Does anyone else have this problem. I have never had this happen before. If I let off too fast, the truck dies. It's done this since the SO VP44. My HRVP44 never did this before. Thank god I have a standard, just put her back into gear on the coast and re-start it. What causes this. Is my FASS not keeping up because the FP is good??? Thanks guys...

 

Its seems more of a problem with Edge products for sure, maybe Quad is having this issue too?

 

Hmm, ever since I changed my VP44 back in the spring I believe. If I let off the throttle and I am coming to a stop. My truck sometimes sounds like it is going to die. It last like 1-2 seconds and you can barely hear it, but there is a stumble in the RPM's. My truck has never died from it though.

 

Mine was like you just turned the key off...

 

Are you at WOT before you let off? What boost level and for how long? Are you letting off quick enough to bark the turbo (or at least hear the air going back through it)?

Paul

 

Pretty much WOT. I did get bark..

 

You are cavitating the pump and getting air in the injection lines... Best way to prevent is to not jump off the throttle as hard... ease off instead... Will prevent 99.9% of the time...

 

It's what is commonly called "air locking" the VP44. The more boost you run, the larger the injectors, and the harder you press the VP44, the more likely it happens. For what it's worth it was harder for me to get it to happen when I had a HRVP44 on too. The best cure is to roll out of the throttle instead of chopping it. If you're barking the turbo, you are probably letting out of it to quick.

Paul

 

10-4 guys, Thanks..

 

What does seem kind of weird to me, is that your mods are not that extreme, and though I would expect it to happen, it doesn't seem like you would be having the problem this often. I can do it on demand with my truck, but it has become second nature to avoid the situation that causes it. I still do it a few times every year at the track.

Paul

 

Man...i have been down this road with about 4 different guys.......

One thing i have seen with a few of them is they had larger lines and drilled connecting tubes......

My theory is that when you ask for a ton of fuel, and then jump off...the pump just shuts down and the lines are just temporarily empty from the high demand of larger injectors and throttle input....this lowers line pressure to the point that you do not over come the pop-off pressure of the injector....or retard the pop-off to the point that the engine will not run. I think its more of a "Price you pay" for higher HP goodies and need to adjust driving style to accommodate….until someone actually figures out a fix…. I am almost certain that its on the VP to injector side of things…….Maybe a VP that is able to put out more volume might solve this issue…..who knows……

If you were out running the FASS, you would see fuel pressure down at 0 PSI.

 

You'd be surprised how little mods it takes to generate these symptoms... I did it with an Edge EZ and DD3's... I was also able to track down part of my problem to #6 injection line being a hair loose....

 

Dan, I am seeing 0 psi with my FASS with the Adrenaline FP sensor, that's what I dont like!!! I have no idea what's going on here with this truck of mine!!! I getting this bad shudder when I'm on the throttle with the box on. Turn the box off and it doesn't seem to be there. Remove the wire tap, turn the box on and there it is again. Hard runs and the fuel pressure drops down to 0-2-0, etc... Changed out boxes and the same results with the other one. I changed the APPS, MAP and AIT sensor and no luck, still there. I have to test the fuel pressure with another guage to see if I'm actually dropping to 0psi. This is just about driving me to selling this truck. I'm guessing it has to either be my new SO VP44 or the ECM if it's not a fuel problem???

 

I had/have that engine stop dead syndrome too.............but I don;t think its supply to the pump that causes this shutdown scenario. your 0psi may or may not be related I don't know but I know I was seeing a solid 10 psi when my truck was shutting down........

it was always after a long hard root on the throttle, never payed much attention to how I got off the throttle until doing some research about it. when I had the 150 horse injectors in it would take a couple roots on it in a row, when I put the DDP comps in I could kill it it on demand with the Smarty on 9......

may or maynot Recall at our Dyno day....I vanished for about an hour?

I killed the engine by accident snapping off the throttle like a dummy.....going around the block trying to warm up the pig..........Tate had to come boost be cause I killed the batteries AGAIN trying to prime it back up.

 

Defiantly double check that reading with another gauge.....Run our pump with the engine off....see if you have return fuel going back to the tank via the FASS return line. You can pop the fuel cap off and listen for the fuel...if you have return fuel...more than likely you have pressure because that fuel has to overcome a 12 PSI restriction before it sends fuel back via that line.

I don’t like electrical gauges and VP-44’s. They mix like oil and water. I get almost the same amt of issues with them as I do with fuel pressure isolators leaking down.

BUT i would talk to some others with the Adrenaline.....i have heard that is a known issue with them...the surging at least.