adjust your TPS (another free hp mod)

[james t]

i just checked my 94 xlt and the wiring for the TPS that worked for my reading is the far right wire(that would be your positive) and using the far left wire as my negative. now i got 4 volts just like husky, so i turned my down just as much as the screws would allow and it only moved to 3.99volts in order to reach the .96i would have to twist the TPS all the way around. not to sure this is for 1st generations can anyone help explain a little

Go back and read the first page. You were checking the wrong wire.

 

[Rhett]

ok you lost me for a second! IAC isn't the TPS?? or is that the cable thats plugged into it?

IAC and TPS are not the same. The TPS is attached to the side of the throttle body. The IAC is a cylindrical-shaped thing attached to the side of the upper intake manifold.

When you change the throttle body, and/or make any changes to it's butterfly screw, you need to make sure BOTH the TPS and the IAC are set correctly. Read the other thread, I told you how to test/set each one.

 

[kdogg212001]

what was the other thread again rhett??

 

[Rhett]

Your thread man!!!

http://www.explorerforum.com/forums/showthread.php?t=144254&page=2&pp=20

my post is #37, the post with the 3 things you should do:
1) make sure floored gas pedal opens the butterfly all the way
2) make sure truck idles at 500 rpm with IAC unplugged
3) see if TPS returns 0.96v

 

[tnmk]

Just did my TPS adjustment.
A little different for wire colors than what was posted. Maybe cause it's Mercury?
Gray/ red stripe= ground
Gray/white stripe = signal
Brown/white stripe = 5 V reference.

Didn't have to remove anything to get to it. right out in the open. Just needed a right angle screw driver.

Didn't slot the holes, just drilled 1/64" larger and it got me to the .96 Volts. Started at .91. I couldn't imagine having to go more than a 1/32 oversize to get your reading.

Now i'll see what diff it makes.

 

[EMG7895]

Another piece of the puzzle to add to the why .97 question. By doing this mod you are tricking the computer by making it think the butterfly is open 10 degrees.

 

[Turdle]

Another piece of the puzzle to add to the why .97 question. By doing this mod you are tricking the computer by making it think the butterfly is open 10 degrees.

Because it is open about 10 degrees at idle.
You think it is closed??

 

[EMG7895]

Because it is open about 10 degrees at idle.
You think it is closed??

I know that it is not completely closed, that is what the adjuster screw is for, so even if the screw has the angle more or less the computer will think 10 degrees.

 

[Fredness]

Ditto, the throttle is partially open when released. It is definately closer to 10* then it is 0*.

 

[gotbags?]

ill definantly try this

 

[Zero Signal]

Great writeup. I'll definitely give this a try this weekend while I'm doing my tune-up maintenance. Thanks for the tip!

 

[Apu]

OK, I have read this entire thread and I think this is what I am trying to figure out:

The TPS at .97 indicates 10% throttle to the computer which is the reference point for idle. Therefore, you must ensure that your throttle plate is at 10%. The idle must be set without the IAC connected at around 500 rpm for this to be true. After this is completed, check the TPS to make sure it is .96 - .97, if it isn't, adjust accordingly.

OR

The plate is set at 10% at the factory and that is why some mechanics say to never touch the screw unless you want a world of hurt. Technically, this would mean that the idle is not adjustable manually. The IAC adjusts the idle accordingly based on conditions. Using this logic, only the TPS should be adjusted and the idle screw should be left untouched.

 

[Pdwight]

Just checked mine

It was "Spot On" at .96 Volts with a Fluke Scope meter. I did change the fuel filter and it helped with the flat spot in the acceleration....it was after all the OEM one from 1993.

Dwight

 

[Zero Signal]

Your TPS may also be wired this way:

brown/white = +5VDC

grey/white = ground (common)

grey/red = TPS signal (~ 0.96VDC)

As you can see from the photo above, "tapping" the wires with a test probe leaves a nice little pin hole, exposing the conductor to moisture and oxidation. When you're finished with your readings, it's a good idea to wrap the wire with some electrical tape. Even a small dab of RTV will do the trick.... you just want something to keep the bare wire from being exposed to the elements.

 

[cgriffin_5139]

Make sure to put the new cover sheets on your TPS reports! :smoke:

James - awesome tip.

Riiight!

 

[Lazzman]

What type of volt meters are you using? I could not get the probes in the meter I have to break through the wire insulation. It is this Crappy GB unit I got at Sears for like $18.99

Should the probes be able to get through the insulation somewhat easily?

 

[Pdwight]

Funny

I have some Fluke "Wire Piercing " probes made just for jobs like this, ...but I just used two unfolded paper clips and slid them under the plug where the wire goes in....carefull to not let these touch two touch anything or chassis ground.

Dwight

 

[Runnin'OnEmpty]

You can also stick straight pins into the wires or back of the connectors, and take the readings off the pins. They leave smaller holes in the wire insulation than just about anything else.

 

[LeKid302]

The longest post i ever read about TPS !!

Merry Chrismas !!

 

[Mexplorer]

Ok, i guess i have to say something about this mod:

When i cleaned the Maf, the Explorer was more responsive, but not very powerful, some months ago. I changed Plugs and wires (to autolite platinums) and the truck felt more powerful, 160 good horses. I cleaned the IAC and the IAT sensor and the idle was good.

But now, with this mod, the truck feels with 160 very solid horses. I have to say, i tried first with the .980V setting and the truck feels better in highway than with .961V, which is actually the setting in the TPS. I have to second the argument about .980v, because at least in my truck the feel was very different, enough to appreciate.

A note; my truck had a very bad idle the first 5 seconds when starting in a cold morning. Now that problem is gone. I guess because the initial setting in my TPS was 1.010 volts.

Time to set the TPS....like 30 seconds, no drilling needed.
Time to remove the two phillips screws.....4 hours, yep, i have to behead those phuckers with a grinder very carefully, and i tried before with a bigger screwdriver, vise grips, etc etc, but at very least i didnt damage the TPS...

Tools needed
Digital Multimeter: 7 bucks
Vise grips: 6 bucks
4 new 7mm screws, now these are adjustable with a wrench.... .40 cents
My Explorer idling excellent in the cold mornings....priceless....

EDIT:

About the colors of the wires, all of them are different, but just try all the combinations (these arent much, there are only 3 wires...) and make yourself a favor, ground to the sensor, your reading will be more accurate.

I simply peeled a little the cables with a knife, and started to measure from that. Use electrical tape when you finish....