Attention: TDR Forum Junkies 
Hey guys, I have a new to me truck with some issues and I need some advice. The truck is a 03 3500 4x4 automatic with 298,700 miles on it, it's bone stock as far as I know. I bought it about 3 weeks ago and have put around 800 miles on it since then. I'm at least the 3rd owner, the guy I bought it from bought it from a used car lot about a year ago, so no one knows much about the history of repairs.I'm a diesel mechanic by training, but haven't worked in the field or kept up with changes for about the last 15 years or so. I'll go into what I know/see about the truck and then into what problems it's having.
The truck has an aftermarket electric fuel pump (PPE) mounted on the frame rail and a remote mount filter just after the pump. The line that went to the original pump/filter housing inlet has been cut and a new hose ran from the outlet of the remote mount filter directly to the CP3. It looks like the original lift pump quit and instead of replacing it, they just plumbed in a new electric pump and filter, bypassing the factory filter housing. The steel line coming out of the CP3 goes to a banjo fitting on the front of the factory filter housing and then into the rail. From what I can see, the only line that has been modified is the line from the tank/aftermarket pump/remote filter straight to the CP3.
When I first got the truck, it idled normal but would surge under load (about 30-50 mph going up a hill), as if it was running out of fuel. It never stalled or smoked during this. I changed the fuel filter, added a dose of grey power service, and drove it for a day or two, no change. I read that the FCA was probably the culprit, as they're a common problem. I took the FCA off and cleaned it with carb cleaner, once I did this I could hear the plunger rattling inside of it when I would shake it, where as before I cleaned it I didn't hear the rattle. I put the FCA back on, , the surge was gone for about a day, then came back twice during the next drive, and then disappeared again. It hasn't done the surging anymore since then in about 450 miles.
The next thing that happened was a random slight miss/pop sound from the exhaust at idle speed. When the miss/pop would happen I would see a slight puff of greyish smoke from the tail pipe. Anything above idle speed the truck seems to run normal, normal power, no smoke, and seems to run smooth. I didn't know when the last time the valves were adjusted was, so I did that. Most were in spec, but one exhaust valve was way loose, probably in the .080 range. I adjusted them all, setting the intakes at .006 and the exhaust at .026. Setting the valves didn't seem to change much, it sounds a little smoother overall, but the miss/pop at idle was still there.
About a week later (probably 250 miles) the random miss/pop at idle has become constant. The smoke has increased to a sort of haze that's visible but not really "clouding out the parking lot". It still runs fine above idle, no codes, normal power, and seems smooth. The fuel mileage over the last 663 miles is 15.4 average, consisting of about 60% city driving and no towing. It hasn't stalled at idle or been hard to start during any of this and seems to be the same whether the engine is hot or cold. During the last day or two, it seems like it shuts off slower than normal. In other words, you turn the key off and now it takes 3 or 4 seconds for the engine to completely die..... when you turn the key off it seems to slow down to 500 rpm, then 400, then 300, and gradually die rather than a crisp shut off like normal.
Looking around on the internet, the consensus seems to be injectors. But I'm wondering if the FCA could possibly cause this too? I know it was having issues when I bought the truck and cleaning them isn't a good fix..... Suppose the FCA is stuck again but in a "higher fuel pressure" spot this time, would it cause these issues? Also, with the fuel lines plumbed the way they are, would that cause any problems? I have an inexpensive code reader that shows some data, but not anything too valuable in this case. It only shows codes, ECT, IAT, TP, and MAP readings.
Also, not sure if it's related to the previous problems or not, but the fuel gauge acts weird. The day I bought the truck, the previous owner told me that he had just filled the tank but the fuel gauge didn't always work. He said it would work for a while, then not work for a while, but if you hit a bump just right it would start working again. It wasn't working at all the day I got the truck. I unplugged the connector from the top of the tank, it was very dirty, and cleaned it. As soon as I did that the gauge started working but showed 1/4 tank. A few hours and 5 starts later, the gauge showed 1/2 tank. A few more starts later it showed 3/4 tank. A few starts later it showed Full and worked normally for the past couple weeks up until today. I actually have about 7/8 of a tank of fuel in the truck, but this evening when I started it, it shows half a tank again.
