[quote author=Cumminsdieselboy link=board=4;threadid=19177;start=0#msg180672 date=1062716741]
I have a PE 4200 and have the same problem. it is hooked up to the stock wireharness. will it work if we have a switch too and not turn it on until the engine is on instead of having it 20psi. I hope this will work.
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I think your problem is that the PE has too much flow to be able to bring the pressure down to startup specs for the VP44

One possibility would be to use the run/acc hot wire for the radio- downside is that the pump would run with the key on ACC, which could lead to problems, but could also help imn bleeding air out of the system.
Another possibility should be the wire A22 going into the junction block to C9 (14GA BK/OR) that should only be hot when the ignition is on. (Taken from a 99 service manual, please verify that this is correct for your truck before splicing anything, I am not responsible for any kind of result!)

HTH
AlpineRAM

 

I've got the pump wired to a switch. It works great!!! I turn the key on, turn the switch on for a second, turn it off, start the truck, turn the pump on. I've actually got enough of a prime in the line's before starting without turning the pump on, but I do it anyways. There's no more hard starting or anything. I took the truck on an 1.5 hour trip running 80mph, got home, shut it down, fired it right back up with no problems. Now, if I could only stop this fuel leak I'll be set.

 

BB, I wrote this to answer to CTDboy. He has the same hard start as you, and seems concerned about forgetting the switch.

Glad to hear that your VP44 is OK, must be some relief for the piggy bank ;D
Where do you have your fuel leak ? I've got a massive fuel leak in the exhaust pipe

AlpineRAM

 

I wish I had that fuel leak Alpine. This one is at the fitting that goes into the pump. It only leaks when the truck is shut off. I've got plumber's putty all around it and it still leaks. I've got to order a new fitting but don't have the money right now. It's not a bad leak, just kind of annoying.

 

On the fitting that goes into the inj. pump?
I'm shure you tried retightening. Have you tried to remove, clean, look for burrs and reassembling?

AlpineRAM

 

No. The fitting that goes into the lift pump. It is a 45* elbow and is leaking at the point that it connects to the female end of the fitting. Look at the attached pic and you'll see. It's kind of hard to tell someone.

 

Alpine, it would not be too hard to put a wirewound resister in line to slow it down and an oil pressure sender kicking a relay to put it to full output. What you think?

 

HID: I don't think that regulating the speed of the pump with a resistor is generally OK. Some pumps don't like being operated at lower voltages under high pressure. The internal bypass is needed for cooling purposes in many pumps. So if you'd put in some resistor you'd operate the pump at a significant torque on the motor and without cooling. I think that you'd have to ask the supplier of the pump whether they will support electrically regulated operation or not.
Actually it would be nice to regulate FP with a sensor on the banjo that goes into the VP44 and a pump in the frame rail.
Also the relais would be operating very much to hod a pressure that's between max pressure and the pressure that's available with the resistor on.

BB: have you contacted the vendor ? Looks like something is wrong within the fitting.

AlpineRAM

 

[quote author=AlpineRAM link=board=4;threadid=19177;start=15#msg182337 date=1063085134]
HID: I don't think that regulating the speed of the pump with a resistor is generally OK. Some pumps don't like being operated at lower voltages under high pressure. The internal bypass is needed for cooling purposes in many pumps. So if you'd put in some resistor you'd operate the pump at a significant torque on the motor and without cooling. I think that you'd have to ask the supplier of the pump whether they will support electrically regulated operation or not.
Actually it would be nice to regulate FP with a sensor on the banjo that goes into the VP44 and a pump in the frame rail.
Also the relais would be operating very much to hod a pressure that's between max pressure and the pressure that's available with the resistor on.

BB: have you contacted the vendor ? Looks like something is wrong within the fitting.

AlpineRAM
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You are probably right, what I had in mind was just the reduction while starting, as soon as oil pressure hit the sender the relay would connect it direct. If I'm not mistaken, that is somewhat like what the ECM does on the stock pump, except that it also times it out.

