Engine/Transmission (1998.5 - 2002) changed fuel filter, now no fuel flow

[WaltHess]

2001, 3500 ,HO, 210,000 miles, original lift pump.



Drove home last night, and was going to do a fuel filter change before leaving this morning, but it was raining---no garage. Went out this morning during a break in the weather,and the swap went fine until I went to start it up. It ran for a second then died. I bumped the ignition a few times, and I can hear the pump running (making noise), but no start. I popped the filter housing open,and it isn't filling up. I have cracked the lines from the pump, but that has not helped.



1--is the lift pump shot?



2-do I need to prime?



My concern is that I could possibly get it running by priming even though the lift pump is shot due to the VP44 having a pump too, and possibly causing damage to the VP44. But, I also don't want to spend $175 on a new lift pump if all it needs is a priming. I have changed the filter before, but this is the first time I have had a problem like this. The truck was running fine down the freeway, but I have noticed a loss of power when towing (3rd gear instead of 5th on some hills), and a decrease in fuel mileage (13-15 down to 9-10). No fuel gage yet, but on the to do list as the money from this side gig comes in.

 

[JLandry]

Walt,



You're going to need a fuel pressure test gauge to troubleshoot properly. That loss of power strongly suggests something is wrong... like low lift pump pressure or a damaged VP44 fuel injection pump. If you can't borrow one, you can buy an inexpensive fuel pressure test set from places like Harbor Freight Tools or eBay for about $25 or less. The only downside to these sets are that they typically come with a 100 psi gauge, while you're only interested in the 0-25 psi range. Using a 100 psi gauge won't be very accurate at the low pressures we deal with, but at least it'll give you a ball park indication... which is really all that matters for now. Whatever test kit you choose, make sure it will connect to a Schrader fitting... most will, except for the cheap vacuum/pressure type test gauges.



In the mean time, do the following in this order:

1. Close up the fuel filter housing.

2. Loosen the fuel inlet fitting located on the VP44 fuel injection pump.

3. Place a suitable container (or large wad of rags) under the VP44 fuel inlet fitting.

4. Bump the starter to activate the lift pump. Assuming the lift pump is working properly, this will force all of the air from the fuel filter housing and low-presure fuel line up to the VP44 fuel injection pump.

5. Tighten the VP44 fuel inlet fitting as soon as a steady stream of fuel gushes out. Note that once you activate the lift pump by bumping that starter, it won't shut off for the full 25 seconds even though you turn the ignition key off, so be prepared to tighten the VP44 fuel inlet fitting or at least catch all the fuel!​

Next, you really should test the fuel pressure by connecting a fuel pressure test gauge to the Schrader valve located at the VP44 fuel inlet fitting and then activating the lift pump by bumping the starter. Ideally you want to see a minimum of about 15 psi... a little more is better. Something like 5 psi without the engine even running is unacceptable and indicates a problem.



After verifying the fuel pressure with the engine off, you can try starting the engine by holding the accelerator pedal to the floor and cranking for 15 to 30 seconds. Allow the starter to cool for at least 2 minutes between attempts. Assuming adequate fuel pressure to the VP44, the engine should start on the first attempt. It may run rough at first until trapped air is forced from the fuel injection system. If it doesn't start, then you may need to purge air trapped in the high pressure fuel injection lines following the procedure IN THIS POST, except when attempting to start the engine, hold the accelerator pedal to the floor... several TDR members have found doing this helps tremendously.



Good luck and keep us posted.



John L.

 

[hsmith]

Your lift pump should have been replaced long ago. I have had on two occasions had the same problem. New filter and pump would not reprime. This was on VP units, not the one in my sig.

 

[WaltHess]

As far as I know the original lift pump was working fine until the last CA trip. Never had this problem before until this filter change. Guess I was lucky to have it last as long as it did.



I cannot take a pressure reading as there is no fuel flow at all out of the LP.



I am looking into F***** pumps since they are getting some good reviews here.