Modified fuel system help

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rattlebox93

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Sep 10, 2008
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ok first off i have 6x16's clipped 4200 spring timing advanced 1 tooth and pump in normal stock position somewhere in the middle boost refrenced reg and a 150gph 15 psi aeromotive fuel pump and i am running -6an lines directly into the injection pump and not running any of the crap small factory feed line or factory fuel filter thing in the head....ok so if u really get after it and then get out of he throttle it will run really rough and sometimes die after putting the electric pump on it is much better but i will still do it i have my initail fuel pressure @ about 10psi and have the boost refrencing hooked up and the pump is going wide open once boost is applied anyone have any ideas as to waht my problem would be? internal vain pump in the injection pump bad? injectors too big for a worn out injection pump to handle? the injection pump has less than 150,000 on it and has only been modified (turned up) for about 25,000 well any help would be greatly appreciated and its not like the truck dosent run good because i runs really good actually it will rip the back tires loose @ 50mph in 4th just rolling into it so i cant see it beeing anything too major thanks again dj
 
Until an actual "fix" can be cyphered, you're gonna have to lean to roll off the throttle after a WOT blast instead of side-stepping it.

I figure: combustion chamber pressures (compression ratio + boost at that second + etc) are still high enough after the injection event has occurred to have charge-air back up into the nozzles. You're basically air-binding the injectors much like happens when you run out of fuel.


The second one cuts the fuel, the turbo(s) still haven't un-spooled (so to speak) and as a result, there's till substantial pressurized charge-air going into the cylinder with the next intake stroke. Bring up the compression stroke and there's a lot more PSIG than would normally be seen with a greatly smaller injection event (idle).

In a minor occurrence, the engine runs rough as though one or two cylinders aren't firing. Revving it up once or twice usually clears the injectors and all is well.
A more pronounced occurrence results in the engine flat dieing once the engine has unwound. You've got to get out and crack an injector or two's feed-lines and burp the air. (HURRY! The freaking turbo(s) are still glowing from that 1/4 mile pass! :doh: )

A few folks suggest a blow-off valve might help, but then it doesn't know the difference between WOT boost and after WOT boost.

Just learn to roll-off the throttle slow enough that the turbos can spool-down and the engine consumes the excess boost. ;)


I've asked the same question ~ Is it possible . . . (?) - Competition Diesel.Com - Bringing The BEST Together
 
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I have a 90 model tug truck that does this same thing. The more it's turned up, the more it wants to die when you let off the throttle quickly.
 
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