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manual trans TPS to ATX throttle body-it works

40K views 34 replies 13 participants last post by  amc49 
#1 · (Edited)
My 2000 zetec ATX wagon started having idle troubles, kept dying and erratic behavior down around idle. No CEL. New IAC stopped it for a little bit then it came back.

Bought a 2000 manual TPS since everyone states new ATX one not available. Bought a washer and two sheet metal screws too at $.69 and 2X $.19. ground a flat on the washer to clear the bumpout on the TPS and then drilled two screw holes in the outside edge of washer to match mounting holes on TB. Put the washer on top of the TPS flat and screwed them both down to TB using the longer screws after grinding off the screw hole bosses on the TPS. The bosses prevent the TPS from swinging in a circle. Now the TPS is 360 degree adjustable under the washer, I swung it to get .90 volts at idle stop and 4.62 volts at wide open throttle using a voltmeter and the center white wire on TPS connector. Tighten the screws down there, the washer holds the TPS firmly in place. Be cool, over tightening I'm sure could crush the TPS, it only has to be tight enough so that sensor will not budge trying to move it by hand. My washer was 1/8" thick, it did not warp at tightening. No additional connector needed either, the connection is identical.

Pull battery cable off, back on, relearn idle for 10 minutes and now the idle problem is gone. The trans shifts perfectly including kickdowns at proper speeds, and engine power is fine.

Comparing the MTX TPS and the ATX one shows them as having the same total range swing, it's just that one starts and ends up in a slightly different place from the other, thus affecting the whole range, if you make the one part have the same starting point as the other then no difference at all.

As with other things, no way was I buying a new TB, mine was in excellent shape but for the TPS. Easiest $100+ I ever made.

All of you who were doing this incorrectly simply indexed the manual TPS in wrong as it doesn't match the ATX mounting point, the index is maybe 5-10 degrees off, which gets you into the off idle point of the TPS and screws up the rest of the range.
 
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#2 ·
Excellent "work around" on this parts unavailable problem for those who are mechanically inclined!

Detail how the test meter was hooked up for the electrically challenged, and this should be a "sticky" since I doubt the 'automatic" TPS will become avail. again....

As a bonus, it details how to test one for proper function if you add "checking for smooth change in voltage between extremes" to the "test" & "adjust" description.

Kudo's!
 
#4 ·
Yeah - pics would be great. I got a lower mileage TB in "The Box" also. Swapping stuff out before trouble appears.

OEM parts on the older cars are beginning to show up as NLA. Fuel injectors are 'no longer available' from the dealer on the 2000. Not sure how different 2000's are different from later years.
 
#5 · (Edited)
Yellow wire is VREF or 5 volts, white is TPS output, the 3rd brown wire thinking, well it's a ground at PCM. Power runs from yellow to brown or a power loop from the PCM, the TPS output shorts a variable part of that out to be read by PCM also. You read with KOEO, turn key till indicator lights come on. Problem is getting inside the connector to connect up without damaging it. I found some extremely small wire off a cheap radio, it had only one wire strand inside it. Bared about 2 inches and worked it inside the connector so it was trapped and most likely pinched by the middle pin or white wire when connector snapped together. Use red VOM plus lead on the other end of that and a convenient ground for other black VOM lead. THe yellow VREF can be checked for 5 volts with KOEO and connector disconnected, easy to get inside it then. Plus on the yellow wire and grounded black again.

My factory ATX TPS was not spring loaded one way, the manual one is, that affects nothing.

From everything I've seen, you must make the idle point slightly under one volt even. I started at .40, but have seen some postings showing the early models have trouble with 'insufficient TPS volts' codes that low, plus the upper wide open throttle volts are supposedly supposed to be around 4.84, I was at 4.10 or so. Moved it to get max close to one volt, or the .90 figure mentioned and the wide open moved to 4.62, close enough and it worked fine. It does not have to be exactly the same number, just under one volt and the high up past 4.50 I'm thinking, the PCM has an algorithm to refigure the real world volts when you leave the battery cable off to force relearn. As mentioned it must have very smooth voltage increase through the entire swing, the TB was physically off and just lying on intake so easy enough to check that then.

'Bout time too, I was really getting tired of having to manually forcefeed idle speed to that pig of a car.
 
#15 · (Edited)
Not to sound ungrateful, this is a very helpful mod, but there are several things I am just not understanding:

If the mechanicals for the ATX TPS and the MTX TPS are the same - just internally clocked differently, why don't the parts companies sell an ATX TPS? It seems like there are probably more ATX Focuses in the world having the failure.

