Truck runs great but will not idle at stoplight...

[84TD]

Hey guys, this is on my friends truck, it runs and drives fine but it will die out when the throttle is let off coming up to a stop. It will idle when started fine and if you let of really slow it will idle but if you let off quickly like coming up on a quick stop it dies out. He did fill up this morning so we are thinking it could be fuel quality related but is that really plausible? We had the ip rebuilt when we rebuilt the engine a few months ago.

BTW his truck is the 1984 f350 6.9 C6 4x4 DRW flatbed

 

[Devon Harley]

Add a large dose of ATF to the tank like a quart to 4-5 gallons an remove an fill the fuel filter with ATF. Start it wait for the engine to get extremly quiet shut down over night or for 5 hours an re-start. Sounds like a STICKY meter valve!

 

[gandalf]

I'll second that opinion about a sticking metering valve. Dose it with straight ATF. The objective is to have the ATF sit in the IP overnight. If that doesn't clear it up, I'd question the rebuild procedure.

 

[icanfixall]

Both the oppinions above are what I feel also. Who did the pump rebuild. What is the idle set for. It should be about 650 rpm. I like mine at 750 rpm but thats me...

 

[Dzlnut]

I got some advise by a local fuel shop and I did it to my pump today. My engine would die after reving it up as well. On the rear of the pump, above where the injector lines attach there is a allen head bolt with a jam nut. My jam nut was 1/2 inch wrench, loosen the jam nut and turn the screw in 1/2 a turn. The shop advised me that more than 1 turn would raise the idle. I did this to mine and the problem is resolved, engine goes to idle at after throttle is released.

Do This at your own risk.... It worked for me, it may not for others.

 

[84TD]

It would seem that the metering valve would have been **** and span after the rebuild. We added and entire bottle of total power to the front tank and drove it, it seemed to be ok for a day but then seemed to get worse the next. The truck did this once before about a month ago for approx 1 day and then went away. Its strange.

Doesnt it seem to reason if the pump had an issue it would do it 100% of the time?

Dzlnut was your problem somewhat intermitint or all the time?

I think what I might do is raise the idle to 1K just to get through this tank and go from there. At least that way I can rule out fuel.

 

[Black dawg]

It would seem that the metering valve would have been **** and span after the rebuild. We added and entire bottle of total power to the front tank and drove it, it seemed to be ok for a day but then seemed to get worse the next. The truck did this once before about a month ago for approx 1 day and then went away. Its strange.

Doesnt it seem to reason if the pump had an issue it would do it 100% of the time?

Dzlnut was your problem somewhat intermitint or all the time?

I think what I might do is raise the idle to 1K just to get through this tank and go from there. At least that way I can rule out fuel.

That is what I usually do, raise the idle speed for a bit, overdose with cleaner.

 

[Dzlnut]

Mine was all the time and raising the idle did not help. Snap the throttle and release it would die.

 

[84TD]

It looks like bad fuel guys, it was still doing it some on the second fill up, we changed the fuel filter and it was all rusty inside so I think he got some watered down fuel at exxon. It seems to be getting better.