Attention: TDR Forum Junkies Ladies and Gentlemen,
My 2002 QC 4x4 HO truck has 154,000 miles on it. Injection pump replaced under warranty at 98,000 miles along with the APPS sensor. Dealer said LP was OK but I had that changed out on my own nickle by local Cummins dealer. Truck at that time would occasionally go to where I had no throttle response. I do a lot of highway driving and would normally happen when I would kick the cruise off to slow down going through some town. Condition would last anywhere from 5-60 seconds and then everything would work again fine. Anyway had above parts replaced and everything has been fine for the last year. Friday I had the dreaded no throttle condition return while pulling an empty 18' utility trailer for about 5 seconds. It was such a short time that I was not even sure that was what had happened.
My truck is completely stock. I get out my Briar Hopper fuel gauge yesterday and check my fuel pressure. They seem fine for a minute or two at idle and then drop of to 1-2 lbs. I check my fittings at the injection pump where gauge is attached and everything appears fine. I fire it back up and readings are good for a minute or two and then drop again. Check trouble codes and had got P1693 and P0216. I was 1000 miles away from normal fuel filter change ( which I do every 10,000 miles) so I go ahead and change out filter. Fire her back up and everything appears normal. Take a short ride down the road and get the following readings:
13. 5 - 14 at Idle
11 @ 2000 rpm 0 MPH
10 @ 2000rpm and 70 MPH
8 - 8. 5 under hard acceleration through the gears.
Readings appear to be maybe a little lower than when I first had VP-44 and LP changed out, but fuel filter appears to have solved problem.
Visual examination of filter does not look any different than any of the other 15 times it has been changed.
I go out this morning to drive to town and have around 13 at idle and around 10 running down the highway at 60-65mph. I don't remember if I was running the cruise control or not but after 15 miles of everything running OK I come to a stop sign and my pressure drops off to 1-2 psi. I turn it off restart the engine and pressures come back OK. Make a couple of more stop signs and pressure drops to 0-2 psi. Turn it off restart and pressure returns to normal for a couple of minutes or so and then drops. This happens five or six times and I turn around to head home to get another vehicle. I run a stretch of about 15 miles with the cruise control on and pressures stay fine. I disengage the cruise to make a left turn toward my hous and pressure drops to 0-2 psi. Pull over stop, restart and pressure returns to normal and I make it home.
My other observation while the pressures drop the engine continues to run fine with no hesitation, stumbling, dieing, etc. If I had not been watching the fuel pressure gauge taped to my windshield I would have had no indications of any problem.
My questions are:
1. Is my VP-44 going ?
2. Is my LP going ?
3. Why does it run fine with the cruise on?
4. Why does stopping and restarting the engine bring back the pressure?
( This makes it appear to me to possibly be an electrical problem with the pump)
Any thoughts would be appreciated as local dealer has not impressed me with their knowledge.
Sorry for such a long post,
Thanks,
James
My 2002 QC 4x4 HO truck has 154,000 miles on it. Injection pump replaced under warranty at 98,000 miles along with the APPS sensor. Dealer said LP was OK but I had that changed out on my own nickle by local Cummins dealer. Truck at that time would occasionally go to where I had no throttle response. I do a lot of highway driving and would normally happen when I would kick the cruise off to slow down going through some town. Condition would last anywhere from 5-60 seconds and then everything would work again fine. Anyway had above parts replaced and everything has been fine for the last year. Friday I had the dreaded no throttle condition return while pulling an empty 18' utility trailer for about 5 seconds. It was such a short time that I was not even sure that was what had happened.
My truck is completely stock. I get out my Briar Hopper fuel gauge yesterday and check my fuel pressure. They seem fine for a minute or two at idle and then drop of to 1-2 lbs. I check my fittings at the injection pump where gauge is attached and everything appears fine. I fire it back up and readings are good for a minute or two and then drop again. Check trouble codes and had got P1693 and P0216. I was 1000 miles away from normal fuel filter change ( which I do every 10,000 miles) so I go ahead and change out filter. Fire her back up and everything appears normal. Take a short ride down the road and get the following readings:
13. 5 - 14 at Idle
11 @ 2000 rpm 0 MPH
10 @ 2000rpm and 70 MPH
8 - 8. 5 under hard acceleration through the gears.
Readings appear to be maybe a little lower than when I first had VP-44 and LP changed out, but fuel filter appears to have solved problem.
Visual examination of filter does not look any different than any of the other 15 times it has been changed.
I go out this morning to drive to town and have around 13 at idle and around 10 running down the highway at 60-65mph. I don't remember if I was running the cruise control or not but after 15 miles of everything running OK I come to a stop sign and my pressure drops off to 1-2 psi. I turn it off restart the engine and pressures come back OK. Make a couple of more stop signs and pressure drops to 0-2 psi. Turn it off restart and pressure returns to normal for a couple of minutes or so and then drops. This happens five or six times and I turn around to head home to get another vehicle. I run a stretch of about 15 miles with the cruise control on and pressures stay fine. I disengage the cruise to make a left turn toward my hous and pressure drops to 0-2 psi. Pull over stop, restart and pressure returns to normal and I make it home.
My other observation while the pressures drop the engine continues to run fine with no hesitation, stumbling, dieing, etc. If I had not been watching the fuel pressure gauge taped to my windshield I would have had no indications of any problem.
My questions are:
1. Is my VP-44 going ?
2. Is my LP going ?
3. Why does it run fine with the cruise on?
4. Why does stopping and restarting the engine bring back the pressure?
( This makes it appear to me to possibly be an electrical problem with the pump)
Any thoughts would be appreciated as local dealer has not impressed me with their knowledge.
Sorry for such a long post,
Thanks,
James
