b100 so it probably was gunked up by that.) It sat from last October till two weeks ago. So the jury is still out on the rebuild. The other pumps (2) he has rebuilt for me have been fine. Another friends rebuild from him had problems and another rebuilder did not like Bryan's work.

So here I sit. The vanagon runs so well except for this problem. It is so much fun to have an intercooled, turbocharged micro-diesel bus that I just want to go on a road trip.

I believe I will try unscrewing the residual fueling screw a bit, that seems like the place to begin...

More later as I am on the road for work for a couple of weeks, it gives me time to think about it, before I can act on your advice.

Thanks for the help and ideas.

Peace
David

[jtanguay]

unscrew the max fuel screw 1/8 turns with the engine running and experiment by blipping the throttle.  the rpms will hang like you describe if the max fuel screw is too far out.

[rabbitman]

I had a rebuilt pump stick like that shortly after installing it.

I squirted a puddle of WD-40 into the little "dish" in the top of the throttle arm and it fixed it.

[Lazarus]

Thanks to All!

Looks like Wingman's advice worked. WuWho!! I had a chance to tweak it for 20 minutes yesterday, I have backed out the residual fuel screw 1 1/2  turns and the problem has almost completely gone away!! Will back out another 1/2 turn when I get back home for the weekend. I'm really excited to drive it some!!

Peace
David