Resolved: 94 2.3 Ranger TPS adjustment

Moe Szyslak · 08-07-2010, 08:33 AM

My ranger had the idle control unit changed a couple months ago. Since then it has not idled right. After taking it there 3more times I have lost faith in that shop. What they failed to notice was the vacuum hoses to the ECU where broken because of dry rot. I replaced this and now it idles very very low. I have also noticed that my gas mileage is worst since this started. I have reset the ECU numerous times. I think I need to reset the TPS since the shop set the sensor with no hoses to the ECU. My question is this, am I on the right track? How can I reset the TPS?

Dominick · 08-07-2010, 08:51 AM

Ford Fuel Injection » Throttle Position Sensor (TPS)

Dominick · 08-07-2010, 08:59 AM

The way I read it the TPS cannot be adjusted!
The Throttle Position (TP) sensor is a potentiometer that provides a signal to the PCM that is directly proportional to the throttle plate position. The TP sensor is mounted on the side of the throttle body and is connected to the throttle plate shaft. The TP sensor monitors throttle plate movement and position, and transmits an appropriate electrical signal to the PCM. These signals are used by the PCM to adjust the air/fuel mixture, spark timing and EGR operation according to engine load at idle, part throttle, or full throttle. The TPS is not adjustable.

Moe Szyslak · 08-07-2010, 09:24 AM

Where do I need to go?

Moe Szyslak · 08-07-2010, 09:36 AM

"The TPS should not need adjustment, but once the idle screw has been tampered with, the TPS should be adjusted to match. If the idle is low and the TPS is high lots of problems will appear. If you need to grossly modify the TPS mounting holes to adjust Closed Throttle between 0.6-1.0 volts, you should recheck the idle stop screw first"

I know that guy turned my idle screw to adjust the throttle in the 3 times I took it to him. Of course the vacuum hoses weren't hooked up to the PCM, I called this the ECU in my last post. My bad. What are the steps to get all this back to normal. With all hoses hooked up and brand new TPS.

Dominick · 08-07-2010, 10:32 AM

What Vacuum hoses are you talking about?
The ones on this Egr pressure regulator On the left or EGR vacuum regulator on the Right..
ECU or PCM don't have hoses as far as I know,

Skyhawk · 08-07-2010, 12:15 PM

The fully closed TPS should read approximately 0.6 volts when back probed. There is enough "play" in the mounting hole screws to get a slight "adjustment", but this is generally not necessary. The folks with 5 liter Mustangs do some "fine tuning" with the TPS, but it is generally not necessary in normal street aplications. At full open throttle the TPS should read approximately 4.5 volts. The throttle body idle set screw should NEVER have been touched. If the "mechanic" did "adjust" the idle and did not notice that there was a vacuum leak then find another mechanic to reset the idle.

Slartibartfast · 08-07-2010, 12:53 PM

that set screw for the throttle stop is to keep the throttle plate from closing completely. If the plate is allowed to close completely, it will bind giving a sticking throttle feeling. ECU/PCM doesn't have any hoses going to it. I'd recheck vacuum hose routing.

Ashzo77 · 08-07-2010, 04:02 PM

Originally Posted by Dominick

What Vacuum hoses are you talking about?
The ones on this Egr pressure regulator On the left or EGR vacuum regulator on the Right..
ECU or PCM don't have hoses as far as I know,

um... he said it was the the IAC valve... not Egr...

Dominick · 08-07-2010, 05:19 PM

I must be blind where does it say IAC?

Ashzo77 · 08-07-2010, 05:57 PM

Originally Posted by Moe Szyslak

My ranger had the idle control unit changed a couple months ago.

i could be wrong, but is that not the Idle Air Control?

Dominick · 08-07-2010, 06:06 PM

Yes that would be it

Just call me Stevie Wonder.
when he started talking vacuum my head went where the sun don't shine.

Moe Szyslak · 08-08-2010, 06:10 AM

Thanks to every one for the responses. I apologize for my lack of proper part terminology. Skyhawk said take it to a mechanic and he would be correct. However I'm on hear to see if I can save some money. Plus the satisfaction of knowing you fixed it. So is there any way I can reset the idle?

Moe Szyslak · 08-08-2010, 06:19 AM

Dominick, the dryrotted, not connected vacuum hoses were to the part on the left side of the pic you posted. There were not connected at all when the mech set the idle.

Dominick · 08-08-2010, 08:23 AM

Notice the 9e936 gasket between the 9e926 and the 9424
those will blow out and give you an idling problem.
on the 9e926 is probably where he did the adjusting.
I would disconnect the negative battery cable for a few minutes and the reconnect it and see if the computer will self set the idling.
I hope this helps

Moe Szyslak · 08-09-2010, 05:12 PM

I started looking at my vacuum hoses that I changed. See that hose. I knew that was the wrong hose for the job but used it anyways. Look at that pinch where it bends. Got the correct hose with a 90 degree bend. It is idling a lot better and driving a lot better. I just filled it up with gas and I will see if my MPG go up a little. Reminded me again to use the right part for the job. Sorry to waste your time guys. I did appreciate all of the responses. Thanks again guys.

Dominick · 08-09-2010, 05:38 PM

Thank you for the reply.
Glad you got it going!