Tps ?

Just wondering how commonly the TPS go out on an obs truck, i have an idle issue and a throttle flutter lie 5 seconds after start up and im wondering if it is a tps issue.

I found this... Hopefully it helps you...

You can test the TPS :You need to put a voltmeter across the GY/W and the GY/R wires on the connector to the TPS. With the key on, watch the voltage across the range of the throttle to see if there is any flat spots. You should see no less than .37 volts at idle position and no more than 4.5 volts at full throttle. The the third wire, (BRN/W), is the ref. voltage and should be 5 volts all the time.

ok thanks hopefully i'll find time tomorrow to check it out

Maybe if you describe your issue a little more, we can get a better idea of how to approach it...

Well basically I have an real rough idle and it sounds like the truck is trying to shake itself apart, or has a miss, it will go away and smoothen up once i touch the pedal and give it some fuel(minimum of 700 rpms to smoothen out) and when I fire up the truck it will idle smooth for about 5 seconds then go right to the choppy idle and pick up a few hundred RPMs.

Sounds like the IDM going into limp mode .. May have a bad injector solenoid

I swapped out the IDM already with a known good IDM, in trying to follow codes that i was told were found when i bought the truck, i know i could use a new main engine harness due to the current one on the truck being spliced together.

Just unplug the TPS...


It's not the TPS. But completely unplug it and fire the truck up. When nothing changes, you can avoid wasting anymore time on it.

Deereman4020 said:

I swapped out the IDM already with a known good IDM, in trying to follow codes that i was told were found when i bought the truck, i know i could use a new main engine harness due to the current one on the truck being spliced together.

Click to expand...

You can test the injector solenoids if you are up to it ,


On each valve cover connection there are five pins. The outermost pins (pins 1 & 5) are for the glowplugs. They should not have continuity with each other or the center three. The center three are for two of the injectors in each bank. The ohm reading between each outermost injector(pins 2 & 4) and the center pin (pin 3) should be about 3.2 ohms (if I remember correctly. Pins 2 & 4 should also not have continuity with each other.

You can try this as well, start the truck in neutral and see if the truck idles normally without touching the throttle. My truck had a sparatic idle on start up all the time and even starting in neutral. But I replaced my Transmission Range Selector and my sparatic idle on startup went away.

95powersmoker said:

I found this... Hopefully it helps you...

You can test the TPS :You need to put a voltmeter across the GY/W and the GY/R wires on the connector to the TPS. With the key on, watch the voltage across the range of the throttle to see if there is any flat spots. You should see no less than .37 volts at idle position and no more than 4.5 volts at full throttle. The the third wire, (BRN/W), is the ref. voltage and should be 5 volts all the time.

Click to expand...

Old thread... but this helped me diagnose my TPS. Thanks!

Even a cheap scanner can give you TPS readings, in percentage (0-100%) if not voltage.