Hi all,

I posted a few days ago and got some help and some education.

My truck was stuttering badly when warm and with any accelerator pedal was applied beyond what it takes to maintain speed on level road.

The scanner said misfire on cyl #8.
I didn't believe it (don't ask why) and convinced myself it was the EGR valve and its controls. (recent work on EGR pipes made me suspicious)

I dropped it back at my service guy's place, he replaced the plug wires and all was well for a couple days.

Today the check engine light pops on again.
Okay - my purchase of a OBD II reader is now going to come in handy.

"Code is PO122 TPS circuit low input"

I cleared the code and went about driving home.
after while it did it again - it seemed like the truck was hunting to figure out what gear to be in for second or two there and the CEL came on.
Same code.

I pulled the Throttle body cover off and got up close and personal with all those gizmos in that area.

The TPS looks pretty easy to replace.

Should I just replace it? Or do I need to test it out to make sure it is bad?

If I should just replace it - anyone have suggestions about a good place to buy a good one for a discount?


Oh and by the way - Last time I mentioned that there was some loud clicking going on in that area. I'm quite sure it was the Electronic Vacuum Regulator for the EGR valve. I say this because when I shut the truck down, I could hear it clicking again. It seemed like it was slowly bleeding down.

I tried it twice and the same thing happened. (no audible sound while engine is running, but the bleed down sound was there - and it sounded the same as what I reported last time when the engine WAS running.)

Is this little clicking bleed down sound normal?


Thanks in advance.
Scott

 

I think I tried to explain that to you in the last thread you started - CoilPacks, there weak - if you need a TPS , go ahead and get that at dealership / thirdparty - it doesn't matter , but you need one now. Before anything else and you can change that - That's an easy one - Two Screws after the TB housing/ shroud is off..

Replace Both Coil packs and you'll be good to go for another 100,000..

 

Oh - I fully plan to get a couple coil packs right away as you suggested.
I just didn't know if this TPS was related or not.

 

Not related - You need one ($50 @ Auto Zone )when my TPS went out It was upshifting /downshifting goofy as hell - I changed it ASAP - I didn't want it to over rev and screw the motor up - that's why I say to change that first , although , I don't know how bad your is acting - but anything can happen when those things go .

Another guy on this site had one go on him on the expressway in a Ford Windstar and blew the motor when it went into first fear doin about 70

 

Like a comedy of errors - only it isn't funny.

Replace the TPS - easy right?

Its never easy.

Ford dealership: TPS = $199 and they have to order it.
Autozone $36, and it is in stock.
Okay - I'll go the cheap route.

Remove two screws and the plug.
Screws won't budge.
I give them a squirt of penetrating oils stuff, and then go about removing a couple brackets and hoses that are in the way and keeping me from straight access and having a place to get some leverage.

No dice. I've even got vice grips holding the screwdriver handle for torque while I"m pushing axially with all I've got. Nope. No dice. The philips head cross slot is starting to deform too.

Maybe that's one of those damn posidrive screws?
Getting a posidrive bit doesn't help any.

F it! Good excuse to buy a tool.

Out comes the little cordless impact wrench.

The first one - which now has fairly deformed philips slots in it, comes out without much trouble. Why those screws are so buggered in there I don't know. Whatever the case - this screw isn't going back in there.

Second one - comes out and then make a run for it.
Down he dives into the arms of the aluminum octopus of known as the intake manifold.

A LONG time with flashlights, mirrors, magnets. No dice. Never found it.

My british cars are all inch standard. I have no stock of metric stuff.
So I'm off to the store to buy some 5mm screws. (actually hex headed this time so I don't have this problem again.)

The motorcraft TPS is without any doubt - a much studier piece of hardware. I wonder how long this cheapo aftermarket one will last?

On it goes.
Put the brackets and hoses back in place and go for a test drive.

It shifted weird a couple times before . . . not it is just plain old messed up.

Take off and rev up to about 3200 RPM, doesn't want to shift out of first.
I take my foot off the pedal completely and after a second it does go to the next gear. Further in the test drive, it is apparent that it doesn't want to downshift when I stomp on the gas either.

Damn it.

I didn't get any error codes or check engine lights though.
I guess I'll go back in there and make sure I actually have the TPS drive engaged correctly.

I'd have thought they'd have idiot proofed that thing so you can't put it on wrong.

Maybe I'm just a higher caliber of idiot than they planned on.

 

Global Automotive doesn't have my coil packs listed.
I send an e-mail - we'll see what he says.

There's a place called RockAuto that has them for a lot less than advanceauto too. Anyone know a reason not to patronize them?

 

LMFAO

When you started attacking those TPS and then your step by step decryption of what your going thru - I did the same exact thing per your description - " the trusty impact " buzzed them right off .

In fact I'll be doing that tomorrow .



Did you reboot your computer - you shouldn't ever work on these motors with the battery connected and when mess with anything that has to do with the way she runs , you always reboot so your PCM will relearn the trans tables , fuel trim and eventually your misfire monitor. The truck should run on all eight when you reboot .

It will re-calibrate and as long as your within default set parameters - it should run very well from get go when driven in normal fashion.

