My buddy has a 98.5 24 valve with a comp, injectors, and a Industrial Injection hot rod pump. He has a carter pusher pump on it making almost 30 PSI at idle, and no less than 12-15 at Wide Open. He only has maybe 10k miles if that on his injection pump. I was following him to a buddies house the other day, and he mashed it in 3rd gear with the box on, and when he let off, it just died. He rolled across the intersection, and I pulled over. It refused to start back with the starter, and wouldnt hit a lick(good batteries). So I cracked 2 injectors lines, and he cranked it. It was squirting some fuel out, but it still wasnt hitting a lick. So finally I got behind him, and pushed him, and stopped. He dropped the clutch in 3rd, and it fired right up no problem. It has done it to him again already, and only does it with the box on when he really hammers on it. It also has a miss with the box on while revving it up slowly. And also in gear going down the road when you run it hard. He says it doesent have the miss or die with the box off. Does he have a bad comp box, or is his injection pump just on the way out already? He has had a lot of trouble with this truck so far. He just got it out of the shop the day it started acting up, so I was just wondering what you guys thought. thanks

Eric

 

It sounds like the box. Tell him to call Edge Products, and they'll help him out.

 

Sounds like normal for a VP44 truck.

The problem is he's letting out too quickly...it causes the truck to die and not start without cracking the lines.

I have seen this condition with several trucks and got them running again.

Nothing to worry about...just dont let off so quick...

Both HRVP44's and stock VP44's will do this.

 

I've never had this happen to my truck. To me that doesn't sound normal.

 

happens to me all the time with my HO, 150's and comp box.

this is how it was basically explained to me-
when you are at WOT the vp is flowing at pretty much max capacity with the box and injectors, and when you let off really quick from WOT is causes a cavitation in the VP and will pressure lock the lines with air that needs to be bled from the lines. i havent had it happen in awhile but it used to happen so much i kept a 3/4" wrench in the console.

 

As mentioned above, this condition can be a normal occurance on a bombed truck.... When we race bombed trucks once across the finish line we shift into neutral and rev the engine to help ensure it stays running. Same thing on a dyno pull. Not all trucks do this is seems to be dependant upon fueling mods and the more mods the more prone this is to happen.

If it occurs again have your friend crack injection lines 1,3,4 (easiest to get to) and crak the engine until good fuel flow occurs. Retighten each line as fuel flow is normal and truck will fire right up. It will run rough for a few seconds after startup but should run fine after that.

Doug Smith

 

That is n ot normal. I can run my 99 anyway I want to and it runs fine. Original VP-44.

 

This normally does not happen on a stock truck. You will normally see this happen on a bombed truck.... It seems the higher the HP the more prone to this condition.

Doug

 

How can a closed system suddenly pump air into injector lines? Where would the air come from? THIS, dosen't make sence.

 

This can happen. When you cavitate a pump, air bubbles are formed from negative pressure. It is caused by trying to pump more liquid than is available. It can tear the crap out of a pump if left cavitating too long.
Ask any Firefighter who is a beginning pump operator.

 

One more thing to worry about.
I've never seen it...even with TST Comp on full and shudders (cavitation?) galore!
Only time I will ever come off it that fast is a 1/4 mile run.... but no problems yet; maybe that's one in the win column for the FASS Air Seperator?

RJ

 

negative...i have FASS and ive had it happen before...might be a manual tranny thing...pushing in clutch and unloading the engine WAY too fast???

 

Cavitation usually happens on centrifugal pumps. I suppose it could happen on our pumps, but I don't even know wht kind of pump is in a VP44.

 

My truck has now started doing the same thing. I just shoved it into gear before i stopped rolling and let out the clutch to start it up again.

Some times in the morning, my truck dosnt have fuel to the injectors. Because it wont start. And i think i have come to the conclusion that i shut it down too soon and dont let it get fuel back through the lines.

 

I have read the VP-44 internal pump is a rotary vane pump (never had one apart, myself).

The FASS has a gearotor!

RJ