I am baffled -- my truck acts like my LP is going bad, (12 psi at idle, 2psi at wot), this is through my edge attitude monitor, and I am getting no codes. when I drive the truck, it surges really bad under load, and seems fine at cruise on flat ground. Is this more than likely a LP problem? If so, what is the best after market Lp. I have read through the threads and cant come to a conclusion which one (or two) to go with. I just replaced the 47re two days ago and its killing me not to be able to drive this truck. (by the way if you want great customer care when replacing your trans -- Goerend is the place to go) Any help would be great !! Thanks guys

 

I went back out and started my truck today, and my check engine light came on, so I checked for codes and got 1693(DTC Detected In ECM Or PCM) and 1689 (No Communication Between ECM & Injection Pump Module) I have no idea what this means, I am hoping I dont have a dead IP.... Someone please chime in here....I am lost as to where to go or what to check next

 

anyone??? I need some help guys.......

 

Unfortunately, it sounds like you have ONE of TWO possible problems. You either have an ECM that's going south (someone had similar symptoms until they changed out their ECM) OR the electronics on the VP44 are starting to become faulty. Check all connections to each and make sure all connections are secure. High-load, high-heat situations can cause a borderline VP44 to show it's weakness if the electronics are having heat issues.
Oh, and I'd put an aftermarket pump on it ASAP!!! the pressures you're seeing at WOT are NOT good and mean that you're cruising pressures are still in borderline/unsafe range. I've got a Walbro setup on mine and it's been the best mod I've done so far. At WOT, I'm not even close to being in the 12 psi area of my gauge. The surging you're seeing at load is a combination of two things. First, the low fuel pressure means that the VP44 (which is cooled by the fuel running through it) is not keeping itself cool and the added heat in the VP44 is causing the electronics onboard to start to malfunction. Second, and the reason you're surging is because you're starving the engine for fuel. Power in the Cummins engine via the VP44 can be maintained down to 5 psi fuel pressure, beyond that, you will suffer performance problems. That being said, I would NEVER run a truck below 10 psi fuel pressure PERIOD!!! That is the critical pressure below which the VP44 becomes an issue. A correctly working fuel pump shouldn't be able to pull down below 10 psi. Hope this helps.

 

I had code 1689 when my ez went bad, which made me verry happy it wasn't the ip. When I unhooked it all drivability problems went away but I sent it to edge and had them test it anyway. A pressure gauge is the only way to tell if your lp is going dead or is dead, no codes for low/no fuel pressure.

 

Oh, and I'd put an aftermarket pump on it ASAP!!! the pressures you're seeing at WOT are NOT good and mean that you're cruising pressures are still in borderline/unsafe range. I've got a Walbro setup on mine and it's been the best mod I've done so far. At WOT, I'm not even close to being in the 12 psi area of my gauge. The surging you're seeing at load is a combination of two things. First, the low fuel pressure means that the VP44 (which is cooled by the fuel running through it) is not keeping itself cool and the added heat in the VP44 is causing the electronics onboard to start to malfunction. Second, and the reason you're surging is because you're starving the engine for fuel. Power in the Cummins engine via the VP44 can be maintained down to 5 psi fuel pressure, beyond that, you will suffer performance problems. That being said, I would NEVER run a truck below 10 psi fuel pressure PERIOD!!! That is the critical pressure below which the VP44 becomes an issue. A correctly working fuel pump shouldn't be able to pull down below 10 psi. Hope this helps.

 

thanks guys, I have not driven the truck since the day it started acting up, and it threw no codes on that day. I had not installed my edge until that night, to see what my fuel pressure was, started the truck, checked pressures, changed the fuel filter, got the truck to fire again right away (but still with low pressure showing on the attitude monitor). Started it again the next morning to see if my batteries had held a charge, and thats when I got the check engine light & the codes. (i have not tapped the pump wire yet) Could I have a faulty edge? Guess I will unhook it & see if the codes go away....and I have ordered a relocate kit from genos & a new aftermarket LP