All of a sudden doesn't want to Idle

[Simplysmn]

Hey Guy's 93 ve motor in my crewcab running fine up untill Sunday went to get off freeway came to end of Ramp and it didn't want to Idle started shaking and the Oil light was flickering reved it back up sound's fine .Got to next stop sign same thing shaking and didn't want to Idle . got home and Started looking everything over adjusted the idle up and it sounded fine took it for a drive and when I pulled over it was idleing at 1100 rpm's so back home readjusted it . now sitting idleing it is surging .What do I need to check ? Motor has 150,000 been in truck sence 143,000 and has Ran Great ever sense . Up Untill Sunday . Could it be lift pump going out ? and reason I am not thinking lift pump is it run's fine throu the gear's and at hwy speed . Idea's or any help ????????

 

[cerberusiam]

Best guess, time for a VE rebuild. Always been the solution every time that has happened to me, if it didn't flat quit.

 

[Simplysmn]

But it Only has 150,000 it run's to good to be messed up I am leaning tward a lift pump and then go from there .

 

[cerberusiam]

150k, 20 years, running ULSD and you haven't had it apart it has been on borrowed time. Every single pump I have running ULSD eventually had to be pulled and rebuilt.

Obviously coul dbe lift pump but they usually won't start when it goes bad. Loosen the bleed screw and see if you can get it to run fuel by manually pumping it.

 

[DVolk]

Clogged fuel filter or possible geled fuel or sucking air , if your pump isnt leaking i dont think the pump . Also check to make shure your pump is tight and didnt loosen up , mine did that and pump bolts backed off . Might not hurt to by pass lift pump and hook fuel can directly to the pump

 

[Simplysmn]

150k, 20 years, running ULSD and you haven't had it apart it has been on borrowed time. Every single pump I have running ULSD eventually had to be pulled and rebuilt.

Obviously coul dbe lift pump but they usually won't start when it goes bad. Loosen the bleed screw and see if you can get it to run fuel by manually pumping it.

What would Cause this thou all of a sudden ? that's the tricky part .

 

[Bob Beauchaine]

I talked with a certified Bosch technician about 10 years ago and if you want longevity he recommended Stanadyne Performance formula to add lubricity back with the first drop in sulfur in diesel fuel. I started using it and the switched to Power Service with no noticeable down side. With the 50 PPM formula I am now looking at Enertechs products. This new Diesel formulation has some scary problems with water entrained in it that can freeze and then drops out in cold snaps below -10 degrees. For this water to go back into suspension on its own accord requires temps from 40 to over 50 degrees. Since the VE is lubricated by fuel I feel it makes sense to use a lubricity additive that will also protect the VE from as many problems as possible.

Bob

 

[Simplysmn]

Well Bob Thank you .I Live in Sunny Calif lowest it has been is 40's Latly but that's ok I also use 2 stroke oil in my fuel . so Right now I am going to change lift pump and put some fuel in it and go from there and see what happen's .

 

[cerberusiam]

Like Dvolk said, make sure the pump is stil solidly mounted. Has the same thing happen a couple times. The studs back out of the housing and lost 1 of them. The pump would move freely and that totally messed up the idle.

The other issues we have had is the PR valve that regulates pressure in the case failing. That will drop case pressure then the governor keeps trying to maintain rpm and will surge at an idle. The ULSD cause all manner of funny stuff to go on in things that were rock solid before. The valve wears and won't seat, it get crud or fuzz in it and won't seat, etc. Fill the filter with your favorite cleaner and let it work thru the system and let it sit over night. Could just be something in the fuel causing a blockage in the ports or PR valves.

Running 2 stroke oil in all of these trucks has been beneficial. A good additive like Power Service has also helped a lot with the crap fuel we get, especially in southern climates.

 

[Simplysmn]

Everything is Tight I am going for Lift pump today and see what happen's from there worst Case I end up with the Pump top off after that but we will see how it goes .Thank you All for the Info I will update you with what I find out .

 

[DVolk]

Ive been running fuel additives in all my rigs religously for years and i dont see the any issues , but yours sould like a loose pump or a clogged fuel fuelter issue or clogged line , it wouldnt hurt to rig a line up to the pump and see how she behaves .

 

[Simplysmn]

Funny thing I changed filter and so far it sound's fine no surging or acting up I do have a Lift pump on hand but when I had fliter off I hit the prime arm and it was pushing fuel within 1 pump from the filter area . So Maybe it was just a plugging fliter not sure yet but weather stopped Work on it today .

 

[DVolk]

I hope you looked inside the filter> Ive seen plastic inside of them before from the wrapper some how .

 

[Simplysmn]

I did but have not cut it open it started raining so I closed truck up n came inside . but I am going to cut it open this Morning .