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Hard hot start causes

ak diesel driver

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So I put a brand new pump on my truck and still have a hot start issue. What other things could cause this besides worn head and rotor?
 

ak diesel driver

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I might also add that in the past I have been alble to pour water on the old pump and have it start right up but now the engine has to cool off completely, the water trick doesn't help
 

WarWagon

Well it hits on 7 of 8...
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Bad lift pump. Slow crank RPM. Just saying the spec is higher RPM hot than cold IDK why. Injectors sticking or other issues.

New IP means what exactly? Virgin new, rebuilt, used, new to you?

I assume you have checked air in fuel and fuel quality. Have you loosened a injector line to see if it's putting fuel out at all?
 

ak diesel driver

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Good LP 14psi to the IP. Brand new not rebuilt. Clear line shows no bubbles.
I put a new PMD on direct to the pump (no extension cable). Letting it warm up now to see what if any difference it makes. I'll loosen a line if that doesn't work.
 

ak diesel driver

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I am getting some fuel but it does take a bit of cranking before it starts showing up.
One thing I did notice is that if I turn the key to the run position ,and wait until the LP quits running, the pressure drops almost instantly. Thinking maybe a check valve went bad. The thing that makes me question that is why does it start good cold?
 

WarWagon

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the LP quits running, the pressure drops almost instantly.
Good clue and, yes, this is a problem. Massive leak somewhere. (What lift pump and what rig because I assume a stock or Walbro plunger pump?)

I'll hold the rant on leftover check valve eating Meth in Biodiesel that's added as a % to diesel almost everywhere now.
 

ak diesel driver

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This is on my 99. Running a raptor LP. Using hose pinch pliers right behind the FFM the pressure drops rapidly but will show about 2 PSI on the gauge
 

ak diesel driver

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So before cutting into my stock hard lines to install a check valve I talked to a buddy of mine who owns his own shop. He suggested trying some ether to see if it was a fuel supply issue. Basically if it starts without stumbling at all then the IP isn't letting fuel through. So I cycled the glow plugs so they weren't on and my wife cranked it over for me and with just a tiny shot it fired up and ran smoothly. So I'm starting to think my "brand new" IP isn't working right
 

NVW

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IDK, One engine will start cold and not smoke and another will start much quicker and smoke like crazy. As long as they start I have been happy. The one which is a cold stater is slower when warm. ?
 

NVW

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Makes no sense to me if air isn't a part of the problem. Would a warn engine create a lose hose connection somewhere?
 

Twisted Steel Performance

Anything worth doing is worth overdoing.
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Maybe before you drive that far is their another truck you could swap IP's on and see if it follows the IP, might rule out the IP and save a trip..
 
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