Good stuff. I'll post up here tomorrow and let you guys know how it came out.

Please, I request, pray to the diety of your particular denomination for my successful repair, tomorrow.

Mike.

 

You may be on to something , I think that the Valve you speak of has Plastic Washers IN stock form and when the pumps are rebuilt they put brass washers in there ...hints the reduced failure rate of remaned pumps

 

Well I sure hope so. All I know is that I don't have any signs of the VP going out other than hard starts; and hard starts could be cause by all kinds of stuff. Also, I noticed that when I bump the starter and let the LP run for a while, it seems to take less effort to start - still have to crank it a bit, but less effort.

Seems to me that if I can push this little ball thingie in the valve down just by touching it, then it sure ain't regulating to 14 psi. If thats the case, logic dictates that (as long as the check valve in the LP is ok - which is questionable at this point) the vast majority if not all of the fuel is leaking back to the tank and isn't in the VP possibly, hopefully, causing my hard starts. That's just my logic but I'm praying for the best.

Mike.

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Well folks, I'm sorry to report that the check valve didn't make a darn bit of difference. I'm assuming it's good (yes, I know) and it did seem harder to depress the inner ball.

So at this point, I'm stumped. Just for the heck of it I disconnected the fuel line @ the tank and heard air get sucked in so I wouldn't think I had air in the system.

Tomorrow I will crack loose the feed to the IP and see if it bubbles under prime but if not then what??

About the only mechanical thing besides the IP I have left is the LP; to install my HPFP 95.

Note - When it cranks for a bit I do notice a puff of black smoke out the tailpipe; seems to be a bit heavier than normal. Could my grid heater be causing it? Fired up almost perfectly this morning, though. Dunno fellas, I'm kindof at a loss.

Any ideas?

Thanks, Mike.

 

Readin through this stuff again and noticed that you have the fuel guge mounted on the supply side of the filter cannister. Is this the incoming or outgoing side of it. If it's incoming a clogged fuel filter may be part of this issue also. You should be reading pressure from the outgoing fuel side of this cannister.

We'll get it figure out it just may take a few tries.

 

Lookin at your first post and ponderin on this for a while it is deffinatley narrowed down to a fuel supply problem, so to start from the begining.

Do you notice this problem being worse some times more then others or is it a constant. The draw tubes inside the fuel tank have been known to crack and suck air in when the fuel is below a certain level.

Check all your fittings and make sure they are tight. If you have a leaker between the tank and the LP it can suck air in without leaking fuel out because it is pulling in under pressure.

If all this fails, you can pull the hose from someplace in the line after the LP but before the VP and run the hose into a bucket or somthing that you can measure the output amount. If the internal bypass is worn out on your LP you can possibly still have pressure in the lines but fuel is going right through the bypass and not moving forward to the VP. So in reality you are only moving air pressure in the lines mixed with some fuel.

OK, I just saw the signature you added. I hope you just forgot to list the real LP that you installed after you threw the Carter away. That stock lift pump, in no way shape or form will supply enough fuel to keep a hopped up truck supplied. Not even close. With the stock fuel lines still in place you may also just have some worn out fuel lines that are drawing air in through cracks. Once the truck is up and rnning it doesn't take much to keep it rollin but after it sit's and pulls air in through the cracked lines it has to reprime itself. But no matter what, you have to turn up your fule if your runin tha stock pump.

 

Thanks Uncle Bubba.

The guage is mounted on the supply side to the VP; so I guess the 'output' of the canister.

The replacement LP is an OEM design mounted in the OEM position but I don't have a fueling box, just mild timing - the HPFP95 is going in today. And I can tell the grid heater is working because of how it taxes the engine a bit during warm up - checked connections yesterday, too.

I will double check all the fittings, too.

NOTE: I just noticed this but the last couple days it seems to start pretty good in the AM (the first start of the day). This morning, it fired up fine - a puff of black smoke and then it was clean. Also, I've been testing under a couple different conditions and have noticed that if the truck is warm and running and I shut it down, I can immediately restart it, usually just fine - like it's normal. BUT if I let it sit for 2-4 mins, it's harder to start - still no white smoke, just a puff of black on start up.

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Got the HPFP 95 installed today; took about 3 hour total including making it look all pretty-like with tie wraps and such.

However it didn't fix my hard start issue. Still behaves like it did previously. Tomorrow I'll get under there and double check the fittings to be sure they're not leaking but, man, if that's not it I don't know.

I mean, I suppose it could be an IP but how do you know for SURE when it's running good?? I tried almost everything else. Is there any way to be sure fuel is leaking back to the tank??

Thanks, mike.

 

At the end of all this I would also recommend giving Chip at Blue Chip Diesel a call to see if he can help out. You can find his info in the sponsor section here and he probably knows more about VP44's then anybody else in the world that you will ever have access to.

You can also pull the pump and take it into an authorized Bosch service center and they can put it on the test bench to tell you for sure if it is the problem.

 

You can find a local service center here. Service Center Locator

 

I've been following your posts for the past couple of days, it's the reason why I became a member tonight. I've been having the same symptoms as you have. I also have a 99 24v 2500 w/76k miles, but I don't have any modifications to the fuel system. My hard start problem seems to be associated with the LP not turning on. When I place my key in the ignition and turn it to the on position prior to making the engine crank over my fuel system relay clicks. When I crank it the LP pump doesn't turn on as it's supposed to, or rather, it doesn't turn on every time. In the morning I have to crank it once, wait for the buzzer to stop then listen for the LP pump, if I don't hear it I pull the key out and try again. I usually have to do this a dozzen times before it works. If I continue to crank the engine it will eventually start after a couple of minutes. I'm assuming this is because the VP is doing all the work building up sufficient pressure which will eventually burn it out. I tested the voltage going into the LP and got 12vdc for the first second after cranking the key then the voltage dropped to 8.5vdc. When I did this test, I had run the truck earlier that day so whatever the problem is could have been masked, I will try this test again first thing in the morning. Regardless, I purchased a new LP, stuck it in, primed it, and I still have the same problems.
Other than the fuel system relay, are there any other switches that could block the voltage from getting to the VP, i.e. low pressure, water in fuel, other relays? I haven't been able to find good wiring schematics for the fuel system, does anyone have them? I can jumper my LP to my battery, throw in a switch, and it will work but it won't fix the problem. I hope it's not an ignition or ECM problem. MikeyM, do you hear your LP when you first start it in the morning? Hopefully we can help each other.

Thanks, Aaron

 

Your LP wont buzz everytime you turn your key on