hello, i have a 1994 accord dx 4 door with an issue. i've been trying to track down a shifting issue- basically the car will go up and down the gears with no issue. it only has a problem when you decelerate from a higher speed, then accelerate (without coming to a stop). at this point, it frequently jumps in rpms, like it goes into overdrive, so slippage or anything.. . anyways, i was told to check the map sensor and the TPS by a transmission guy. i switched out the map sensor last week, and, surprise, there was no change. fast forward to the other day, and i put a new throttle position sensor in, and that's where new problems begin.

i got a TPS from standard motor parts, and basically, for it to be calibrated at 0.5 v at closed throttle, the open throttle will only reach 3.5 volts-- when i've been told that it must be 0.5 volts closed, and 4.5volts open. ok. so i try and start my car. it starts, but i can't shift out of gear, the shift interlock suddenly doesn't allow me to. ok, so i adjust the lower voltage to about 0.7 volts. this allows me to start the car, and shift out of gear, but it dies immediately when i do so. and yes, i allow it to relearn the idle, but that doesn't help.

that's my problem.
oh, and there are no trouble codes to be found.

is a 1994 accord dx really supposed to be 0.5 volts closed, and 4.5 volts open? is there a way to increase this spread? i tried opening the idle screw, as someone told me that will affect the lower voltage, but it had no affect. Also, i tested my last TPS before i took it off the car to find it at 1.25 volts closed. When i saw this, i intially thought i might be onto solving a problem, but nope. the exact opposite. Anyways... any help offered would be very much appreciated. and thank you for your time.

 

The shop manual says that the TPS should be 0.5V at closed throttle at 4.5V at open throttle.

The TPS sensor should be keyed where it is rotated by the throttle body. I think the key looks like the letter T, but I can't remember exactly.

Make sure that you got that key inserted into the throttle body correctly.

Also, check that your volt meter is working properly. Check that it reads around 12.6V across a fully charged battery. The voltage between the yel/blu and grn/blu on the unplugged TPS connector should read 5V.

 

yup, i've checked and rechecked that it is inserted correctly.
and i've done the check with the voltmeter as you've described.
yet, if it is calibrated to .5volt, closed throttle, the shift lock won't allow me to shift out of park. if i up it to the .7-.8 range the shift lock allows shifting out of park.

but heyyy, update... i replaced the map sensor a week prior- well, i put the old one back on, and it stays running now, lol. so that is a huge improvement.

now just back to the calibration...
is there any way to increase the range of voltage of the TPS? regardless of where i calibrate the low end, the high end will only be approximately 3 volts greater- not 4. also, what effect does the voltage of the tps (at low, and high range) ultimately have? say, for example, what change in performance would a vehicle have that has a tps calibrated to .5v closed throttle, 3.5 volts open throttle, versus a tps calibrated to 1.5 volt closed throttle, 4.5 volt open throttle?