James Andres

Changed the fuel filter again on my 99 with 65,000 miles. I only have a small gauge on the top of the housing so I am unsure of any prior problems. (idel at 11 pounds was normal)Bumped the starter and the pump ran but built no pressure. After 6 tries still nothing. Filled the canistor with fuel and still no pressure. (Checked gauge o.k.) Cranked lots and opened 2 lines to get it running. O.K. now when bumped it's delievering 11 pounds and O.K. at idel. Shut down and try again... 0 pressure.. What? Did this about 10 times and sometimes it would deliever pressue and sometimes nothing. I could always hear it running but it changed in pitch. When it did work it would stay even after the truck was started. It would pull down to 7 under hard excelleration. When it failed it stayed that way until I shutdown and restarted. Dealer confirmed and replaced liftpump under warranty. <br>WARNING TO OTHERS!!! Just because a temporary gauge shows you as o.k. on a few runs doesn't mean the liftpump is working every time. My temporary gauge is taped in place until I can complete a permanent install.

StakeMan

A fuel pressure gauge is the 2nd most important gauge.

admin

James, thanks for the information. I think I'm going to replace my pump as a precaution. I don't like the fact that it sometimes goes down to 7-8 psi wot. I would rather see 10 if possible. I also have a feeling that sometimes it's not pumping correctly, either that or my Injection pump is going bad. <br><br>Although the weird thing is that since the weather became cooler, I haven't had my hard starting when warm problem NEARLY as much as before.

admin

I also have the Briar Hopper gauge and I attach it about once a month for two or three trips. I think I need a permanent gauge.

StakeMan

I have a Dakota Digital fuel pressure gauge that I stuck in the ash tray. With a new lift pump I see 16 psi@idle 12-13@cruise 3.4@WOT with the box set on KILL. Its time to get a pusher pump.<br><br>I highly recomend that any 24 valve truck should have a permanant fuel pressure gauge. The temporary gauges are nice, but you can't watch the fuel pressure trend. Over time I expect to see the perfomance of my lift pump degrade.<br>

admin

3.4??!?!?! Geez. I have never gone below 7 with mine, but I only have a comp with no pump wire attached at the moment. I want to get all fueling issues resolved before going further with the comp

StakeMan

Comp + injectors = ;D = low fuel pressure

admin

ahhh, yes, I see

latitud_rt

I keep reading about lift pump pressures getting lower and lower. I also read people talking about the fuel delivery line is too small. Is it possible to replace the delivery line with a larger ID? I only have 1800 miles on my 2002, but I am going to install a permanent fuel pressure gauge, probably the Dakota digital. Where should I mount the sender?<br><br>Thanks

StakeMan

I have mine remote mounted pre-filter. I am going to mount it on the bottom of the filter housing which is post-filter.

BigBlue

You think 3.4 is low? I could pull mine to 0.0 WITHOUT the Comp on. It idled at 8 or so psi. With my new pump, I am now up to 6.4 @ WOT (Comp on. 8.0 comp off), 10.8 at 70, and 12.0 at idle. Idle used to be 13.4-13.6. Just got the thing 200 or so miles ago and already losing pressure. Those pressures are WITH the bolts from Geno's and a new filter that hs 30 miles on it. Talk about a crappy pump. I need a pusher but I don't want to have to fight with the dealer again on aftermarket parts and crap like that (I know. I'm going to have to take the bolts back off but I just thought I would give it a try.)

chuck3

Blue the dealer most likely dumped one of the old leftover pumps on you. See if you can see the part # on it.<br> The good pump from Cummins is # 3990105. <br> I have had no problems with my new one 16 psi idle and I have never seen it go below 12, even at WOT with comp on.

BigBlue

I'll check Chuck. Wouldn't surprise me if they did. After all, I did stand up against them when they tried to void my warranty. They probably didn't like me doing that. Oh well. If it craps out within the next 1000 miles or so, I'm installing my own and I'm putting it back by the tank where it should be.

My gauge is hooked up at the port on the injection pump. The port farthest from the filter housing with the black plastic cap on it.

TPilaske

OK... is my lift pump gold? I have my gauge pre-filter. Normally I would see 15-16 at idle, 13-14 cruising, never dropped below like 10 when flooring it. Now it's 16-17 at idle, and has gone up to 18.4 -- usually never drops below 14-15 cruising, and when accelerating to get on the E-way only drops to about 12.4 and then jumps back up to about 14ish... So is it the holy grail of lift pumps? Or my brand spankin' new dakota digital sensor going haywire? ??? ;D

Tony

Ooops - forgot to mention, I did swap all the banjos w/ high flows when I put in the gauge. It has been in for a couple weeks now, but just the past couple days I started getting the higher readings!