Engine/Transmission (1998.5 - 2002) lift pump thanks/tst question

[2broke2smoke]

first off thanks to all the folks on here that said get a fuel pressure gauge ... . second thanks to all the folks that said take off the filter housing and go in through the top ... just did mine and took all of 30 minutes ... now for 2 technical questions, first; shop manual says that vp has an overflow valve that opens at 14 psi, how can i be seeing more than 14psi on new westach gauge? (smaller orifice?) please be technical, i can keep up and second; with new pump and rods max flow kit i plan on getting a box after hearing opinions... was gonna go with tst 3 adjustable ... please be frank ... if i'm gonna drop almost $700 i want the best and don't want to have to redo (respend) anything, in the next six months will be getting mach 3s and a turbo ... gonna study things on here a while first ... if any turbo manufacturers want to test a new ballbearing turbo please contact meOo. ... o yeah i have a transgo shiftkit in as well

 

[Hohn]

Answers for you...

Yes, there is a bypass on the VP that opens at 14psi. This is to protect the internals from high pressure, which causes hard starting and other bad things. There are two reasons you can see more than 14psi with your gauge:



First, your guage measure what fuel pressure is wherever it's tapped into, NOT inside the vp44. My truck idles at 17psi. But this is measured BEFORE the restriction of the VP44 inlet. After that restriction, you would have lower fuel pressure.



Second, the lift pump is capable of pumping more fuel to the engine than it can suck through the restrictive banjos. So, like I mentioned above, the pressure drops to below 14psi by the time you get past all the banjo restrictions. Thus, the bypass of the VP is closed.



Now, if you upgrade to the MAXFLOW kit from Wildcat, there's a good chance where you might actually be getting more than 14psi at the bypass valve, and it would then open.



I would expect the installation of the fuel line kit to keep your fuel pressures closer to 14, both above that number and below it. Your idle fp might go down, but your cruise and WOT psi should be higher than before.

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As for fueling boxes, the TST powermax COMPETITION model is the way to go. You won't have to buy another fueling box later. The TST boxes are tamer on the timing, so while they MAY run a little hotter, you WANT that tamer timing when you talk about WOT and keeping the headgasket alive. Installing larger injectors will give you even more timing, so I would recommend that you not get too happy on timing if you plan on running stage 3 or better injectors.



Moreover, the TST box is capable of fueling as heavy as any box on the market-- period. There are some that can come close, but none can surpass it. It can deliver wicked fueling levels. The 10 levels make it a little more adjustable than some others.



Second, the TST box is cheap. You can buy it AND the adjustable remote for only $700. Other "drag" or "competition" boxes are much more expensive.



Third, they are stone axe reliable. You RARELY hear of a TST box going out.



If you HAVE to have timing in your box, I would suggest the Diesel Dynamics version of the Edge Comp (the DD Universal Fueling Module DDUFM). I would NOT recommend the Edge Comp, since it's too aggressive on the timing when combined with larger injectors. It's borderline even with stock injectors.



The edge Comp is probably the most popular box here on the TDR by quite a margin. Lots of guys love it. I personally think you can do better. One nice about the EDGE boxes is that you can adjust the aggressiveness of the fueling curve on the bottom separately from the rest of the curve. This lets you keep smoke down a bit. The TST does not allow independent adjustment. In order to reduce low end smoke with the TST, you have to turn the whole box down.



Also, the boxes work a little differently. The TST determines fueling based on boost level. The Edge-style boxes determine fueling based on pedal position and other variable.



As a result, the TST usually shows more power on a load dyno, the Edge boxes usually show more power on an intertial dyno.



It's probably a wash as far as peak power goes, but the TST in competition form has no equal for bottom end fueling. It's truly wicked. Find the guys who have them and ask them.



Me, I only have the EZ. It's fine for now, but I will be leaving the Edge bandwagon when I upgrade to a fueling box. .



Justin

 

[2broke2smoke]

thanks, exactly the type of info i was looking for ... have been browsing the sight for about 6 weeks and wasn't sure if it would be worth the $ to join, now i see that it's money well spent, btw i have it tapped at the gap in the hard lines between the filter and vp, temporary untill wildcat max flow shows up from backorder, as soon as i have the big lines in i'm gonna get the tst ... again thanks for the reply

 

[JNeiman]

I have a powermax 3 in my 3500 and on the highest level that truck aboslutely rips. BUT, a trans-go shift kit will not hold all that power, and especially if you add injectors and a turbo. You need an upgraded automatic... search DTT, ATS, Suncoast, BD, these are probably the best out there, but the transmission is a must for that kind of power. The Powermax is highly recomended though!

 

[Six_Man_Diesel]

Dude, you won't be respending anything after you buy a TST PM3, only thing you'll be spending is money on your trans. My truck has 60,000 on it, stock clutch will not hold in 3-5 gears when PM is on 9. You will have a smile on your face.

 

[2broke2smoke]

that's what i was hopin' to hear ... the sooner i break the transmission the soon i get a DTT

 

[Hemiless]

here's a good post

2boke2smoke,



Here is a good post on fuel lines, lift pumps, pressure and flow trends within our trucks fuel system. Enjoy reading all eight pages of post I know I did.



pumps,lines and whatnot post

 

[2broke2smoke]

great post hemiless, kept me up an hour past my bed time, i'm gonna put on the wildcat flow kit and keep an eye on the fp gauge for the time being ... . the amount of thought in that post was amazing ... . glad to see that it's not just me