TPS question

[kyleag89]

Ok so my truck is acting like the tps is bad. (Bad idle and tranny not shifting right) I got one from the JY and adjusted it to specs and checked operation. It checked out ok but I do have my idle screw out a little. Would having the idle screw turned up effect the tps adjustment?

[88pioneer]

could be the tps, or a cracked vacuum line. The line from my map sensor cracked and it ran pretty bad

[Oizarod115]

Ok so my truck is acting like the tps is bad. (Bad idle and tranny not shifting right) I got one from the JY and adjusted it to specs and checked operation. It checked out ok but I do have my idle screw out a little. Would having the idle screw turned up effect the tps adjustment?

if you adjusted the TPS with the idle screw in its current location then the tps adjustment is good.

you need to set the base idle with the screw, then adjust the TPS to its happy place after it idles right.

 

most likely there was another problem causing the bad idle and you've got the screw covering up the problem.

check all the vacuum lines

[Harper]

What engine are you talking about, because if you're talking about the Renix 4.0, there is no "idle screw". The idle RPM is controlled by the ECU's manipulation of the idle speed actuator. The only (correct) purpose of the screw is to not allow the throttle plate close so far as to bind in the throttle body throat. The throttle plate should be virtually closed at idle.

[Oizarod115]

What engine are you talking about, because if you're talking about the Renix 4.0, there is no "idle screw". The idle RPM is controlled by the ECU's manipulation of the idle speed actuator. The only (correct) purpose of the screw is to not allow the throttle plate close so far as to bind in the throttle body throat. The throttle plate should be virtually closed at idle.

renix does have an idle screw you're not really supposed to move it but its there, and it is adjustable if needed.

[Harper]

What engine are you talking about, because if you're talking about the Renix 4.0, there is no "idle screw". The idle RPM is controlled by the ECU's manipulation of the idle speed actuator. The only (correct) purpose of the screw is to not allow the throttle plate close so far as to bind in the throttle body throat. The throttle plate should be virtually closed at idle.

renix does have an idle screw you're not really supposed to move it but its there, and it is adjustable if needed.

 

 

I know the screw is there. My point is that it is not an idle screw! To use it as such could well screw things up. If you have to use it to "set" an idle, you've got other problems that you are ignoring, and are treating the symptom and not the cause.

[kyleag89]

Well my truck will idle at 700RPM and when you hit the gas from a stop it will idle down to 100RPM and then take off.. If it doesn't stall first. All my vaccum lines are new, would the IAC cause this? I would say MAP but it runs fine once you are moving, its just that initial start from a red light.

[Harper]

Hard to say what it might be, but diagnosing the sensors with a digital auto-ranging multimeter would be my suggestion. I doubt it's the IAC, since once you've applied the accelerator pedal, the IAC's no longer in play. Also check and clean all the fuel system electrical connectors. They are a common source of problems with age. Also check EGR system.