I have a 01 CTD fires right up every morning and runs great. If I shut it off, when I go to restart it it cranks times as long befor it fires. I just got a Po121 or 120 APP signal. Would this cuase a long crank time? I have 19 PSI at inj pump inlet.

 

Sounds like the same problem I'm experiencing right now. I have the same issue with hot starts / long cranks, it just hasn't given up yet. I'm leaning towards "heat soak". Basically, the computer in the injector pump is wearing out due to heat from the engine. I'm pricing pumps as we speak. Don't know about the code though, I haven't gotten a code yet.

 

I am going to replace my APPS/ TPS.

 

next time its HOT unplug the lift pump and see if it starts, if it starts right up your VP44 is dieing, shut it down and reconnect the LP your pump has a bad or cracked diaphram if it makes no diff. it could be electronics

 

That's what my VP44 acted like before the electronics gave out. It got worse over time till it would no longer start at all.

 

If you guys have a FASS, Airdog, Raptor, or similar output aftermarket fuel pump then your fuel pump is placing to much pressure on the VP during engine cranking when the engine is hot. Not a big deal but does require installing a simple relay to override the ECM. If you have one of those pumps then you can identify the problem by unplugging the fuel pumps inline fuse located in the aftermarket wire loom when the hard hot start problem happens. Just dont forget to put the fuse back as soon as it starts.

If you have the OEM lift pump and you're experiencing the hard hot start issue then more than likely the problem is the VP's computer is overly hot, shorting out while hot, and is not far from failure. The easiest way to tell if this is the problem is to pour a gallon or so of cool water on the top of the VP when this hard start problem happens. The water will cool the VP's computer and allow the truck to start.

 

It was my starter!