# 88 D21 Throttle Position Sensor questions



## dafoedoe (Oct 27, 2007)

Greetings,

This is my first post so please bear with me. I have been searching for days and cannot seem to find an answer to this question.

I have a 88 D21 4 cylinder pickup which has been giving me acceleration problems for a little while now. It starts up without any issues, but when you get on the gas, it starts cutting out / hesitating. It does not matter if the engine is warm or cold. I used to wrench on cars and think it can only be a bad TPS or possible ignitor problem.

Does anyone have any information on how to test the TPS for functionality (ie. ohm or voltage test under wide open throttle or closed?)

I have already performed the following ECU test and the red LED does not turn on when the pedal is depressed:

Mode IV - Switch Operation Monitor
Use Mode IV to determine if the Throttle Position Sensor (TPS), Starter circuit and/or Vehicle Speed Sensor (VSS) are in proper working order.
Turn the ignition switch on, but do not start the engine.
Turn the dial on the ECU fully clockwise. After the LED flashes 4 times, turn the dial fully counter clockwise.
Make sure the RED LED is turned off.
Make sure the RED LED turns on when depressing the gas pedal. If not, check or replace the Throttle Position Sensor.

If anyone knows, any help would be greatly appreciated.

Thank you in advance

Dan


----------



## zanegrey (Dec 5, 2005)

do a tune up first.
check coils .

also remove gas tank and check for fuel contamination

on reading the codes .

you are mixing years on the proceedure ( i think ).

reread the haynes manual..


----------



## dafoedoe (Oct 27, 2007)

*ITS FIXED!!!*

Thanks Zane, this is a trip. I seemed to have fixed the issue. Yesterday, I decided to unplug the TPS connectors and test resistance between the pins and couldn't get any info out of it. I got tired of testing it, then put it back together. To my amazement, my truck runs great now! I guess there was a bad connection somewhere in on of the TPS connectors. Thank you for your reply.

Dan


----------



## PerogyBoy (Oct 6, 2007)

FWIW, I have an 1987 SE V6 pickup. I had to have the TPS replaced for similar reasons.
there was 82365 Km on the vehicle at the time.


----------



## kmcarr (Sep 14, 2015)

I am having an issue with my 87 d21 pickup v6 4x4 TPS. I installed a new one, but it doesn't seem to work, now the truck won't start. Is there a procedure to adjust/install the tps for it to start working? wha tis the 82365 KM?


----------

