Attention: TDR Forum Junkies 
I am posting this in the hopes it will be of some help to another person who, like me, isn't necessarily "wrench retarded" by any means but is sometimes daunted by the complexity of diagnosing problems with these beasts. If you're not interested in the "saga" version, jump to the bottom for a summary of my hard-knocks lesson. But it may be instructive for some to follow my admittedly flawed thought process as an amateur "shade tree" mechanic.
See my mods in the sig. Truck now has 185,000 miles, of which over 150,000 have been with the performance mods. In that time, I have had to replace numerous lift pumps and two VP44s. I have always had the Drag Comp and have always run with the pump wire tapped (soldered).
Since going to the Glacier kit and Walbro pump a few months ago, my VP44 has never seen less than 14psi and usually gets a steady 16. For reference, I mounted the Walbro on the frame rail forward of the tank, but chose to keep the factory fuel filter. My fuel pressure gauge is tapped at the supply line banjo bolt at the VP44.
My truck is a daily driver - empty. It hauls horses, cows, or camper trailer a handful of times per year. It has only been on the dragstrip once and, although I don't think I'm rough on it, I don't baby it either. We have a few Ford notches on our pistol...
Christmas Day here in Colorado we had miserable weather. Cold, snowy, icy, temps in the single digits to teens. My wife and I drove seperate rigs to the inlaws because I had to return home and go to work the next day.
Prior to getting there, I topped off with fuel which required a little over half a tank, and I added PS fuel treatment - gray bottle. The trip to the inlaws was uneventful, other than the weather. I commented to my son how similar it was to my recent drive from Indianappolis to Denver through the midwest blizzard you all heard about on the news earlier in December. My truck's Ranchhand bumper and grill caked up with ice, and ice was hanging from literally everything underneath.
At Grandma's, we shut the truck off and went inside. My truck sat for approximately 10 hours in low teens and single digit temps. I parked in a foot of snow and another 6 inches fell. For reference, I plug my truck in whenver possible during this kind of weather but regardless, have never had cold weather start issues. No plug was available here.
At 10PM, I headed out. The wait-to-start light came on a reasonable amount of time for the temps, and I started cranking. The truck fired immediately and I gave it some pedal. It didn't feel right so I kept my foot in it and revved it a bit. It ran rough. That's the best way I can describe it. As soon as I let off the pedal, it died as if starved for fuel. After that, I could not get it to catch and fire again.
Fuel pressure gauge read normal, I knew I had fuel, but nothing worked. Stunned, I looked for issues. I turned on the key and noticed that no lights were on on my Comp box. This was new. Having no other good ideas, I decided to eliminate that as a possible cause. I removed the Comp and it's harness. Still no luck.
I began to think - "what just changed?". Most recent event was topping off with fuel. Wondering if I got some bad stuff, I drained the fuel filter, bled out 3 injector lines, and tried again. This got the same result as before - Truck fired, ran rough above 1500 rpm, but as soon as I let it down to idle, it died as if out of fuel. Then I dumped one bottle of PS 911 (red bottle, water remover) into the tank and used another one in the fuel filter cannister. Bled injector lines, tried again, same result. Started, ran rough, no idle, and died.
Codes were now set but in my haste I had not checked for codes before removing the Comp box. I knew I could have caused codes that way but wasn't sure. 1693 was set but who knew what else?
I borrowed the father-in-laws truck to get home and to work the next day, and began making calls. I talked to three people - two mechanics I knew and trusted, and one mechanic closer to the truck who could do roadside repairs.
All three agreed that, although not conclusive, given my mods, my history, and the symptoms, a failed VP44 was high on the list of probable causes. I went down the following weekend with my little code reader and found that no codes were specifically related to failed VP44 but - as all three mechanics (and a few posts here on TDR) will confirm - a VP44 failure will not always throw a 0216.
In spite of my mods, my truck and I are getting to a stage in life where reliability and cost to keep on the road are more important than beating a Mustang at the light. I began soul searching. Was it time to dump this critter for a more reliable truck? This would be VP44 number three. And I hunt and fish in wild and wooly places. The prospect of my truck leaving me stranded is not a happy one.
