E4OD
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E4OD
So i bought a 1994 f150 4.9L inline 6 2wd E4OD Automatic about 6 months ago and everything has been great so far besides the occasional electric parts going out (like the disturber .etc ) but recently i put a six inch lift and 35s on it.But the other day i was driving around and noticed after it downshifted at around 60 or 55 mph it immediately put my rpms inbetween 1000 and 1500 rpms and makes a sound like its skipping or something and loses throttle response untill the pedal is almost half way down and jumps to 2000 rpms any ideas why this could be happening?
Lead Driver
Joined: Oct 2016
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From: Houston/Sugar Land
Not to hijack this thread but I put 265X75 on my 91 in place of the 235"s. Do I need to change the PSOM also and if so how? Edit So far no issues.
Lead Driver
Joined: Oct 2016
Posts: 6,185
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From: Houston/Sugar Land
Is this applicable to me and the original poster? From subford
Reprogram speed conversion constant using the following procedure:
-- Locate the dealer mode programming enable single-terminal connector.
The connector is located at the bottom of the instrument panel below the center of the glove box.
On all vehicles, the dealer mode enable wire is Circuit #567 (LB/Y) or 571 (BK/O) for early 1992.
-- Insert metal clip in service wire panel connector. Clip other end to vehicle ground while the key is in the OFF position.
-- Turn key to RUN (not crank) position while holding down the trip odometer RESET button on speedometer.
Release RESET button.
-- Speedometer will prove out (sweep across dial and back). The English/Metric and revision levels will be displayed.
The last number of the display is the dealer mode programming lockout count.
This count shows the number of allowable conversion constant changes remaining.
When the count is zero (0), no additional changes can be made to this instrument cluster.
-- Press and release RESET button again and PSOM conversion constant (without the decimal point) followed by the word CAL.
-- Press and release the odometer SELECT button as many times as necessary to change conversion constant to the correct value.
NOTE:Pressing and releasing the RESET button to lock in the new Conversion Constant reduces the number of times the PSOM can be
reprogrammed by one count.
The module can only be reprogrammed six times.
If you change your mind and want to go back to the old conversion constant, turn the ignition switch off before you lock in the new constant.
-- When the correct new value is displayed in odometer window, press and release the RESET button to lock in the new conversion constant.
-- Turn the key off and remove the ground wire. Verify proper speedometer operation.
Reprogram speed conversion constant using the following procedure:
-- Locate the dealer mode programming enable single-terminal connector.
The connector is located at the bottom of the instrument panel below the center of the glove box.
On all vehicles, the dealer mode enable wire is Circuit #567 (LB/Y) or 571 (BK/O) for early 1992.
-- Insert metal clip in service wire panel connector. Clip other end to vehicle ground while the key is in the OFF position.
-- Turn key to RUN (not crank) position while holding down the trip odometer RESET button on speedometer.
Release RESET button.
-- Speedometer will prove out (sweep across dial and back). The English/Metric and revision levels will be displayed.
The last number of the display is the dealer mode programming lockout count.
This count shows the number of allowable conversion constant changes remaining.
When the count is zero (0), no additional changes can be made to this instrument cluster.
-- Press and release RESET button again and PSOM conversion constant (without the decimal point) followed by the word CAL.
-- Press and release the odometer SELECT button as many times as necessary to change conversion constant to the correct value.
NOTE:Pressing and releasing the RESET button to lock in the new Conversion Constant reduces the number of times the PSOM can be
reprogrammed by one count.
The module can only be reprogrammed six times.
If you change your mind and want to go back to the old conversion constant, turn the ignition switch off before you lock in the new constant.
-- When the correct new value is displayed in odometer window, press and release the RESET button to lock in the new conversion constant.
-- Turn the key off and remove the ground wire. Verify proper speedometer operation.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
A 1991 model year truck does not have a PSOM. The computer gets the vehicle speed input from the VSS located at the transmission tailhousing. You would have to change the driven gear to get the speedometer to read correctly and send the corrected VSS output to the computer.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
A 1991 model year truck does not have a PSOM. The computer gets the vehicle speed input from the VSS located at the transmission tailhousing. You would have to change the driven gear to get the speedometer to read correctly and send the corrected VSS output to the computer.
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i have not and im in a tight spot and need something to change quick and dont really have money but im am doing a tranny filter and fluid change this week and im worried it has something to do with overdrive because when over drive is not on it doesnt do it
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Lead Driver
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Fleet Owner
Joined: Oct 2005
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From: Kentucky
The PSOM converts the raw VSS signal from the sensor located on top of the rear axle into a frequency range the computer can understand. The PSOM is physically located behind the Speedometer/Odometer. It needs to be updated to account for the much taller tires you installed. The computer is basing the shift points on the shorter tires.
Sandy posted the procedure in an earlier post. You need to find the revolutions per mile for those 35 inch tires to calculate the new PSOM calibration constant.
Some more PSOM info here: https://www.supermotors.net/registry/2742/69150-2
Sandy posted the procedure in an earlier post. You need to find the revolutions per mile for those 35 inch tires to calculate the new PSOM calibration constant.
Some more PSOM info here: https://www.supermotors.net/registry/2742/69150-2
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
The PSOM converts the raw VSS signal from the sensor located on top of the rear axle into a frequency range the computer can understand. The PSOM is physically located behind the Speedometer/Odometer. It needs to be updated to account for the much taller tires you installed. The computer is basing the shift points on the shorter tires.
Sandy posted the procedure in an earlier post. You need to find the revolutions per mile for those 35 inch tires to calculate the new PSOM calibration constant.
Some more PSOM info here: https://www.supermotors.net/registry/2742/69150-2
Sandy posted the procedure in an earlier post. You need to find the revolutions per mile for those 35 inch tires to calculate the new PSOM calibration constant.
Some more PSOM info here: https://www.supermotors.net/registry/2742/69150-2
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very so much it likes to downshift at 60-65 and hold between 1000 rpms and 1500 rpms and i get almost no throttle response until half way down and like i said earlier it sounds like its skipping or not firing on all 6 but i know it is bc i just replaced all my sparks and wires plus a disturber and rotor so i dont know at this point but it only does it when O/D is on