scook6

First off let me thank all of you who have posted info on this site about CTDs. I have learned more reading on this site over the last four years, it is truly amazing the knowledge base here and I have learned so much. I bought my third sec. gen. truck new in 2002 but it was my first diesel. I will never own a gasser again. Now on to the business at hand. Now that my truck is no longer under warranty I have been playing around with the lift pump issues. Mine has the intank pump and I decided to put back in place the pump up on the engine. I have a fp gage 0-15 psi looks as if I am going to have to upgrade to a 30 psi unit. I have my system set up so I can start with the tank pump, then after the grid heater begins to quit cycling I flip a switch and turn on the other pump. The pressure pegs the gage. So I really am not sure what the pressure really is but after much reading on here most likely about 22 psi giving the fact that the new pump is about 15 and the intank is giving me 7 psi. My question is this: Is this too much pressure? If so where can I get a reasonably priced fuel regulator and at what pressure should it be set at? Again my many thanks to all of you and Merry Christmas.

dieselfan

22psi is fine, i run 24-25psi with no problems. i think when you get close to 30+psi is where you could run into trouble.
i ve seen some people run regulators, but i just don't think they are needed JMO.
good luck in whatever you choose to do.

dieselfan

tenbrooks

Run a 1/4" bypass to the return line if over 22psi, no need for a regulator

piperca

The pressure issue seems to be truck specific. Some trucks can run upwards of 20psi and have not problems, others don't quite reach 18psi before they develop hard starting issues. I was running mine at 22psi and noticed a hard start problem. Another Cummins owner I know got the hard start at 18psi.

There is really no reason to run those kind of pressures with the Walbro, since it's volume you're looking for ... 70gph @ 15psi is plenty! Also, I've heard that on some high mileage VP44 units the seals don't like the added pressure.

I'm running 18psi and don't see anything below 16psi and that's with a Simflo regulator from AFS.

high country

my truck ran 30+lbs for at least 50k miles. My pump puked due to failed electronics. I did once lose the seal between the vp and crankcase which could have been from too much pressure or just random. the bosch guys think it was random as the seal I poped was viton over steel. I never once had a hard start problem but I have my pusher triggered from the stock pump via relay so start up pressure is about like stock. fwiw I am running a 7lb carter pusher on the frame and the stock engine mounted lift pump, which by my math should have been good for 19-22lbs but instead never comes off the 30lb mark, rarely even on a 5x5 pull.

hope that info helps ya.

scook6

Thanks for you help. I am wondering, where is the best place to tie the bypass line in at? I noticed that between the fuel filter and the IP there is about a 3in or so rubber line. Would it be okay to put my tee there or is another place better? Thanks

piperca

I'd recommend puting in some sort of regulator and running a line back to the fuel tank vent. If you do the bypass, you're stuck with whatever pressure you get and you're not always guaranteed that the result will be acceptable. I've also noticed that trucks that use the bypass method lose an extreme amount of pressure under WOT. Yeah, your running 25psi at idle but dropping to 11 or 12psi at WOT doesn't make sense. In my opinion, controlling that drop should be a concern.

With my AFS (Walbro) setup, I don't see any more than 2psi of a fluctuation between idle and WOT. Even at cruise, the fuel pressure recovers to 17psi. I can send you some pics of my install if you'd like?

team

I had hard start problems with 15-20 psi when i went to my walbro set up. I got an ecm reflash that fixed this but I also lowered the pressure. No use to run loads of pressure (creating a restriction that cuts down fuel volume). I keep it about about 10 psi. Check out the flow charts on the glacier diesel website. Pressure goes up and flow goes down.

http://www.glacierdieselpower.com/pr...?pf_id=3929852

http://www.glacierdieselpower.com/pr...1148017926.JPG

Ranman

I have been using the Glacier set up for 4 months now and have pulled one of the thin washers out of the regulator to drop the pressure to 15. I have a 0-15 psi gauge and didn't want the needle pegged all the time. I also think as long as your getting good flow 15 is no problem. Hey works great. My gauge will bounce and I have starting issues when I'm at 1/8 of tank. I think the walbro pump will suck a tank lift unit dry fairly easily and cause this when the tank is low. So when it hits a 1/4 I start looking for a station. Wish they baffled the tanks and not relied on the sending unit.

dsl kicks gas

if your gettin 30psi out of a 7psi pump and a stock pump(15psi) would would 2 stock(campagin) pumps run at? im goin to put a pusher pump on the frame rail saturday and i was woundering if i need a bypass or regularor.


i have a 16psi guage, so i know i'll have to get a new gague.

scook6

If I was to put a regulator on my truck any ideas as to where and what kind to get? Looking in various places on the internet all I seem to find are 4 to 9 psi regulators. Also where is the best place to plumb this in at?






2002 2500 Q/C SB 4X4 Atlantic Blue Silver

piperca

A Mallory 4307M will give you 4-25psi and can be had for around $80.

The best place to install the regulator is right before the VP. This will allow you to see constant pressure. Most are plumbing it in right after the pump and are seeing pressure drops under throttle, but that's normal for our setup. The benefit of this setup is that you don't have to run a bypass line from the engine bay.