Is it possible . . . (?)

TheNatural31 said:
It's do to excessive case pressure being discharged after the throttle is lifted. With a VE you will get smoke or what you call burp, with a VP44 the truck often dies. The return side is too restricted being the reason.
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What I get is air in the injectors that often results in the engine dieing with coming back to idle. I have to loosen the injector feed-line and "Burp" the air out of the line at the injector. Same thing that would occur if you just plain ran out of fuel.

When I get off the throttle quickly after a burn-out (for example), there is no smoke as far as a puff or anything like that. The engine just unwinds and lopes bad with two or three cylinders not hitting. Same thing at the end of a pass.

Running tonight, cutting 1.75 60's and such, it wasn't as bad an issue when I made a conscious effort to ease off the throttle at the top-end (The problem with that chit is at least one 1/4 mile track around my house has a rather short slow down section >coughFayettvillecough< ). Still had one or two cylinders miss a little but they would eventually clear-up with revving the engine.

- I guess my main concern is the hot turbos coking oil while I'm dicking around squirting raw fuel on the hot manifold trying to get the crap to fire back up. :bang

Thanks for the replys folks. ;)


EDIT: Talking about the return side of things FWIW:
- I've got the injector return line converted to -4AN just behind cylinder #6.
- I've got the IP return line converted to -4AN about 6" away from the IP.
- Those tie into a return fuel rail of sorts that includes the -6AN return from the fuel pressure regulator.
- That return fuel rail has a -8AN line going to a fuel cooler and then back to the tank's pick-up reservoir.

Is that the return section/system you're talking about?
 
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Bustedknuckles said:
Is there any fix for that or anything you can do to help that? My brothers truck does it everytime if he doesn't ease off the throttle after WOT.
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After lifting off the throttle fast just give the throttle pedal a couple quick bumps before the engine dies and the pump should push the air back out of the injectors.
 
soggy said:
Why does this happen? Where does the air come from?

I also have an A1000 and run at 21 psi, still happens when I lift too quick.
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I've seen it many times, some do it, some don't. I've seen so much variation between distirbutor pumps that it doesn't surprise me.
 
JAyers93 said:
Ive never had this problem with combo's of: piston lift pump, A1000 setup, 12mm pumps, 14mm pumps, POD's, 6x.016, or 6x.018 VCO's.

Ill do some research this weekend and let you know what I can come up with.
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You ain't hittin it hard enough. :poke: :evil :bigsmile:

. . . Thanks guys. ;)
 
So this only seems to happen to vp and ve trucks not to p-pumps and commonrails?

Do p-pumps have a larger return line on the injectors or are they not set up that way?

What if us ve guys drilled out the hole in the restrictor doo-hickey banjo on the back of the ve pump for the return?
 
GLHS said:
What if us ve guys drilled out the hole in the restrictor doo-hickey banjo on the back of the ve pump for the return?
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I was under the impression that restrictor, pared with the vane pump is what maintained case pressure (RPM based).
 
Safe to assume you and I don't have case pressure guages BC?

Maybe if we had one set up we could see spikes occuring.
 
GLHS said:
Safe to assume you and I don't have case pressure guages BC?

Maybe if we had one set up we could see spikes occuring.
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It appears we're the only ones. :bang

I know the case pressure does spike (or at least that in the port that feeds the H/R) as in the case of stock/OEM injectors on a turned-up VE will result in tearing plugs of rubber from the fuel shut-off solenoid's tip, when getting on the throttle hard and not rolling off of it. That issue appears to be eliminated with running larger injectors.

I've got the means of monitoring the case pressure via an unused DATA-logging input. I just have to get a sensor and install it in the case. That last part is a problem. If I'm gonna pull the IP and take it apart far enough to drill and tap a port in the case, I'd just as well go ahead and bomb it. I would prefer to have a second IP to work on as such though.


. . . . . working . . . .
 
I was thinking of joining the "pull cable crew" and just tapping the fuel solenoid for a guage port.
 
Talked to Giles at Performance Diesel Injection and he says he thinks there is air getting into the injector from lack of fuel "pushing" so to speak from snapping the throttle shut quickly.

Seems we have this problem with big injectors.

I never had this problem when I had the 65 lpm 5 hole nozzles but, now have it with the 73 lpm injectors.

Installed the 67 lpm 4 holes but have not run it wide open yet.

He also thought there may not be a solution except to back out slowly.
 
Great thread!
I have been having a problem with air in the injector lines too. It doesn't stall, but definitely runs rough after a good run and getting out quick... I am running either pods or stock non I/c injectors. Been searching the supply side for leaks, but this makes way more sense. I am around the 400whp range.
 
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