long story short, working on a truck with running issues. missing doesn't want to idle, running rough. well i am getting code 63- tps below minimum or too low. came back immediately after three resets, so must be a problem. check reference, 5 volts. check output, 1 volt up to almost 5 seemed smooth. tried to check resistance, seems off but wasn't sure, ohms confuse me. so where do I go from here? what is the code telling me? the voltage is not making back to the computer? do I need to verify the voltage at the computer plug? does this code point to an open wire since the voltage is right at the connector? any help appreciated!! I figured I need to fix this code before I go looking for more problems. also I was running the truck, check engine light came on, seemed to run a little better when the light came on. pulled code and 63 was the only one.

thanks!! chris

 

Did the idle problems and rough running just start or did you adjust something and then problems. Are you getting erratic idle speed then won't idle? If code 63 and problems just started, the code is telling you that most likely your TPS is sick. When you check continuity, set scale to 5k ohms, then when you move the throttle note that resistance smoothly goes down. The green should be neg and black pos, should be 3-4k ohms with throttle closed and approx. 350 ohms at full open.
Fuel Injection Technical Library » Throttle Position Sensor (TPS) this site will give you a good bit of info on checking TPS out.

 

I am working on this for an older friend of mine so details are a little lacking. all I know is he said it started missing and not wanting to idle. I went to look at it, and it would idle and run down the road but but had a part throttle miss and felt funny running hard, maybe like a shudder? anyway I was thinking fuel so I checked the filter but didn't have a gauge. drove it some more and the miss got worse and the idle was rough. well I left and was coming back in a few days with a fuel pressure gauge. he drove it again a ways to some where then to some where else. he left there and said it barely made it home. wouldn't idle wouldn't hardly go down the road, check engine light on. go look at it again, verify good fuel pressure, changed plugs and cap, also cleaned the iac last time. truck starts but will not idle, will die. the idle is high and unsteady, like the computer is trying to get if to idle. I checked codes and find 63. checked the tps sensor all looks good. reset codes run it again 63 comes back. I pulled battery cable and tried it again. 63 comes back, and I noticed when the check engine light came on the sound of the engine changed a little. when you start it now the whole engine is rocking when you rev it and it is not happy, and will not idle on its own. not sure if I am getting an ignition miss or fuel mix problem. I am not sure where it go from here but figure fixing code 63 is the first step. can the voltage be right and the ohms check not? if the voltage is right at the sensor connector, do I need to check the wire for proper voltage at the computer connector? could it be in the signal return wire? I would expect other sensor problems if the return wire had issues. so basically I need help with this code 63 before I go hunt other problems. sorry for the long post, only way I could explain it.

thanks!! Chris

 

Yes, ref volts can be good & resistance bad, that says bad TPS. Your description of problem is reinforcing that.

 

So I am reading the 1 volt to 4.whatever on the green and black. It goes smoothly as expected. But the ohms could still be wrong and the sensor bad even though the voltage being sent to the computer is right? I will try to get back over there and check it again.

Thanks!! Chris

 

ok, new thought. since I am getting code 63 in the second set of codes, which is continuous memory, doses that mean the fault is intermittent? if the sensor was reading low all the time, the koeo would detect if and throw the code out? but since it is in cm, that must mean it is happening while it is running and not a hard fault, correct? any thoughts?

later!! Chris

 

This illustrates why we need to know when a code is displayed. Code 63 from CM does indicate the error is intermittent while the vehicle is in operation.

 

It would also be nice to know the year and the engine size.

DH94 CONTINUOUS MEMORY CODE 63: MONITOR TP CIRCUIT UNDER SIMULATED ROAD SHOCK

Enter Key On Engine Off Continuous Monitor mode.
Observe VOM for indication of a fault while performing the following:
-- Move throttle slowly to WOT position.
-- Release throttle slowly to closed position.
-- Lightly tap on TP sensor (simulate road shock).
-- Wiggle TP harness connector.
Does VOM indicate a fault?


Yes
INSPECT connectors. If connectors and terminals are good, REPLACE TP sensor.

 

Well if anybody is interested, it was the tps sensor. Watched the voltage while the motor was running and it was jumping around. Replaced it and truck runs good and the voltage is now steady. Amazing how much havoc this sensor raised and it was not clearly bad. And also foud a large vaccum line i must of knocked loose. Lesson learned and filed away for future use... Thanks everbody!!! Chris

 

Thanks for the feedback.

 

X2 thanks for the feedback