 

OOpsie... I had gotten you wrong. I thought you wanted to make a regulator that would always give you, say 16psi, at the VP44, without overpressure at low load. Well, that would be viable. But to keep the stuff simple you could also take a wire that's hot only with the key to on and use this to make the pump turn under load and a solenoid valve to bleed off pressure while cranking. In my experience the truck will start readily without fuel presssure as long as there is no air in the system. I rigged up a capacitor and a resistor on my LP trigger relay to have the pump off while cranking and on when the ECM commands full power. Starts easily, runs good, costs almost nothing.
I think that there is a misconception about LP pressure:
We do not want pressure, we want a guarantee that the VP44's elements are filled in time. So we are talking about flow here, not pressure. Since we can't reasonably measure flow in the VP44 we must rely on pressure on the inlet and assume that this pressure means sufficient flow.
We shall need the flow under load, and very little flow under no load. The timing of the VP44 is regulated by pressure that is bled off with a duty cycle solenoid. The pressure is generated within the VP44, if we push in much more pressure than intended we will get a timing error. (and a hard start condition due to the timing being way off and the VP44 unable to compensate). So what we'd really need is a system that would regulate fuel pressure according to rpm and load. The higher the first two, the higher the latter.
Hereby we could assure that there is enough flow when we rev it up and stick the foot in the firewall, and in case we don't do this we don't force the VP44 to swallow presure.

Just my 2c

AlpineRAM

 

I wondered how that worked, good info. Reason that I came up with that deal is that two system that I have used for other systems in the past are oil pressure sensors kicking a relay, and altinator juice ahead of a diode on the charge line to provide a positive voltage only when the engine is running. Guess I am probably designing a watch instead of telling the time Blue had expressed a belief that his trigger wire from the ECM was bad and I was just sort of thinking of a way of duplicating that system. All theory from an overworked and tired mind :-*

 

I think that your theory is good, or maybe even better than the stock system that uses duty cycling to lower FP during cranking. My experience and BBs results show that you can easily start on 0psi FP if the system is properly primed. The proper priming should be achieved by the first 10 sec run cycle when turning the key to "on" in stock mode. Then, during crank the LP is cycled on-off--on etc.This will be seen as low er FP while cranking.(Inertia of the instrument)
For BBs stuff it should be feasible to hook up the relay trigger to a wire that is hot with the key to "on" only and therefore deactivating the LP at startup. If the system had lost prime and the engine wouldn't fire, the operator would stop cranking, the LP would come on again and reprime the system. The only downside I see is that if you let the truck stand with the key "on" the LP would run all the time. (Potential hazard after an accident, potential drain of batteries)

AlpineRAM

 

Alpine and Blue, really I think this subject has been overworked but I will relate a situation that I had and it does have a caution in it to take note of. In the '80s I had a big truck with dual tanks. The pull tank was on the drivers side. At one point I had to pull off on the shoulder and shut down. Common practice with big trucks was a transfer line from the bottom of one tank to the other. The fuel shifted to the passenger tank and I lost the prime, took me a couple of hours to get going in the rain. A CAT can be nasty to prime. Later I pulled the transfer line and installed a carter race pump that I had for my 440 GTX to transfer the fuel to the pull tank. On an inspection I was shut down because there was no accident safety feature, ruined that day also. I had a battery isolator on the truck to run ham radios from a second set of batteries, so I just took the feed line for the pump and connected it to the altinator output, satisfied the inspectors as it had no juice until the engine was running. Somewhere buried in fedeal law there is a restriction on running a fuel system with no emergency shutoff that is automatic. Cars here have an impact switch, the ECM does that for our trucks.

 

i dont have a PE, but my pusher pump is wired to a switch in my cab...i start the truck off the LP then turn on the pusher so the FP isnt high for start-up...only prob is, gotta remember to shut it off..