Strange 7.5 problem
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Junior User
Joined: Dec 2006
Posts: 51
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Strange 7.5 problem
I just came back from a 2,000 mile road trip in my RV. It has a 1995 F Super duty chassis and drivetrain with a 7.5 gas burner. While on the trip I encountered a very strange driveability issue that has me puzzled completely.
Here are the symptoms:
-Drives fine from start-up for around 25 or so miles.
-after that it begins to act "strangled" when trying to pull hard up a hill, but only if you have to kick it down out of OD to pull the hill
-First it will begin losing power, then it will begin popping back through the intake until you start losing more and more power and eventually have to limp over to the shoulder and turn it off. For a while it will run fine as long as you stay in high gear and below about 2200 rpm.
-The trick is, all you have to do is cut it off and then about five minutes later, crank it up and you can drive like nothing was ever wrong with it.....until about another 20-25 miles and you have to do the process all over again.
-once I got tired of pulling off and shutting down, the next time it started sputtering, i figured out that I could simply shift to neutral, turn the engine off, crank it right back up and it would run fine for a few more miles....then i just repeat the process.....its almost like it "re-boots" the computer or something.
Here is what I have done for diagnosis:
-2 new tanks of good gas with sea foam added in
-replaced ICM, ignition control module
-replaced coil
-already has new plugs, wires, cap, and rotor
-has new fuel pump and filter
-unplugged o2 sensor to see if symptoms changes
-ran diagnostic codes and retrieved the following in KOEO mode:
-172-lean exhaust left bank
-212-loss of IDM signal
the KOER check was fine with the standard 111 code being the only thing that showed.
Those codes lead me to do replace the Module and the coil and also to unplug the o2 sensor but no luck.
Its something weird that may be in wiring or something but it strikes me as very odd that you can switch it off and back on and then it runs good again. I am thinking I may have a fried computer and the switch on and off "re-boots" it.
Sorry for the long post but I wanted to be thorough with this. Hope some of you have some ideas.
Josh
Anyone have any ex
Here are the symptoms:
-Drives fine from start-up for around 25 or so miles.
-after that it begins to act "strangled" when trying to pull hard up a hill, but only if you have to kick it down out of OD to pull the hill
-First it will begin losing power, then it will begin popping back through the intake until you start losing more and more power and eventually have to limp over to the shoulder and turn it off. For a while it will run fine as long as you stay in high gear and below about 2200 rpm.
-The trick is, all you have to do is cut it off and then about five minutes later, crank it up and you can drive like nothing was ever wrong with it.....until about another 20-25 miles and you have to do the process all over again.
-once I got tired of pulling off and shutting down, the next time it started sputtering, i figured out that I could simply shift to neutral, turn the engine off, crank it right back up and it would run fine for a few more miles....then i just repeat the process.....its almost like it "re-boots" the computer or something.
Here is what I have done for diagnosis:
-2 new tanks of good gas with sea foam added in
-replaced ICM, ignition control module
-replaced coil
-already has new plugs, wires, cap, and rotor
-has new fuel pump and filter
-unplugged o2 sensor to see if symptoms changes
-ran diagnostic codes and retrieved the following in KOEO mode:
-172-lean exhaust left bank
-212-loss of IDM signal
the KOER check was fine with the standard 111 code being the only thing that showed.
Those codes lead me to do replace the Module and the coil and also to unplug the o2 sensor but no luck.
Its something weird that may be in wiring or something but it strikes me as very odd that you can switch it off and back on and then it runs good again. I am thinking I may have a fried computer and the switch on and off "re-boots" it.
Sorry for the long post but I wanted to be thorough with this. Hope some of you have some ideas.
Josh
Anyone have any ex
Thread Starter
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Junior User
Joined: Dec 2006
Posts: 51
Likes: 0
Is there any way the fuel pressure would just drop off after running for a period of time and then just go back to normal when I shut it off and then turn it right back on again? I guess I could plug a pressure gauge up and watch it while I drive down the road....