But when I considered the cost of swapping this paid-for rig with all my accessories for a new truck payment and starting over, I decided it was time I grew up and learned how to do my own VP44 swap. After all, everybody knows that ol' Cummins has a lot more miles left in it, if I can keep the rest of the truck together.
I ordered a pump. It came and with some trepidation I started in after watching the videos that are helpfully posted elsewhere on this site. It really turned out to be not that big a deal and I was pretty pleased.
As I bled out the injector lines, it was my impression that the amount of fuel spraying out of lines 1 through 4 was significantly more than what I'd seen with the old pump. I got excited.
After everything was together, I tried to start it. It took some cranking but finally caught and roared to life.
Kinda.
It "seemed" a bit smoother but still had some stumbles at higher rpms. The final test was when I eased off the throttle and approached idle. Sure enough, below 1000 rpm, it choked off and died - as if out of fuel. Fuel pressure read 15psi.
Dang.
I fought back a panic, and logged back into the TDR. I searched and searched on my symptoms. I began to worry one of the million sensors on this dumb thing might be bad and me, with no diagnostic equipment (and no clue), would be buying sensors one by one, hoping to hit the jackpot. Crank shaft sensor, camshaft sensor, map sensor, tps sensor, dumbdriver sensor... on and on...
Then I stumbled across something that caught my eye. I read a post where someone said a Walbro pump should run absolutely quiet. If you hear any ticking noise from a Walbro, that means it's cavitating or sucking air. I remembered Chrismas night when my son was standing at my window while I thrashed my starter trying to raise the dead. He said, "what's that ticking noise?" I had checked, and it was from the pump, but I figured it was just a coincidence and ignored it at the time.
On connecting these two dots, I went down to the garage for a look see. There was a small puddle of diesel on the floor under my tank/pump area. I cycled the key to run the pump and, sure enough, the Walbro was making the slightest of ticking noises. More importantly, a few more drops of fuel fell to the floor. I looked underneath, expecting to find a loose hose around the pump, but all I could find was that the tank was wet on the outter side and the leak must be from somewhere up above.
I disconnected the fuel line from the input side of the stock fuel filter and put it in a bucket. Sure enough, when I cycled the pump, the fuel was coming in bubbly - almost foamy.
I'm no genius, but that couldn't be good. I made up reasons in my head why foamy fuel would create exactly the symptoms I had.
(continued next post... )
See my mods in the sig. Truck now has 185,000 miles, of which over 150,000 have been with the performance mods. In that time, I have had to replace numerous lift pumps and two VP44s. I have always had the Drag Comp and have always run with the pump wire tapped (soldered).
Since going to the Glacier kit and Walbro pump a few months ago, my VP44 has never seen less than 14psi and usually gets a steady 16. For reference, I mounted the Walbro on the frame rail forward of the tank, but chose to keep the factory fuel filter. My fuel pressure gauge is tapped at the supply line banjo bolt at the VP44.
My truck is a daily driver - empty. It hauls horses, cows, or camper trailer a handful of times per year. It has only been on the dragstrip once and, although I don't think I'm rough on it, I don't baby it either. We have a few Ford notches on our pistol...
Christmas Day here in Colorado we had miserable weather. Cold, snowy, icy, temps in the single digits to teens. My wife and I drove seperate rigs to the inlaws because I had to return home and go to work the next day.
Prior to getting there, I topped off with fuel which required a little over half a tank, and I added PS fuel treatment - gray bottle. The trip to the inlaws was uneventful, other than the weather. I commented to my son how similar it was to my recent drive from Indianappolis to Denver through the midwest blizzard you all heard about on the news earlier in December. My truck's Ranchhand bumper and grill caked up with ice, and ice was hanging from literally everything underneath.
At Grandma's, we shut the truck off and went inside. My truck sat for approximately 10 hours in low teens and single digit temps. I parked in a foot of snow and another 6 inches fell. For reference, I plug my truck in whenver possible during this kind of weather but regardless, have never had cold weather start issues. No plug was available here.
At 10PM, I headed out. The wait-to-start light came on a reasonable amount of time for the temps, and I started cranking. The truck fired immediately and I gave it some pedal. It didn't feel right so I kept my foot in it and revved it a bit. It ran rough. That's the best way I can describe it. As soon as I let off the pedal, it died as if starved for fuel. After that, I could not get it to catch and fire again.