Any help or advice you guys can give would be much appreciated!
The truck has an aftermarket electric fuel pump (PPE) mounted on the frame rail and a remote mount filter just after the pump. The line that went to the original pump/filter housing inlet has been cut and a new hose ran from the outlet of the remote mount filter directly to the CP3. It looks like the original lift pump quit and instead of replacing it, they just plumbed in a new electric pump and filter, bypassing the factory filter housing. The steel line coming out of the CP3 goes to a banjo fitting on the front of the factory filter housing and then into the rail. From what I can see, the only line that has been modified is the line from the tank/aftermarket pump/remote filter straight to the CP3.
When I first got the truck, it idled normal but would surge under load (about 30-50 mph going up a hill), as if it was running out of fuel. It never stalled or smoked during this. I changed the fuel filter, added a dose of grey power service, and drove it for a day or two, no change. I read that the FCA was probably the culprit, as they're a common problem. I took the FCA off and cleaned it with carb cleaner, once I did this I could hear the plunger rattling inside of it when I would shake it, where as before I cleaned it I didn't hear the rattle. I put the FCA back on, , the surge was gone for about a day, then came back twice during the next drive, and then disappeared again. It hasn't done the surging anymore since then in about 450 miles.
The next thing that happened was a random slight miss/pop sound from the exhaust at idle speed. When the miss/pop would happen I would see a slight puff of greyish smoke from the tail pipe. Anything above idle speed the truck seems to run normal, normal power, no smoke, and seems to run smooth. I didn't know when the last time the valves were adjusted was, so I did that. Most were in spec, but one exhaust valve was way loose, probably in the .080 range. I adjusted them all, setting the intakes at .006 and the exhaust at .026. Setting the valves didn't seem to change much, it sounds a little smoother overall, but the miss/pop at idle was still there.
About a week later (probably 250 miles) the random miss/pop at idle has become constant. The smoke has increased to a sort of haze that's visible but not really "clouding out the parking lot". It still runs fine above idle, no codes, normal power, and seems smooth. The fuel mileage over the last 663 miles is 15.4 average, consisting of about 60% city driving and no towing. It hasn't stalled at idle or been hard to start during any of this and seems to be the same whether the engine is hot or cold. During the last day or two, it seems like it shuts off slower than normal. In other words, you turn the key off and now it takes 3 or 4 seconds for the engine to completely die..... when you turn the key off it seems to slow down to 500 rpm, then 400, then 300, and gradually die rather than a crisp shut off like normal.
Looking around on the internet, the consensus seems to be injectors. But I'm wondering if the FCA could possibly cause this too? I know it was having issues when I bought the truck and cleaning them isn't a good fix..... Suppose the FCA is stuck again but in a "higher fuel pressure" spot this time, would it cause these issues? Also, with the fuel lines plumbed the way they are, would that cause any problems? I have an inexpensive code reader that shows some data, but not anything too valuable in this case. It only shows codes, ECT, IAT, TP, and MAP readings.
Also, not sure if it's related to the previous problems or not, but the fuel gauge acts weird. The day I bought the truck, the previous owner told me that he had just filled the tank but the fuel gauge didn't always work. He said it would work for a while, then not work for a while, but if you hit a bump just right it would start working again. It wasn't working at all the day I got the truck. I unplugged the connector from the top of the tank, it was very dirty, and cleaned it. As soon as I did that the gauge started working but showed 1/4 tank. A few hours and 5 starts later, the gauge showed 1/2 tank. A few more starts later it showed 3/4 tank. A few starts later it showed Full and worked normally for the past couple weeks up until today. I actually have about 7/8 of a tank of fuel in the truck, but this evening when I started it, it shows half a tank again.
Any help or advice you guys can give would be much appreciated!
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