Throttle body

[kwats1928]

So my 2003 Ram 1500 with a 4.7 has been having a high idle, like around 1200. I cleaned the throttle body (it was nasty) and the ICV. It still idles high!!! After I cleaned the throttle body I can see light around the butterfly valve, is that normal? Any thoughts? Was told it could be the throttle position sensor, does this make sense? Thanks for the help.

 

[xb1230]

At 1200 rpm I would look for an intake leak.

Just do a quick google search on how to troubleshoot intake leaks and give it a go.

 

[User]

TPS can in fact cause this issue. The TPS relays information to the PCM regarding butterfly position, if the sensor is faulty or shorting out it can cause idle problems. Best solution is verify standard voltage from a TPS from a working same model vehicle and/or engineer schematics and verify with your TPS voltage, move forward with the compiled data from your test. IIRC, the 4.7 is a single blade front facing TB, what I don't remember is if it has the adjustable spring to open and close the blade as needed.

I also noticed that you mentioned an ICV sensor, I assume this is the same thing as a IAC (Idle Air control) sensor? From prior experience these are fragile sensors, and even after a good cleaning may still show intermittent issues.

I would start with verifying voltage from the TPS (throttle position sensor) and move on to the IAC/ICV sensor.

 

[kwats1928]

Sorry meant IAC, darn abbreviations. Thanks for the help I will try replacing the TPS first (its cheaper), after looking for vac leaks. It does have an adjustment screw out by where the throttle and cruise control cables attach. Should I mess with that? It takes one of those special star bits with the hole in the middle.

 

[User]

Sorry meant IAC, darn abbreviations. Thanks for the help I will try replacing the TPS first (its cheaper), after looking for vac leaks. It does have an adjustment screw out by where the throttle and cruise control cables attach. Should I mess with that? It takes one of those special star bits with the hole in the middle.

If you're familiar working with a multimeter, I would verify voltage on the TPS first before spending 40-50$ for a new sensor, you can rule it out and move on, while saving some money. Although, if you feel better just simply replacing the sensor, go for it.

The star bit, is called a torx measured with ~ T10, T25, etc. You can try loosening the adjustment screw to help close the blades, minute adjustments will be noticed, so adjust in small increments.

If needed, count the treads on the adjustment screw, or take a photo to help you remember exact location.

 

[HemiSLT]

DON'T touch the adjustment screw! If you mess with it then you will never get it right again. If you have a constant high idle and you don't have any vacuum leaks then I would lean way more towards a sticking IAC valve. If you were having a very choppy, fluctuating idle then I would say TPS. Good luck getting it fixed!

 

[kwats1928]

This torx has a piece in the middle so it would require like a hollow torx, is that a special tool? I am not sure of the voltages, any ideas where I would find them?

 

[xb1230]

When you have the bit in the middle of torx it is called a "Secured Torx" or "Security Torx". It is there especially so you don't mess around with it, which I would refrain against doing as these are adjusted from the factory.

What I am unsure of which I have just posted on, is whether or not the butterfly should be tightly closed at idles or not. I can see a few thou of an inch opening on mine which is also a 4.7L.

 

[xb1230]

Here are the voltage specs for my '02 TPS from the service manual :


DESCRIPTION
The 3–wire Throttle Position Sensor (TPS) is mounted on the throttle body and is connected to the throttle blade shaft.
OPERATION
The 3–wire TPS provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents the throttle blade position of the throttle body. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the output voltage of the TPS changes. The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from .26
volts at minimum throttle opening (idle), to 4.49 volts at wide open throttle. Along with inputs from other
sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing. The PCM needs to identify the actions and position of the throttle blade at all times. This information is needed to assist in performing the following calculations:
² Ignition timing advance
² Fuel injection pulse-width
² Idle (learned value or minimum TPS)
² Off-idle (0.06 volt)
² Wide Open Throttle (WOT) open loop (2.608 volts above learned idle voltage)
² Deceleration fuel lean out
² Fuel cutoff during cranking at WOT (2.608 volts above learned idle voltage)
² A/C WOT cutoff (certain automatic transmissions only)

I would suspect it is the same thing for '03 as the part numbers are exactly the same.

 

[User]

DON'T touch the adjustment screw! If you mess with it then you will never get it right again. If you have a constant high idle and you don't have any vacuum leaks then I would lean way more towards a sticking IAC valve. If you were having a very choppy, fluctuating idle then I would say TPS. Good luck getting it fixed!

Seems to be the exact opposite for me, vacuum leaks would make the idle choppy, for example low vacuum producing cams do not increase idle speed, but make idle choppy as if it's "weezing" for air. If vacuum levels are correct, and the IAC is stuck open it will cause a high idle, stuck closed would cause low rpm/dying issue, intermittent would be fluctuating RPMs.

TPS is a just a *****, period.

As for the adjustment screw, lol. Why call it an adjustment screw if you should never adjust it? If you follow the correct steps and reverse your steps, it is possible to find the correct adjustment location. Granted this should only be done when diagnostic is required, but I can see how it can be an issue with someone that would not pay attention to details.

This torx has a piece in the middle so it would require like a hollow torx, is that a special tool? I am not sure of the voltages, any ideas where I would find them?

EDIT: Disregard - Sounds like the general consensus is "do not mess with it."

 

[dmacell1]

I use those bits all the time for security reasons. Home Depot actually sells them.
If you are brave enough to mess with it...