Archived 2001 just stopped, all else seems ok

[comm-tech]

New member here..... First the truck... 2001, Dodge 2500, Quad Cab, 4x4, auto trans, 155,000 miles, all stock. Has the engine mounted lift pump which was replaced about 2 years ago (and the truck knew there was a LP pressure problem and threw some codes). Now the problem... The truck was running fine, I made a right turn going to work and it just quit. No missing or surging, it just quit. Cranks fine, no codes, opened the filter drain bumped the starter and a reasonable amount of fuel came out, still no start. Had it towed home.



What I've done... . I've checked the pressure before and after the filter. At first I wasn't getting any pressure so I opened the filter drain... . NOW not getting any fuel. So I go get 5 gal of fuel just in case (wouldn't that be a pleasant surprise). The gauge was reading almost a 1/4 tank (well above where it has run out before) but just to be sure..... added the 5 gal to the tank. Now with the LP inlet connected to the tank, bump starter, still nothing... . then I opened the filter drain, hear the LP start to load and fuel comes out, close drain and pressure builds to about 14psi. With next starter bump same thing... . Repeated this a couple of times with the same result, no pressure until I open the filter drain and let it move some fuel. I can hear the pump running and hear it start to load when it starts moving fuel. Only starts to load after I open the filter drain. Do I have a leak in the fuel line going to the tank or a leak IN the tank in the pickup line??? Maybe a weak LP? So I get another jug of Diesel and feed the LP inlet from that. With starter bump about 14 psi. Drops to about 10 during cranking. Opened the fuel filter drain and there seems to be a decent amount of fuel coming out. Ok, so I'll get it running then address the fuel supply issue. On to the injector pump. With the tools that I have available I was only able to get one injector line cracked. (Looks like I need to find a 3/4 tubing wrench or a box wrench with an opening). Anyway, fuel seems to come out whenever the lift pump is running. Is this normal for a VP44? It was getting late so I quite for the night.



Is there anything that can tell the computer to shut off the fuel (oil pressure), or something like a cam position sensor or crank sensor that can cause a no run (remember no codes are set)?



Are there any starting aids that CAN be used with the CTD without destroying something? I'd like to give it a shot of ether but I know that badness can occur.



Karl M.

 

[FourBarR]

ether is bad news with the grid heaters operating,those things get really hot. Lift pump can be bad even if it is running. I have replaced 4 pumps had one new one dead out of the box. with a good pump and the fuel filter open you should get a strong flow of fuel. Hope this is of some help.

 

[comm-tech]

I do get a strong flow of fuel with the drain open. But it doesn't build pressure until I open the filter drain and let it move a little fuel. But I don't think that's the main non-run problem. First I want to get it running again. I just want to eliminate all other possibilities before spending $1500 :{ on a new VP44 injection pump. And ya oughtta see what I'm driving in the mean time . But it beats the heck out of being on hoof.

 

[p-Bar]

Are you monitoring the pressure while trying to start? The VP requires fuel to keep them cool, you trash them with no fuel.
Can you by pass the fuel system and rig up something externally for troubleshooting?
Commtech copy?

 

[Mundgyver]

One thing to be aware of is that the VP has a 14 psi return fuel port on the input side of the pump. This port has a small vent hole drilled in it to allow any excess fuel and air to be bled back to the tank during normal operations. If your fuel line is filled with air to the VP it can take some time to bleed out this air. You can crack the input fuel line to VP loose and then prime the line and re-tighten the line. Then try and get a start. I have never ever had to crack an injector line when I have had to recharge my fuel system. I just crack my VP inlet line and bleed the air from there.



Food for thought

 

[comm-tech]

When the LP is connected to the truck's fuel tank the pressure drops to near zero while cranking. But when I feed the LP from the jug starter bump yields about 14 psi and cranking is about 10 psi. So when I feed it from the jug I get decent pressure from the LP. It still won't start. It flows fuel from the one injector line on the VP44 that I was able to get loose as long as the LP is running even without the engine cranking. Are the VP44 injection pumps supposed to flow fuel even with the engine NOT cranking? I'll get another wrench and get 2 more of the lines cracked on the VP44 in a few days. But to me it doesn't make sense that the VP44 should have fuel coming out of it all the time. And if necessary I do have an electric fuel pump lying around that I can use to supply fuel to the filter and inlet side of the VP44. However past experience has taught me that the engine will run without the LP unless there is air in the system.

Ok. . good point about bleeding the inlet line. I'll try that. I've run it out of fuel a few times (empty is NOT zero on the gauge) and I've just cranked it until it started. And what you are talking about is an orifice not a regulating valve that requires 14 psi to open? So about how many starter bumps does it take to get the fuel filter, inlet side fuel lines, etc. purged if you run it out of fuel?

