99 24v Stalling problem...

BlackSkyRacing

BlackSkyRacing

Living Under a Rock
Joined
Mar 22, 2007
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1,394
Ok, I'm not quite as versed with the 24v trucks as I would like to be. But a shop that I work for had a 99 CTD come in that starts and runs but only drives a few blocks before losing power and eventually stalling out. So, here's what they tried before calling me (even though I wasn't much help)...

Fuel pressure is 10psi at idle and holds at 10psi at a free rev to 2500. They also changed the fuel filter and checked the overflow valve... The guy working on it said that he could actually blow through the overflow valve by himself... Not with shop air, but by actually physically blowing through it.

They have yet to drive it while watching the fuel pressure, so that's what I plan on doing tomorrow. I get a feeling that for some reason the fuel pressure is dropping off. I wonder if the in tank screen is plugged up... How might someone go about checking how much vacuum is being pulled on the intake side of the pump? Maybe that would be a good way to check whether or not that screen is plugged without dropping the tank?

I guess the thing I'm wondering, is whether or not this would have effected the IP or not. It seems to hunt for it's idle speed in about the same way a 12v does when the governor gets worn out... The truck has 204k on it and to my knowledge it is the stock pump.

Any help or suggestions would be helpful.

Thanks

EDIT: Oh I forgot to mention that it won't restart right after stalling, but if you wait 10-15 min it will restart and run for a short amount of time.
 
Check for codes for the lift pump. Also check the fuel psi for the lift pump. Then after all that check for codes for the vp44. And the last thing is after everything checks out there is a relief valve on the vp44 and it could stick open (very uncommon). Hope this helps out.
 
99xlstroker said:
Check for codes for the lift pump. Also check the fuel psi for the lift pump. Then after all that check for codes for the vp44. And the last thing is after everything checks out there is a relief valve on the vp44 and it could stick open (very uncommon). Hope this helps out.
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Light's not on.. But if it means I get to play with the new $9k Snap-on scanner then I'm all for it :P

Big Blue24 said:
Does it smoke a lot when it loses power right before it dies?
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I haven't driven it myself just yet, they did... Could you by chance share what you are thinking should it smoke excessively :poke:

EDIT: I forgot to mention the tow truck guy that brought it in likes to tinker at the shop and was the one that was messin with it. He has a 94 CTD tow truck so he's kinda in the same boat as me about knowledge on 24v trucks.
 
My truck ran for months with 0 psi fuel pressure. I would look else where.
 
Limited said:
My truck ran for months with 0 psi fuel pressure. I would look else where.
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Dude i cant belive that your truck ran for months w/o any fuel psi. it is just not possible for that truck to run, that vp44 needs all the fuel it can get.
 
BlackSkyRacing said:
Just for reference... What does a faulty Cam Position Sensor do?
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Its could cause the problems you are describing.

That fuel pressure is more than likely in the danger zone when driving under a load. That needs to be fixed also.
 
haloman said:
Its could cause the problems you are describing.

That fuel pressure is more than likely in the danger zone when driving under a load. That needs to be fixed also.
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Ok that's what I was kind of thinking with the CPS... I plan on puttin a new overflow valve in it (like a said you can blow through it on your own [no shop air]) and taking a FP reading while driving too. I want to make sure that there aren't any problems with the fuel delivery end of things so I don't have to worry about it coming back because the pump died and it be "our fault".

EDIT: BTW should I suggest a walbro pump (and have to wait on it) or a Holley Blue and just get one from the local parts supplier today should the lift pump be toast... I suppose that depends on how long the customer wants to wait.
 
:rockwoot:Yeah buddy my truck ran for 4 months with 1 psi fuel pressure at idle, 0 as soon as you put it in gear. That was with a Smarty, Jammer 4's, and 3 hooks to the sled. I replaced the VP, although it still ran fine and it is still runnin good now, been on another truck for 6 months. That pump has over 160k on it too!

I love my VP44!!!:shake:
 
dude my buddy has a 99 24v with well over 270k on it with the stock vp44 pump on it. i does have a fass lift pump though... He has the edge and smarty on his truck and it runs just fine
 
Black Sky, it kinda seems like your losing fuel prime. I had this problem, but it looked fine on the guage because it was after where I mounted the guage.



Side note, contrary to poplular belief, their are many of us that have had great luck with VP44's, as stated above. However, you only hear about when they fail, which creates a bad impression.
 
Limited said:
Black Sky, it kinda seems like your losing fuel prime. I had this problem, but it looked fine on the guage because it was after where I mounted the guage.



Side note, contrary to poplular belief, their are many of us that have had great luck with VP44's, as stated above. However, you only hear about when they fail, which creates a bad impression.
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I was beginning to think the same thing... It takes longer than it should to take off when cranking it. There isn't any type of check valve in the fuel system is there? Or is that the Overflow valve's job? Maybe pin hole in a rubber line letting it drain back? I'll check it after I replace the MAP sensor and take it for a spin to see if resetting the minimum TPS voltage solved his low/surging idle and stalling issue.
 
My old 01 would suck down to 0 psi at WOT for several months before I knew it. It had a drag comp and 150hp injectors. I put a fass 150 on it and its still going strong on the original vp with over 220k.
 
there is a relief valve on the vp pump itself. look on there to see if you just dont have a stuck valve. At wot you should have 10 psi min.
 
99xlstroker said:
there is a relief valve on the vp pump itself. look on there to see if you just dont have a stuck valve. At wot you should have 10 psi min.
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After replacing the Overflow valve I re-tested the FP and it came up to 14psi @ idle and would draw down to 9-10 @ WOT. That's before I figured out that a little over 1/8 tank wasn't enough fuel... Noticed I could drive it trouble free for a bout five minutes after letting it sit overnight and that it would start to act up the worst on inclines. Friggin fuel was getting aerated from being too low. The return must have been making it foam up and when you would go up or down a hill the liquid would slosh away and leave the foam by the pick up. That would get air in the system and that would be the stalling and restarting issues :bang

Put $10 worth of diesel in it and that end of it was solved. Still needed the Overflow valve and the MAP sensor though; was a gutless pig without them.

Thanks for all the help guys.
 
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