How to Disable RPM Match Feature

[mrm]

I recently purchased a 2000 Ford Ranger 2.5L with a 5 speed manual transmission. When I let off the gas to shift gears engine RPM does not drop as I am accustomed to on a manual tansmission vehicle. Engine braking is also not very good since engine RPM drops so slowly. From what I've read, this is some sort of "RPM Match" feature controlled by the ECM to aid in shifting gears.

Does anyone know of a way to disable this RPM match feature short of disconnecting the wiring to the Idle Air Control (IAC) valve or installing a solid gasket between the IAC and the throttle body? I would like to disable this feature in a manner that will not result in a malfunction code or turn on the check engine light.

Thanks for your help.

 

[NIPs]

Sorry but since its controled by the Ecu if its emissions related its gona send a cel, and I wouldn't disconnect the iac if I were u cuz the 12volt wire that runs that maf also runs the iac and fuel injectors so when u disconnect it ur gona open a massive can of worms

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[RonD]

Yes, RPM matching gives better MPG and also lower emissions.

Idle will stay at 1,000rpm until speed is below 5mph.

Outside of the 1,000rpms, which is cold engine idle as well, engine braking should be about the same, yes a little slower in happening, lol.

And no, as said above, no way to disable it

 

[gw33gp]

I am pretty sure that feature is primarily emissions related and has little to do with shifting. It can be disabled but you have to reflash the computer with a program that disables it. Or if you know how to reprogram, you can do it yourself but it sounds like that is not something you know about and neither do I.

My Ranger has a program that disables the 'throttle hang' feature among other performance enhancements. There is a considerable difference in engine braking with and without it. I think shifting is easier with that feature disabled. The rpms drop quicker and shifting can be done quicker. Although, I do think the drivetrain is exposed to less shock when transitioning back and forth from acceleration and deceleration with the stock program.

I reprogram the computer back to stock when I have the truck smogged. I drive it that way for a couple week to let the ECU get accustomed to the change. I can't wait to get it back to the performance program because it is so much better to drive and not just because it has better performance.

Those reprogrammers are not cheap so you may decide you can deal with the 'throttle hang' feature. I am also guessing that your computer is reprogrammable, I know my 02 4.0 SOHC is.

 

[tomw]

Is it possible the IAC is gummed up, and just slow to return to the commanded position? I have had that happen. Cleaning can sometimes make it return to better operation.
My understanding of the engine braking operation was that fuel flow from the injectors was interrupted when the throttle plate was closed at higher than idle rpms. Back when, one emissions control mechanism was a delay valve using vacuum that prevented the throttle plate from snapping fully closed when you took your foot off the gas. Felt like you were driving with rubber bands connected to the throttle as it reacted differently depending on 'things' modifying results of your pedal movement.
If is has OBD-II I'd think you can look at the IAC command to determine if it is ECM ordered or is just hanging.
tom

 

[mrm]

gw33gp, Can you tell me about the reporgrammer you have - where do you get one and the cost. What kind of performance enhancements will it do?

Thanks.

 

[NIPs]

Flashing the pcm would b the best way but chances are ur truck was taken to the dealer once in it life time for whatever reason and when it was there they flashed it then, the dealer flashes ur vehicle when it comes in for simple oil change and u as the customer would never know, what I suggest clean iac throttle body and plate, intake manifold if u can, maf and all that may change it may not, I live in state where we don't smog test, huge plus cops are laxed we can do whatever

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[gw33gp]

The programmer I have is SCT and was programmed by BAMA. They are up to X-Cal 3 versions now I think. The important thing is not to use just standard programs. You need to get it from a programmer that really knows what they are doing and request certain features. Bama doesn't program Rangers anymore but there are companies that do. Just do a search for SCT X-Cal programmers. I have heard company called Henson Performance does custom tunes with X-Cal 3 tuners but I have not dealt with them.

I don't know what the current cost is but I would guess if you buy the X-Cal tuner from the company that tunes it, it would be in the range of $400 to $600.

I gained improved acceleration. That is not just seat of pants rated. I timed with a stop watch from 40 to 70 mph and 50 to 80 mph in third gear. I have three different tunes; 87 octane performance, 91 octane torque and 91 octane performance. They all showed improved acceleration but the 91 Torque program showed the most improvement. Compared to stock the 91 Torque program had an improvement of 0.7 second 40 to 70 and 1.2 second 50 to 80.

I also have a slight improvement in gas mileage (5 - 10%) with the performance programs when I drive without using the extra power.

My program also increased the speed limiter above the normal 92 mph. I have never reached the limit but I think it is somewhere between 100 and 110 mph. I didn't have the rev limiter changed.

When I am accelerating full throttle and taking it to high rpm and shifting quickly, I don't have that normal slight hesitation when grabbing the next gear and flooring it again. There may be some other performance enhancements but I can't think of any right now. I know with an automatic transmission they can change the shift points and firm up the shifts.

 

[adsm08]

Flashing the pcm would b the best way but chances are ur truck was taken to the dealer once in it life time for whatever reason and when it was there they flashed it then, the dealer flashes ur vehicle when it comes in for simple oil change and u as the customer would never know

This makes no sense to me on any level.

Just because a vehicle comes into a dealer's shop does not automatically mean we waste the half hour to hook up an IDS and update the software in the PCM for no reason at all. In fact, unless there are specific instructions in a TSB or FSA to update the software on a module Ford highly discourages the practice.

Also, being programmed once does not prevent an EEC-V computer from being programmed again, and again, and again. It is EPROM storage, which can be written and re-written to as many times as you like, if the right equipment is available, it's not a frickin CD-R that is one and done.

 

[ricardo93]

Can eec-iv be flashed over an over or just once or not at all?

 

[NIPs]

I meant if their was tsb I thought that was kinda of obvious

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