EDIT: After more research, I can probably answer this myself now.
  • Pre-2003, MTX and ATX used the same TPS Connector plug, but part was clocked differently. Not a good idea as you can't look at the parts and tell what you have, and you could install the MTX on an ATX car or vice-versa and not know why it didn't work.
  • 2003, the ATX got a different connector, but the MTX was the same.
  • Makes sense to continue making the MTX part as it can be used before or after 2003.
  • However, it doesn't make sense to continue making the 2000-2002 part as those are the only years that use it. Solution is either to modify the MTX part as above, or modify the ATX harness (maybe) and use the newer ATX TPS.




I'm having a hard time getting my head around how this mod works. You said earlier the mod provided 360-degrees of rotation. 4doorFRRIBTR who did the mod and posted the pictures said he had 15-20 degrees of rotation.

Looking at the picture it looks like the mod didn't change anything except the TPS is bolted down from the top instead of the bottom.

I don't see really how there is any play in the TPS except maybe 5-degrees before the connector hits the washer.

I could see if the washer were ground with the flat closer to the center (say even with the bottom of the inner hole), you could get close to 120-degress of rotation.

Or if the holes in the washer were slotted, but that would be hard to plan and do in a home shop ...

What am I missing?
 
#16 · (Edited)
Also - doing some digging on RockAuto ...

I can get a TPS for a 2003 ATX for $34.79. The connector is different, but seems to be the same pin type and shape, just a different shield shape and the 2003 connector is $17.61.

Wouldn't it be an easier (although more expensive) repair to just de-pin and re-pin the two connectors, or worst case, cut and splice the 2003 connector into the 2002 harness?

EDIT - From the other thread, 2003 TPS needs 2003 TB and connector, so no, this won't work.
 
#17 ·
That pic is not mine, mine HAD the washer flat cut more toward the center to have some swing. By 360 degrees I meant the outside case with the screw bosses cut off. It helps to clarify understanding that the outer body can twist some. It actually does NOT swing the full 360, the bolts get in the way. All it needs to swing is maybe 15 degrees max.

Say the TPS, either one, has a clock swing of 20 degrees. One though, begins at 12:00 straight up and the other begins at 1:00. Remove the screw tabs and then both TPS become the same part.

Look at aftermarket TBs, they have multiple TPS bolt-on patterns, including slightly different ones for ATX and MTX. That is what convinced me the idea would work. Mine still runs fine. The TPS case DOES move slightly, enough that the existent bolt holes no longer work. Slotting holes would work but not enough material left to be dependable in my view. The pic there shows that the switch case has been moved slightly CCW, his washer is becoming the limiting factor there, mine had more room to rotate but not needed. It doesn't take much, enough that it is hard to see it but the engine and trans sure do.
 
#18 ·
That pic is not mine, mine HAD the washer flat cut more toward the center to have some swing. By 360 degrees I meant the outside case with the screw bosses cut off. It helps to clarify understanding that the outer body can twist some. It actually does NOT swing the full 360, the bolts get in the way. All it needs to swing is maybe 15 degrees max.
Makes sense to me now!!!

Look at aftermarket TBs, they have multiple TPS bolt-on patterns, including slightly different ones for ATX and MTX.
My Google-image-fu failed me, but I'll take your word on this and I found some other text references to this.

The TPS case DOES move slightly, enough that the existent bolt holes no longer work.
You lost me here. The existing bolt holes in the washer no longer work? The existing bolt holes in the TB no longer work? (If the latter, what is holding it on now?)

Thanks again!
 
#19 ·
I think amc's meaning is that the different types of TPS move the holes a bit (clocked differently) just enough that slotting the holes wouldn't work as a way to adapt the different units.
 
#20 ·
Okay, I've got it now.

I was talking earlier about slotting the holes on the washer and thought amc49 was referring to that. I also thought amc49 meant that the throttle body holes on his car were no longer working.

Re-reading it again carefully, amc49 (I think) is saying that it would work to slot the holes on the TPS to align it, but not enough material left for the screws to hold it, so he came up with the idea of cutting the bolt holes off and using the washer.

Makes sense now.
 
#22 · (Edited)
The MTX TPS is not a problem, either type works.

Another Ford engineer driven issue that didn't need to be. The TPS come in all forms and fashion but pretty much all use the same operating voltages, meaning they could have made many more of them interchange over various TBs than they did. More corporate 'protection' by changing every part every 10 minutes.............
 
#23 ·
I'm out of town so I can't do any conversions. But the one listed for my car physically doesn't fit, it's too small overall and too flat all the ones listed for my car. The one listed for ATX looks correct but the little teeth in the center are incorrect.

Sent from my SM-G920T1 using Tapatalk
 
#25 ·
The one on the left is the later '03 type one. Confusing though because some Fords use that case type on much earlier cars, my '98 Contour and '88 Tempo use it.
 
#27 · (Edited)
You need to get out more.....................my '02 has one and OEM. The '00 has the other one, both cars have factory uncut and unpatched with different connector harnesses. Both zetecs and in my case both ATX. The TB shaft ends are different too. More Ford goofiness.
 
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