4r100 potential power issue
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Tuned
Joined: Mar 2018
Posts: 346
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4r100 potential power issue
Hey all, haven't posted here much but am more of a frequent knowledge thief of the forum. Know, ive run into a question I cant seem to solve by lurking.
My 2001 Excursion 7.3/4r100 has about 210k on the clock and runs like a deer, except when towing heavy or even unloaded on steep mountain grades.
The symptoms that I think are strange occur when driving in these conditions, ill be approaching a grade at 50-70 mph and begin to apply pressure to the accelerator to 'spool' the turbo and get revs up in order to keep speed and conquer the hill with ease. The motor however does not audibly increase rpm or fuel flow (as in the turbo/boost does not come up to speed) until the 4r100 downshifts to 2nd and quickly thereafter 3rd.
This almost seems like the accelerator pedal and the computer arent 'talking' properly and the trans steps in to downshift and boost rpms.
Now, in my gasoline vehicles I would consider this normal, as the motor runs out of HP for the job in a given gear, the trans picks up the slack.
Additionally, when in the same conditions and Cruise Control is set, things seem to be operating 'normal' in my opinion. As grades approach, you can hear the motor noise/intake/exhaust growl, the rpms stay relatively constant around 2k, and the seat of pants power is VERY noticeably increased. While all this is going on, the trans has not downshifted.
Do I have a problem somewhere in my manual driving system or is this a figment of my imagination?
Engine modifications as follows:
6037 filter, stock intake tube/egr
Wicked Wheel II with gtp38 stock turbo, fresh rebuild
Stock Intercooler/boots, recently cleaned and tightened everything.
MBRP 4'' turbo-back exhaust
Hutch/Harpoon mods
Dark Blue CPS
EBPV Delete with garret housing & non-ebpv pedestal
285/75 All Terrains, stock trans
My 2001 Excursion 7.3/4r100 has about 210k on the clock and runs like a deer, except when towing heavy or even unloaded on steep mountain grades.
The symptoms that I think are strange occur when driving in these conditions, ill be approaching a grade at 50-70 mph and begin to apply pressure to the accelerator to 'spool' the turbo and get revs up in order to keep speed and conquer the hill with ease. The motor however does not audibly increase rpm or fuel flow (as in the turbo/boost does not come up to speed) until the 4r100 downshifts to 2nd and quickly thereafter 3rd.
This almost seems like the accelerator pedal and the computer arent 'talking' properly and the trans steps in to downshift and boost rpms.
Now, in my gasoline vehicles I would consider this normal, as the motor runs out of HP for the job in a given gear, the trans picks up the slack.
Additionally, when in the same conditions and Cruise Control is set, things seem to be operating 'normal' in my opinion. As grades approach, you can hear the motor noise/intake/exhaust growl, the rpms stay relatively constant around 2k, and the seat of pants power is VERY noticeably increased. While all this is going on, the trans has not downshifted.
Do I have a problem somewhere in my manual driving system or is this a figment of my imagination?
Engine modifications as follows:
6037 filter, stock intake tube/egr
Wicked Wheel II with gtp38 stock turbo, fresh rebuild
Stock Intercooler/boots, recently cleaned and tightened everything.
MBRP 4'' turbo-back exhaust
Hutch/Harpoon mods
Dark Blue CPS
EBPV Delete with garret housing & non-ebpv pedestal
285/75 All Terrains, stock trans
FTE Chapter Leader
Joined: Nov 2010
Posts: 30,593
Likes: 1,236
From: N. IL
Hey all, haven't posted here much but am more of a frequent knowledge thief of the forum. Know, ive run into a question I cant seem to solve by lurking.
My 2001 Excursion 7.3/4r100 has about 210k on the clock and runs like a deer, except when towing heavy or even unloaded on steep mountain grades.
The symptoms that I think are strange occur when driving in these conditions, ill be approaching a grade at 50-70 mph and begin to apply pressure to the accelerator to 'spool' the turbo and get revs up in order to keep speed and conquer the hill with ease. The motor however does not audibly increase rpm or fuel flow (as in the turbo/boost does not come up to speed) until the 4r100 downshifts to 2nd and quickly thereafter 3rd.
My 2001 Excursion 7.3/4r100 has about 210k on the clock and runs like a deer, except when towing heavy or even unloaded on steep mountain grades.
The symptoms that I think are strange occur when driving in these conditions, ill be approaching a grade at 50-70 mph and begin to apply pressure to the accelerator to 'spool' the turbo and get revs up in order to keep speed and conquer the hill with ease. The motor however does not audibly increase rpm or fuel flow (as in the turbo/boost does not come up to speed) until the 4r100 downshifts to 2nd and quickly thereafter 3rd.
I like to downshift the V10 manually, before a long, steep grade; the tranny rarely gets the downshift timing perfect before losing speed, part way up the hill.
Cross-Country
Joined: Aug 2015
Posts: 82
Likes: 1
The difference in performance between driving manually and driving with the cruise control set makes me wonder if your throttle position sensor is going out.
Do you have a code scanner or a Bluetooth OBDII dongle and Torque or Dash Command? If so you can use it to monitor the output of your throttle position sensor. There's probably alternative ways of checking it as well.
Do you have a code scanner or a Bluetooth OBDII dongle and Torque or Dash Command? If so you can use it to monitor the output of your throttle position sensor. There's probably alternative ways of checking it as well.
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