AlpineRAM

Well, I do not recommend crashing it.
If all the standard stuff works as you say you should be OK.
I do just prefer to do it the way I said because I work on many different vehicles and this way is basically easier and less risky. (EG Volvo turns on the DEF pump plus when you turn on the key, and does the dosing by doing PWM on the minus side. If you would do it your way you would empty the DEF tank into the exhaust in 15 minutes, and you'd need a new SCR Cat- about 12k US$)

robert78.5

I cant believe it, started truck this morning,. I did the starter bump to see if pump was working, it ran its 20 seconds at 12 lbs pressure, waited for start light to go out and fired it up, idling with 12 lbs, went into house for 10 minutes and came out, truck was still running but was at zero pressure. I shut it off and hit the bump stater again and pressure went to 12 for 20 seconds, i hit starter and engine started with 12 lbs at idle for about one minute than slowly started to lose pressure , i hooked volt meter to power wire going to transfer pump and had 12.4 volts, i watched pressure drop to zero and pump still had 12.4 volts and was still pumping.. could the screen in fuel tank be that plugged to restrict fuel flow? I have never had tank off and have 660000 kms on it now. ,, i changed inline filter before electric pump and factory fuel filter 2 months ago. ,, maybe time to retire truck. or could bypass fitting on vp44 not be holding pressure anymore?

AlpineRAM

The bypass fitting has a spring and ball- so it either works or not.
I think you should investigate :
A: The pump itself- check Ampere draw when it fails, check flow
B: Check the suction part to the pump- leaks and blockages

At 660 000 kms the engine is barely broken in. No need to retire the truck. Find the root cause for the problem and get a functional truck for less than 1% of the price of a new truck.
(And invite the lady of the house to a nice dinner to round it up to just several 10 000 $ of savings)

high bid

Robert... you replied on the other thread "fuel psi and fuel gauge" in reference to low fuel psi.
I have almost the same issue. What lift pump are you running?... is it the Airtex?
After doing....
With the current low fuel psi, I've installed/cleaned;
1. new lift pump- the second one and have had all the low fuel psi issues as noted prior
2. dropped the factory fuel tank, cleaned it and the fuel sender housing and fuel lines -not that much debris
3. blew out the fuel line from the vp44 pump all the way back to the tank -nothing found
4. changed the spin-on fuel filter 2x and changed the factory filter 2x - the second swap there wasn't much debris in the pre-spin on filter and the factory one looked clean
Going to check the voltage to the pump, connections and go from there.....

robert78.5

i am using the carter orignal style for now. was thinking of blowing fuel line back into tank and installing a new inline filter, ,

AlpineRAM

I'd strongly recommend to check for air in the fuel too.
Any pinhole that lets in air at the suction side will not show as a fuel leak but it will damage lift pumps and injection pumps.

high bid

Good point... I'm going to go back and check all the hose connections and clamps making sure good and tight so as to not allow any air into the fuel line.
I removed the extended wire harness (about 1') which was for the lift pump to eliminate any potential connection issues and confirmed 13.5V to the lift pump.

AlpineRAM

You can use a bit of clear hose and connect the fuel filter drain to the filler neck.
Start engine and slowly open filter drain- fuel without bubbles should flow to the tank.

high bid

Appreciate the input...... Checked and tightened all hose clamp fittings. One thing I noted;
When starter bumped to run the lift pump (engine off) fuel psi goes to 14, then when engine started, fuel psi drops to 9 and then in park when pushing the pedal fuel psi drops to 4-5psi.
To me, this says bad lift pump as it can't keep up with fuel delivery to the VP44 BUT this is a new lift pump.
Thoughts?

Driving it, the truck threw a code and tach bouncing from zero.....

AlpineRAM

OK, either the pump is bad, or you have a restriction to the flow.
You will need to determine where the restriction is.
You can use the method with the clear plastic tube I mentioned to determine flow- just put end of hose into 5gal canister, open drain, bump starter and use stopwatch and scale to determine flow rate.
If too low, remove pump, supply external power supply and let it pump from your 5gal canister into the tank - much faster=pump OK, restriction in the line.

high bid

Airtex E7153 lift pump test;
Ran a (+) and - lead to the lift pump, started ran the fuel psi up to 14.5
Ran a clear hose from the fuel canister drain to a 2gal red plastic gas can.
Using a stop watch I ran the test twice; pumped for 1min of which less than 1gal (72oz) flowed. (128oz = 1gallon)
Using a stop watch I rant the test twice again; this time, I pumped for 2min of which less than 1gal still flowed.
There was very few air bubbles flowing at all for all four test.
The pump max free flow rate is 55gph
At this point, I'm convinced that the new Airtex E7153 pump was junk/bad out of the box as it will not even flow 1gal/min.

AlpineRAM

OK, either your pump is bad, or you have a restriction somewhere.
Main suspect would be on the suction side, so I would repeat the test pumping through a bit of hose from one gas can to another.
Significantly faster= suction restriction or output restriction.
No difference = dud pump.
Big difference, close to 1 gallon per minute flow, other problem.
To verify suction or output restriction- test input from gas can through fuel filter as already tested, flow significantly higher = suction restriction.
Flow still low, output restriction.

These tests should be done without the engine running and with a battery charger.
With the engine running and just letting fuel out of the water drain you can not estimate the pump flow because the VP44 will suck a lot of fuel through it's internal vane pump. (Remember it was developed for a naturally aspirated 2.4l 6 cylinder diesel and used without a lift pump there)

With your test (engine running) even a few air bubbles are too much- you are on a port used to drain water (lowest point in the fuel filtration) and are checking for air.
I assume you'll see much more air at the same test with the engine off, and your poor VP44 is running on a lot of air and a little fuel.

robert78.5

Dumb question,,,, will a plunger style mechanical transfer pump work from a 1997 on a 2001 engine?

AlpineRAM

Not really easy- you need the boss for the pump on the block, a camshaft with a cam for it (24V cams don't have the pump cam AFAIK), and a pressure regulator with enough capacity to keep pressures in check.

robert78.5

I installed a new Carter pump from NAPA, in original location on engine, blew back fuel into tank and retightened all hose clamps, the hose between the pump outlet and the final filter on engine had a bit of a buckle to it. I installed a new hose and all new crush washers. Just took it for a 20 km trip and all went well, Pressure stayed up and did not go much below 9 psi when i acceclerated hard to 120 kmh. I think i will put pump back of frame by fuel tank next summer when weather is warmer. I am not pulling any trailers this winter so shoud be good. Thanks for all the tips. PS i left the relay between battery and pump..