Engine/Transmission (1998.5 - 2002) Need a LP guage

[Houser]

Houser Here

So like after replacing my LP and Injection pump I have decided Yea you diesel heads are right, I should get a fuel pressure guage installed on my LP. I suppose I should do the EGTs while I'm at it.

Any suggestions on a good set up.



Thanks

Houser

 

[JPLB22]

If I may ask, How many miles did you have on it at the time of injection pump replacement ?? And did you have any fuel mods ?? I am curious cause I also have an '02.



There are a few recomendations I would make. First is, when you do decide on what gauge you are gonna use, to take your pressure reading from the inlet to the VP44. With you having an '02 you should have a schrader valve right at that point. There are some people who make temperary gauges to mount to the schrader. Or for a full time gauge you can decore the schrader and you now have a female 1/8 npt fitting. IMHO taking the reading from the inlet to the VP44 is the safest and most accurate. If you only have a prefilter gauge you will not know what is truely getting to the VP44.



Second is to upgrade the stock fuel delivery system. The banjo's that the system runs through are very restrictive ( which hurts your flow to the VP44 and shortens the life of the LP ). There are many many ways to do this. My personal choice was the Wildcat Max Flow Kit. It removes the entire line system from the stock hard line under the truck, all the way to the VP44. It is replaced with rubber and S. S. braided line and some very nice high flow fittings. There is also the F. A. S. S. system. And I'm sure there are some more to add...



Jeff



P. S. I am not affiliated with Wildcat Diesel, just am a happy customer .

 

[lcoblentz]

You're gonna get all sorts of answers about which gauge to install. Bottom line, any gauge is better than no gauge at all. I would recommend the following general guidelines: Mount the probe for EGT pre turbo (in the exhaust manifold). Use a mechanical gauge for fuel pressure, and don't forget to add the snubber valve (do a search on this one, there's lots of good information) Also, many companies, like Wildcat Diesel, offer packages for gauge installation that will include all the required parts.

 

[JPLB22]

You should be careful when using a valve for a snubber on a mechanical fuel pressure gauge.



I run my mechanical gauge with no isolater. Just straight diesel to the back of the gauge. I feel this is the most accurate way to do it. But, that accuracy comes at a price. The VP44 causes vibrations in the fuel that make the gauge rattle and buzz like crazy ( more than enough to make me want to drive right off a cliff ). So someone came up with the idea to use a needle valve as a snubber to lessen the vibration between the VP44 and the gauge. Common practice is to close the valve completely and then just crack it open ( 1/8 of a turn or so ). I used that method for about 7 mo.



Then I start to see my LP pressure start to fall accross the board, idle - cruise - WOT, where all falling. So I go and buy a new LP from Freightliner for $133 + tax, and order a Wildcat Flow Kit. I install my new goodies and hook up the gauge as I had it before. Everything is great ffor about 2 weeks, then my pressures start to fall again. I'm thinking great, must have got a junker LP right out of the box.



The problem turned out to be the needle valve. It was giving me false low readings at the gauge. Even with it open 3 full turns I was only reading 8 psi at WOT ( with the gauge buzzing like there was no tomorrow ). Also noticed that my pre-start prime pressure was off also. But here is the killer, my cruise psi never changed. The false readings where only coming during WOT and pre-start prime. So I removed the needle valve completely, and now my WOT = 11 psi and prime psi is back to spiking to 15 psi before start. I also slightly modified the Max Flow Kit so that I now have no needle valve and no buzzing of gauge.



Sorry for runnin on, just sharing my experience.



Jeff

 

[Houser]

JPLB22



Thanks for the input. To answer your question, My pump Began failing @ about 41K I got the 216 Error code around 38K.



Houser