Engine/Transmission (1998.5 - 2002) truck wont start on its own

[Pfekete]

hello, I have a '99 24 valve, and it wont start on its own like normally should, I have to ether it to life, it acts as if the rpm's get high enough it will run on its own and idle fine run fine but if I bring the rpm's down by letting the clutch out around 500 to 600 rpm it jerks real hard and just stalls like someone turned off the key. My thoughts were that maybe my compression is low, or the injection pump cant produce enough pressure to make the injectors spray at low rpm. I have 2 supply pumps going to the injection pump at 20 - 30 psi, I checked to make sure I have fuel as close to the vp44, it sprayed all over as soon as my supply pumps kicked on. the only thing I've done different is I o-ringed the head after i blew a few head gaskets due to boost, it ran fine a few days but now its not. Any input would be appreciated, Thank you

 

[Pfekete]

I messed around with the truck today some and found something that doesnt make any sense to me. the truck will not start, no codes come up, if I unplug the supply pumps so that there is no fuel pressure the truck fires right up, runs fine I can bog the engine down and it catches itself with a lot of smoke out of the pipes, as soon as I hook the supply pumps back in the engine sounds like its struggling to run, the rpm drops slightly, has no power, and stalls immediately if I try to even bog it down. I am very confused about it.

 

[Mad Bomber]

You have to have the 2nd pump on a trigger wire so it won't start pumping till it starts. Starting PSI is about 4 LBS. I've have a 2 pumps system and was around 21 to 23 PSI at idle no problems for 3+ years. Since then I went to FASS

 

[Pfekete]

the problem I have just happened recently I have not changed anything to the fuel system or the electronics in over a year, I never had any problems prior to this with starting or running.