Fuel Pressure Limit for the VP44

[Vaughn MacKenzie]

What amazes me is that D/C doesn't bother with so much as a pressure switch and idiot light to CLUE IN the owner in the event of a lift pump failure #ad
. We go through all the trouble with a nice little WIF (water in fuel) sensor but make no provisions whatsoever for a common and known failure in order to protect something that is more expensive than many engines! It's like running a motor with no oil pressure gauge lubed by an ELECTRIC oil pump with a high failure rate. Doesn't make a lot of sense, does it?

While on the topic, what about all those tens of thousands of poor souls that are not clued in to TDR who are having or will have injection pump failures caused by faulty lift pumps and they are out of warranty (or scammed out of the warranty)? There are thousands of non-mechanically or diesel-literate types out there driving Dodge/Cummins that are going to get reamed on this situation (and many who already have I'm sure #ad
) I'm not clued into the legal system much, but I wonder if something like this would be a candidate for a class-action lawsuit??

Well anyway, I don't think I'm going to bother with a pressure gauge but will wire in a simple pressure switch to turn on a dash-mounted LED anytime my pressure drops below 5-6 psi.

Vaughn

 

[B. Gill]

i agree with you vaughn,how many times have the WIF feature been of any use so far? not even once in my case but i have gone thru 2 lift pumps once walked 5 miles home at 11:00 pm and these things have a way of happening,i did not have the cell phone with me,2nd time i limped back home slowly.
yes light will work fine but IMO a guage is the way to go. i am working on a solution to the lift pump problem also as are others,that when the lift pump fails,you flip a switch to the other position and the auxilary lift pump comes on and you are not stranded i will post if it is someting that will work.
bob

 

[TowPro]

Vaughn, I think your on to something here! I wanted a gauge, but not at the expence they cost, I will have to get an oil pressure sensor and test its on/off pressures to see if this idea will work. I bet we even find one that screws right into the filter housing!

Its an easy hookup, most of these switches ground the output at low pressure, just run that lead to the negative side of a bulb, and wire the positive side of the bulb to a switched source.

Think I will do this this weekend. I will mount a small panal light in the shifter console, below the shifter boot, next to my BD brake switch

Originally posted by Vaughn MacKenzie:

Well anyway, I don't think I'm going to bother with a pressure gauge but will wire in a simple pressure switch to turn on a dash-mounted LED anytime my pressure drops below 5-6 psi.

Vaughn

 

[B. Gill]

Towpro,yes it might work but the oil pressure sender is rated at much higher pressures and the lift pump max. pressure is 14 (if i am not wrong) and is mostly lower than this,meaning that it maybe working ok and the light will come on causing a false alarm. if you can plumb the fuel line in the cab as i have,inside a plastic tube,(there is a thread dealing with that)and chances of it leaking inside the cab are very small if it is done right with a snubber at the connection from filter or pump to the guage,and the cost is not much i have an Autometer and it cost me less than $40 and is working fine. but you can always try diffrent ideas and see if they work #ad
. let us know if you experiment with the oil pressure sender unit.
thanks
bob

 

[TowPro]

I thought an oil light came on around 5psi or so, I was going to call my buddy (who knows more about Chevy engines, then Mr Goodwrench himself) and see if he remembers what a idiot light was set for. Maybe he has one some sending units laying around I could test. If I recall, the Chevy one is even the correct fitting size! I will call him, test, and let TDR know the results.

(next weekend I am taking the camper out, so it may be 2 weeks until I get to test. )

 

[TowPro]

I looked into this last night, and as far as we can remember, the oil pressure sending unit for a GM motor should turn on, or complete the circuit between 5 and 8 psi.

In 2 weeks I will buy one and test it with air to see what pressure it turns on at.

The question is will the sending unit hold up to diesel fuel?

 

[David_VT]

Yes, but can the VP44 prime the system on it's own

I think the main reason the transfer pump was kludged into these systems is only to prime the fuel pump.



My engine has seemed fine for a long time and when I changed my fuel filter only then did I discover my transfer pump was incapable of priming the filter anymore.



Clearly the VP44 has been doing all the work.

 

[redneckdr]

fuel pump

i put an aftermarket pump back by the tank, in series with the oem lift pump, at about 5k miles. gauges are next, and i will post the pressures with and without the pump. it'll be interesting to see if this setup lengthens the life of the oem pump.