Engine/Transmission (1998.5 - 2002) F/P guage spike with VA

[Tcolesanti]

I try to post as little as possible due to the fact that almost everything that could or has gone wrong on these trucks has already been discussed. Here's my problem, I installed an Auto Meter electric fuel pressure guage, used an 18" grease gun hose and a high flow tapped banjo, coming off of the vp-44 itself. (I remote located the sending unit to avoid vibration). Everything was fine and dandy until I installed my Van Aaken box, all of a sudden I was getting more fuel pressure at idle (over 15psi) and when I would put it to the wood, the guage sort of jumps around and only goes down to 10-11psi. The truck has a brand new lift pump on it- replaced due to low fuel pressure, the original lift pump never died. I would like to figure this out soon and make sure nothing is seriously wrong.

 

[24V-DSL]

Couple of thoughts... .



Faulty sender? Corey at Autometer tech support is knowlegable and helpful. 815. 895. 8141.



On Corey's recommendation I bought a snubber, but I haven't installed it yet. Got it from Branom Instruments 503. 283. 2555. PN 12S-E. Cost was about 8 bucks. I think they're made by Chemiquip Products somewhere on the E. Coast.

 

[Tcolesanti]

The snubber you speak of, is that an inline fitting with a small orifice in the center to slow spikes from the injection pump??

 

[dresslered]

I have the same fuel pressure set-up as you except that I came off the outlet of the fuel filter. This is still monitoring the VP-44 inlet pressure, but you're another 18" away from the origin of those pulses. The OEM rubber hose between the filter and the VP-44 along with my grease hose seem to give me all the snubbing necessary. It's been great for 3-years identifying 2 faulty lift pumps along the way.

 

[Ken Roberts]

Fuel filter hookup

Can ya just screw the grease hose into the 1/8 pipe hole(after removing the plug) on the top of the fuel filter housing? Seems to be the easyist way.



KenR955

 

[Steve St.Laurent]

Ken, you probably have a 98 or 99. Your fittings are different than the later trucks. You don't even need a grease hose. All you need is an 1/8" NPT to barb fitting and fuel hose.

 

[Ken Roberts]

Fuel filter fitting

Steve, I have a 98. 5 24v All stock till today. Almost done with the gauge install. Autometer electric 0-100 fuel pressure. Yeah, I know, I know, but I bought it before I was a member of this group. I'll find a 0-15 soon enough.

There are 2 plugs on the fuel filter cap. I just assumed that I could put the sending unit into one of them,but it seems like others are using a grease gun whip hose to control vibration and pressure spikes.



KenR955

 

[Steve St.Laurent]

You definately don't want to install the sending unit directly to the filter head because of the amount of vibration from the engine. But you don't need to use a grease hose either. Most of the guys talking about grease hose have 00+ trucks which have a shraeder valve for checking fuel pressure. Their filter head are different than ours and don't have the test ports ours do. You can see how I installed mine here - https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=6113 . Mine is a 98. 5 too. I installed mine 4 years and 115,000 miles ago with no problems since.

 

[Tcolesanti]

I moved my tapped bango bolt from the vp 44 inlet to the outlet of the fuel filter housing. And with the 18 inch grease gun hose, calmed the spikes down. thanks dresslered

 

[TMinistro]

Hey guys i had the same problem for months. My mechanic said he was trying something new on another truck to just wait. So i did he put 100 fuel pressure gauge on a truck still didn't work. Then he told me about the snubber i was doughtful but it worked for about 2 weeks no problem. The cost was only 8 dollars.

 

[Ken Roberts]

TDR Help

Steve,

Thanks for the help. I will be installing the line today if the rain ever stops falling.



Ken R

 

[Ken Roberts]

Good news. The gauges are installed. The bad news is that unloaded I have 8 1/2 psi at idle and 1 1/2 - 2 psi at WFO.

Boo Hiss!!! Lift pump time! I assume that when I am pulling the trailer(7000lbs)fuel psi will drop further.

The turbo was showing 15lbs of boost. I assume that will rise to about 20something when towing.

Are lift pumps covered with the 100K mile warranty? I believe only the VP44 has that warranty.

 

[dresslered]

Lift pumps are covered under the 100k warranty as well. The tough part will be getting the dealer to admit that it is bad. My local dealer (skull and crossbones over at Dave Fritz' site) didn't even realize that my truck was a diesel, so I replace the lift pumps myself. Both times I sent DC the bill for the parts and delivery and they have sent me a full reimbursement check.

 

[T Smith]

desslered:



When you send the information to DC, what do you tell them and where (address) do you send the info?



I've had to do a few warrantable items myself due to my location. It would be nice to at least be reimbursed for the parts.



Thanks,



T Smith

 

[BT]

I have an SPA gauge with a hose down to the schraeder valve off the VP-44. Stock engine with no funny business. The gauge was working great for about 6 mos but then started fluctuating all over the place. Posted some time back on this problem. Changed sensor, worked for a while but problem came back. Long story but turns out air was getting in the line.



I installed a 3-way valve set up so I could bleed the line. Problem immediately went away. It periodically starts fluctuating again; I open a needle valve with the engine off, and problem goes away. It may be that there is enough entrained air in the fuel that it builds up over time until there is enough to compress in the fuel sender line, and it starts pulsing with the variation in lift pump output as fuel flow varies under acceleration/deceleration. Argues for the FASS system - to remove the entrained air in the fuel?



The 3-way valve system works great for changing the filter - I put the new filter in dry, open the valve and bump the starter a few times. I have a piece of tygon tubing attached to the valve outlet and can see the fuel come out when the filter housing is purged. Starts up no problem

 

[Ken Roberts]

Installed lift pump. 14lbs at idle and 9 at WFO. I expected more. I have 1 psi drop across the the fuel filter. What gives? I bought the pump at a Cummins dealer cause the Dodge dealer was still playing screwaround with warranty.



PSI should be about 11lbs at WFO, right?



KenR955

 

[Tcolesanti]

My rule of thumb is if it drops below 6psi (WFO) then change the lift pump but 9psi is fine-IMHO.

 

[Ken Roberts]

lift pump again

Well,well,well. The pump have been installed for appx 3 months. I had pressures of 14-15 idle, 11-12 normal running and 9-10 WFO pulling 7K trailer.

The last week I have seen weird stuff happen. PSI at idle will be 15, drop to 9 up to 12,down to 4, up to 9 then to 15. over and over again. all within 90 seconds.

then yesterday idle stayed about 4-5psi,unloaded running 75-85mph was

6-7psi and WFO was 9-10psi. This I don't understand. I realize I need another lift pump, but more psi at wfo that at idle?

Anybody know why?

I have both pre and post filter pressure and they both show the same psi.



Ken R



98. 5 stock except for gauges

 

[Tcolesanti]

Your lift pump is goin south. My last lift pump (I like the way that sounds) started getting erratic at about three months old and I checked everything. Electrical connection, fuel filter, tank pickup, came up with nothing. I don't exactly know why they do this but a good number of lift pumps get erratic right before they crap out. I heard the diodes inside the electric motor get hot enough over time they disintegrate. Maybe they are causing the pump to cavitate???