The only reason though that I've cracked an injector line is to see if I'm getting fuel out of the VP44. And it does... . all the time. But I guess to make sure I need to crack a couple more injector lines loose.

Karl M.

 

[JLandry]

Comm-Tech,



Sorry of I missed it and you took care of this already, but have you replaced the fuel filter?



Here's my line of thought...



If the fuel filter is almost completely clogged, I think you would still get fuel from the filter housing drain because it's on the inlet (tank) side of the filter. This could explain why the lift pump would work when you relieved some pressure from the filter housing by opening the drain valve, yet it would stop when you closed the drain valve.



At ~$12, it can't hurt to give that a try.



Good luck,



John L.

 

[Mundgyver]

This is what you have. Right out of the Bosh Service Manual for these VP's.

There is a precision drilled orifice just below the ball regulator. I agree with the changing out the fuel filter also.



Pressure-control valve

The fuel pressure created at the pressure outlet

of the vane-type supply pump depends

on the pump speed. To prevent the pressure

from reaching undesirably high levels at high

pump speeds, there is a pressure-control

valve in the immediate vicinity of the vanetype

supply pump which is connected to the

pressure outlet by a bore (Fig. 1, POSe 1). This

spring-loaded slide valve varies the delivery

pressure of the vane-type supply pump according

to the fuel quantity delivered. If the

fuel pressure rises beyond a certain level, the

valve plunger (Fig. 2, POSe 3) opens radially

positioned bores (6) through which the fuel

can flow via an outlet (4) back to the intake

port of the vane-type supply pump.

If the fuel pressure is too low, the pressurecontrol

valve remains closed and the entire

fuel quantity is pumped into the distributorpump

intake chamber. The adjustable tension

on the compression spring (2) determines

the valve opening pressure.

Overflow valve

In order to vent and, in particular, cool the

distributor injection pump, excess fuel flows

back to the fuel tank through the overflow

valve (Fig. 3) screwed to the pump housing.

The overflow valve is connected to the

overflow valve (4). Inside the valve body (1),

there is a spring-loaded ball valve (3) which

allows fuel to escape when the pressure exceeds

a preset opening pressure.

In the overflow channel to the ball valve,

there is a bore that is connected to the pump

overflow via a very small throttle bore (5).

Since the overflow valve is mounted on top

of the pump housing, the throttle bore facilitates

automatic venting of the fuel-injection

pump.

The entire low-pressure stage of the fuelinjection

pump is precisely coordinated to

allow a defined quantity of fuel to escape

through the overflow valve and return to

the fuel tank.

 

[comm-tech]

Wellllll... . I'm getting the same readings on BOTH sides of the fuel filter. So it's not the filter. And the filter is pretty new. Less than 3000 miles. And if the filter is clogged the LP should still make pressure on the inlet side of the filter housing. I want to get it running then I'll deal with the fuel from tank issue. The LP works fine when fed from a jug of Diesel...

Still haven't found out if the VP44 is supposed to have fuel running out of the injector ports without the engine turning.

I'm suspecting the VP44 wants me to spend $1500 to replace it. I want to be really sure before I do that... $1500 is allot of money for me.

 

[EBung]

When my VP went I had no indication. nocodes no miss no nuthin. Just died and never even popped again until it had a new pump. I went to the dealer and gave me a plug in harness with a red and a green light on it and told me to plug it in to the VP44 and if I got a green light it wasnt the VP and if I got a red it was. I got a red light while cranking it over.

 

[DCreed]

Bad news: there is a diaphram that separates the high and low pressure of the 44, evidently yours no longer does. Also you lift pump is junk.
so whats the good news? Mid West Fuel Injection has a good deal on VPs. Diesel performance parts and accessories. Diesel injectors, pumps, filters, kits, additive, gauges and apparel.

 

[Mundgyver]

Where exactly is this Diaphram? In the cutaway pictures that I am looking at in the Bosh Factory Manual, nothing presents itself as a Diaphram. My curosity runs amoc

 

[DCreed]

I took this excerp from the blue chips site. "There are three things that WILL VOID this warranty. One is contaminated fuel, which is becoming all too prevalent as we switch to ultra low sulphur fuel, the second is if you break the diaphram in the front of the injection pump ( this can ONLY be due to low fuel pressure ) and thirdly if you make a "nick" in the solenoid wire by hooking up a fueling style performance box. " hope this helps. FASS talks about this in thier hard start FAQ.

 

[Mundgyver]

I saw that, but I am still trying to figure out where this thing is inside the pump.