[oh2swapped]

Well its going on 3 weeks of having my throttle body and plenum installed and it sticks at 1500 rpm's until I come to a full and complete stop. The guy at Ford said its because I took off the TPS and didn't line it up correctly because it runs off of micropulses or something along that line...Is this true before I take it to Ford to have it fixed??

[silvergtstang99]

you can do it yourself you did it before. Take it apart and clean it, put it back properly

[oh2swapped]

Alright i didn't know they said they needed to hook up a voltmeter to it. If that was the case my buddys a service writer at Ford so I get all the work done for free..

[00silvergt]

technically the TPS in our cars are non adjustable, but you can take a a drill and 'oval' out the holes in the TPS sensor so you can adjust it. I am thinking your problem is something else...

[00silvergt]

I ovalled out my TPS sensor so I could adjust it with a voltmeter, but all it really did was give me quicker throttle response

[oh2swapped]

alright, well then any other ideas its kinda getting annoying lol

[00silvergt]

maybe your speed sensor located in the transmission. your computer uses that so it knows your RPM vs the speed of your car. Just an idea, but you said it started when you added the plenum and TB, so maybe someone else will chime in.

[silvergtstang99]

What kind of Throttlebody/plenum did you buy. I hear BBKs stick.
Mine stuck for a day or two, ever since then its been 100% fine.



try this?! clean the maf and filter too.
Problem starting my car (won't idle)

[oh2swapped]

C&L plenum and i dont know what TB i bought it off of a guy at the track....

[silvergtstang99]

What does it say on the actual TB. For example the stock one had the pony running.

Maybe your throttle cable isnt 100% right. Cheap, worn down part, maybe needs cleaning. It could be a few things.

[cliffyk]

"Adjusting" the TPS on a EEC-V engine will accomplish nothing as the PCM constantly reads the TPS ouput and saves the lowest value it sees as the closed throttle value.

Since it knows the angular rate of the potentiometer that is the TPS it can calculate the throttle position at any time using the known rate of change, current output voltage, and saved "closed" throttle voltage.

Returning to the OP's idle problems, the "hanging" idle until the vehicle stops is normal however it's normally only at 1000 to 1100 rpm. 1500 is high. The reason for this is to ensure adequate power steering fluid pressure for the power brakes.

Have you tried disconnecting the battery for 5 -7 minutes? Doing so will clear the KAM (Keep Alive Memory) which is where the PCM stores learned values like the idle air trim, used as a reference for all idle control functions. Resetting the KAM will force it to relearn these values.

This is from the shop manual and may be of assistance:

Idle Speed Control Closed Throttle Determination One of the fundamental criteria for entering rpm control is an indication of closed throttle. Throttle mode is always calculated to the lowest learned throttle position (TP) voltage seen since engine start. This lowest learned value is called "ratch," since the software acts like a one-way ratch. The ratch value (voltage) is displayed as the TPREL PID. The ratch value is relearned after every engine start. Ratch will learn the lowest, steady TP voltage seen after the engine starts. In some cases, ratch can learn higher values of TP. The time to learn the higher values is significantly longer than the time to learn the lower values. The brakes must also be applied to learn the longer values. All PCM functions are done using this ratch voltage, including idle speed control. The PCM goes into closed throttle mode when the TP voltage is at the ratch (TPREL PID) value. Increase in TP voltage, normally less than 0.05 volts, will put the PCM in part throttle mode. Throttle mode can be viewed by looking at the TP MODE PID. With the throttle closed, the PID must read C/T (closed throttle). Slightly corrupt values of ratch can prevent the PCM from entering closed throttle mode. An incorrect part throttle indication at idle will prevent entry into closed throttle rpm control, and could result in a high idle. Ratch can be corrupted by a throttle position sensor or circuit that "drops out" or is noisy, or by loose/worn throttle plates that close tight during a decel and spring back at a normal engine vacuum [emphasis added].

[steve_stang2003]

Originally Posted by cliffyk "Adjusting" the TPS on a EEC-V engine will accomplish nothing as the PCM constantly reads the TPS ouput and saves the lowest value it sees as the closed throttle value.

Cliff is correct.

FWIW I went through this with an Accufab 70mm combo on my 2003 automatic and eventually ended up sending it back because the idle hang drove the automatic tranny crazy when coming to a stop.
Sort of like stepping on the gas and brake at the same time.
My car is complete stock except for a Magnaflow catback.

I found out later that this is a very common problem and that their is a parameter called "return to idle" or something like that which can be changed via a tune and will solve the problem.
For the record, everything was installed fine on my car, no leaks, no binds, reset the KAM etc

Some cars just have this problem and others do not.
Some cars fix themselves after a week or so of driving, mine did not.
Automatics seem to be more prone to this from what I can tell so I suspect maybe it's related to firmware in the PCM being different on various cars.
I don't know.