Fuel pressure gauge read normal, I knew I had fuel, but nothing worked. Stunned, I looked for issues. I turned on the key and noticed that no lights were on on my Comp box. This was new. Having no other good ideas, I decided to eliminate that as a possible cause. I removed the Comp and it's harness. Still no luck.
I began to think - "what just changed?". Most recent event was topping off with fuel. Wondering if I got some bad stuff, I drained the fuel filter, bled out 3 injector lines, and tried again. This got the same result as before - Truck fired, ran rough above 1500 rpm, but as soon as I let it down to idle, it died as if out of fuel. Then I dumped one bottle of PS 911 (red bottle, water remover) into the tank and used another one in the fuel filter cannister. Bled injector lines, tried again, same result. Started, ran rough, no idle, and died.
Codes were now set but in my haste I had not checked for codes before removing the Comp box. I knew I could have caused codes that way but wasn't sure. 1693 was set but who knew what else?
I borrowed the father-in-laws truck to get home and to work the next day, and began making calls. I talked to three people - two mechanics I knew and trusted, and one mechanic closer to the truck who could do roadside repairs.
All three agreed that, although not conclusive, given my mods, my history, and the symptoms, a failed VP44 was high on the list of probable causes. I went down the following weekend with my little code reader and found that no codes were specifically related to failed VP44 but - as all three mechanics (and a few posts here on TDR) will confirm - a VP44 failure will not always throw a 0216.
In spite of my mods, my truck and I are getting to a stage in life where reliability and cost to keep on the road are more important than beating a Mustang at the light. I began soul searching. Was it time to dump this critter for a more reliable truck? This would be VP44 number three. And I hunt and fish in wild and wooly places. The prospect of my truck leaving me stranded is not a happy one.
But when I considered the cost of swapping this paid-for rig with all my accessories for a new truck payment and starting over, I decided it was time I grew up and learned how to do my own VP44 swap. After all, everybody knows that ol' Cummins has a lot more miles left in it, if I can keep the rest of the truck together.
I ordered a pump. It came and with some trepidation I started in after watching the videos that are helpfully posted elsewhere on this site. It really turned out to be not that big a deal and I was pretty pleased.
As I bled out the injector lines, it was my impression that the amount of fuel spraying out of lines 1 through 4 was significantly more than what I'd seen with the old pump. I got excited.
After everything was together, I tried to start it. It took some cranking but finally caught and roared to life.
Kinda.
It "seemed" a bit smoother but still had some stumbles at higher rpms. The final test was when I eased off the throttle and approached idle. Sure enough, below 1000 rpm, it choked off and died - as if out of fuel. Fuel pressure read 15psi.
Dang.
I fought back a panic, and logged back into the TDR. I searched and searched on my symptoms. I began to worry one of the million sensors on this dumb thing might be bad and me, with no diagnostic equipment (and no clue), would be buying sensors one by one, hoping to hit the jackpot. Crank shaft sensor, camshaft sensor, map sensor, tps sensor, dumbdriver sensor... on and on...
Then I stumbled across something that caught my eye. I read a post where someone said a Walbro pump should run absolutely quiet. If you hear any ticking noise from a Walbro, that means it's cavitating or sucking air. I remembered Chrismas night when my son was standing at my window while I thrashed my starter trying to raise the dead. He said, "what's that ticking noise?" I had checked, and it was from the pump, but I figured it was just a coincidence and ignored it at the time.
On connecting these two dots, I went down to the garage for a look see. There was a small puddle of diesel on the floor under my tank/pump area. I cycled the key to run the pump and, sure enough, the Walbro was making the slightest of ticking noises. More importantly, a few more drops of fuel fell to the floor. I looked underneath, expecting to find a loose hose around the pump, but all I could find was that the tank was wet on the outter side and the leak must be from somewhere up above.
I disconnected the fuel line from the input side of the stock fuel filter and put it in a bucket. Sure enough, when I cycled the pump, the fuel was coming in bubbly - almost foamy.
I'm no genius, but that couldn't be good. I made up reasons in my head why foamy fuel would create exactly the symptoms I had.
(continued next post... )
Last edited:
(still suspecting a failed VP - thinking it was probably caused by a bad comp box)
