View Full Version : worked theTPS and still no OD
03-08-2003, 08:27 PM
I'm still trying to get OD to come in with heavy throttle. <br>Tonight, I tried several different TPS settings al lthe way down to .340 volts. NOTHING CHANGED.<br>The truck still went into OD at 35 mph with light throttle and you can hold the throttle down for days and it'll run up to 70 mph but not hit OD. Not gonna do it. <br>The voltage increase with throttle movement is smoth and linear. It's stopping between 3.0 and 3.7 volts at WOT. The number varies accordingly with the base setting. <br><br>I'm getting ready to hack into the wires and run a second ground to a switch so I can fire it off manually. <br>The power rolls off pretty quick after 60 mph. If I could get it to hit OD at that point, I'd be really happy.
03-08-2003, 08:45 PM
Have you checked and/or adjusted the trans throttle cable?
03-08-2003, 09:05 PM
this is the same thing im having with my 93 throtle all the way down and wont shift to overdrive 70 mph just stays there! then u back off and it will shift. it never did this before i had my injector pump redone and put back on and a new throtle cable. so i messed around with the trans cable and i got it to work for about a week and that was it cant get her to shift! i havent messed with the tps yet. sounds just like ur prob!
03-08-2003, 10:57 PM
Certain model lock out OD when over 3/4 throttle to minimize slippage. Try taking out TPS stub and fixing voltage at 1.3 volts. I have driven that way for 12 years.
03-09-2003, 10:29 PM
Sootblower<br><br>can you please explain this procedure? I've never heard of that! What is TPS stub and how is that done?<br><br>thanx<br>brad
03-09-2003, 10:34 PM
".....Certain model lock out OD when over 3/4 throttle to minimize slippage..."
Mine didn't do that, neither stock nor after the upgrade...
Try adjusting the TV cable, but make sure you mark it's current position, and only adjust a slight amount either way.
The manual calls for .180" gap at the rear of the slotted part... between the firewall end of the cable and the attaching post in the slot. You can use a 1/8" drill bit to check your current setting.
There is a little lock tab on the cable right were it attaches to the throttle bracket assembly. Hold the TC cable in position, lift the lock tab, move the slotted end of the TV cable a small amount, and relock the tab. Drive it and see if that helps.
After that, you may have a governor valve or pressure leak problem internally, but that's just a guesstimate...
03-09-2003, 11:53 PM
BlownDodGE: I got my service manual out to double check what I said about 3/4 throttle and could not find it. I remember reading it 12 years ago in one of my manuals. What I did find is the following is required to get the 3 to 4 OD shift:<br><br>1) speed sensor and TPS voltage determine shift point. 1.3 V is actually about 37 mph up-shift on mine and it has to go back to 32 mph to down-shift ( 5 mph deadband). WOT on TPS is 3.5 volts and causes shift at about 60 mph. 2) coolant temp switch must be closed (above 50 degF, memory?) 3) transmission fluid thermoswitch must be closed (below 273 DegF, known) <br><br>To answer your question about bypassing the TPS: If you remove it you get 0.0 volts and computer inhibits shift. If you just "fix" the position of the TPS physically by making it look like 10% throttle, the computer is fooled into shifting at 37 mph regardless of throttle. That is the way I have been driving mine, as it used to shift like a yo-yo in the mountains here. The torque converter is so loose I can go up most grades in fourth. To fix the voltage do the following: 1) remove TPS screws (qty 2) 2) remove small plastic stub with the stainless bolt that is underneath 3) cut a small piece of sheet metal with two holes(for mounting screws) that lies flat under the TPS. Use tin snips to cut a small tab that can be bent up to fit in the bottom TPS slot that fixes voltage at 1.3 volts.<br><br>Just beware that this is for 91 to 93 only and at your risk. There is no lock-up TC clutch in these trannys that is hydraulically applied like the 95+ 47RH/E. Mine has 240,000 km with no problems. The 3/4 clutch pack is actually spring applied in the OD compounder, so pressure does not seem to be an issue at low speeds. The transmission governor hydraulic pressure goes up, with throttle and vehicle speed via that TVC cable, to all other clutch packs and bands to minimize slippage with increasing torque demand.<br><br>At very least you can bypass TPS just to verify your problem and then decide to leave it or buy the $200 part.<br><br>Hope this helps out. Please let us know.
03-10-2003, 12:22 AM
Hey Sootblower do you still have that TPS stub that you say you took out? I broke mine and i'm trying to look for a replacement. The dealer wants $575 for the bracket, TPS, and a new Stub as you call it. If you do still have it i would like to take it off your hands.<br><br>Chris
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