What's the part # on the TPS you just bought ?

Holy Crap!!! $ 199 was the dealership price !! NO , that must be the installed price or something . Hang on , I look it up..

Dealership Price =

Throttle Position Sensor
. F4SZ9B989AA
. $63.24

So , you were quoted very wrong .. - Make sure you have the right Part # above..


Global doesn't have them - Idunno , that were most go for COP's , I thought he prolly sold the packs to - Let me know how much they are - I 'll see if Kevin can get them for yuh when your ready..

 

No I didn't. But that makes sense.
I was reading a little last night, and all my dippy Haynes manual said was that if I checked the signal at closed throttle, it should be between 0 and .5V and at WOT it should be betwen 4v and 5v

That's a significant range. I mean - The new TPS could be working fine, but just not have identical values, and so the computer is trying to run with the output range of the old TPS.

http://www.partsamerica.com/productd...pe=280&PTSet=A
super cheap. (as in cheaply made) Doesn't inspire confidence.



Thanks, I'll check another dealership as well as recalling that dealership.
$63 is much more reasonable. And seeing how well the motorcraft one was made, I'd consider spending the extra money on it. I might keep the other one and see if I can adapt it to my old Triumph.

I'm ready to buy immediately.
rockauto is $83 each
https://www.rockauto.com/dbphp/prt,48,DG457


Thanks for taking the time to help me out jbrew.

 

So there WAS a CEL on with the TPS code (P0122) this morning when I started it up.
Not sure why it didn’t come on while I was driving last night.

I did reboot as Jbrew suggested before driving to work today.

Is there a different way to do this besides disconnecting the battery?
(gotta set the clock and all the radio presets now)


Darned if RockAuto doesn’t have motorcraft TPS for $36.79
MOTORCRAFT Part # DY967 {#F4SZ9B989AA}
F4SF-9B989AA

That is low enough that it makes me suspicious – is it really Motorcraft? Is it really new?

 

Have either of you tried adjusting your TPS?Yours by design are not adjustable but there is a way to make it adjustable.It may be worth a try first instead of buying a new one.I can't say for sure if it would help if it is real weak though.

 

-

Pull #24 - One row over to the right - count 5 up from the bottom - That's your PCM fuse. (Green Maxi Thirty) Pulling that will reboot .

If your working on the motor , always disconnect your Neg off the battery

 

Okay - so it appears that as I drive down the road, the CEL will not come on. It is certainly shifting very weird. Holds low gears too long even after I let off the gas, and its hard to make it downshift to a lower gear when I try to accelerate from a moderate speed (30 to 45mph)


Sounds like TPS doesn't it?

After I shut the truck off, and then go start it up again, then the CEL will come on and give me the P0122 code again.

I've pulled both TPS off - the new cheapo one and the original Motorcraft one.

When we put a meter up to them, the both behave roughly the same.
Slightly different min and max numbers, but when we do the math assuming a 5volt input, the output voltage at fully closed and fully open thottle fall within the values the haynes manual I have says it should be.

I've also checked that the TPS is actually getting a nice 5 volts from the trucks wiring harness.

So now I don't know what the heck to do.

What should I do?
Should I try to find where the TPS signal goes back to the PCM and see if it is seeing the correct voltages there at closed and WOT?



BTW - Global Automotive wrote me back and said they should have my coil packs next week.

Scott

 

Somethings not right here -

It has to be the sensor.

Remember what Kevin said awhile ago - did you try that ? Never mess with the gear yourself by turning it with your finger - You can adjust very little by loosening the TPS screws enough to reposition - not much movement there really - maybe like a 1/4 " up or down .

Mine doesn't adjust - some do...


What a minute - You did replace this correct ? I'm assuming your having problems with a new one now. This ones new right?


This is a new sensor , correct?. You peplaced it right ?. I just never seen anyone have so much problems with this sensor - it's usually pretty staight forward. It goes bad - you replace it ....

 

You have 2 right?Take one of them and drill it out They are usually unadjustable because of their stupid bushings.Get a drill bit and start drilling.Do not go any bigger than the size of the bushing though.After that you have tons of room for adjustment.It is a pain to get it where you want it.I can't remember the open position but the reading for closed throttle is .98
The closer you can get to that the better.You need a good digital voltmeter and don't go by the haynes manual for which wires to probe because i think its wrong.There is a how to in the lightning forum somewhere for more info.It may be worth a try.I dunno the new one should work fine though
You want between .95 - .98 and not exceed 1.00 optimium is .98 closed throttle
I didn't know this was a common failure part
this should get ya started! https://www.f150online.com/forums/sh...abolt+throttle

 

I now have three TPS units.

The original 1997 Motorcraft one with 95K miles.
The cheapo aftermaket one
A brand new Motorcraft one.

The truck drives the same with all of them.

I haven't had the new motorcraft one on the bench to test.
But I did do a fair amount of checking with the other two with my brother's fancy Fluke meter.

One of them I took to work and hooked up to a variable output powersupply.
Dialed it up to 5 volts, ran it through its range of motion, and got good values at both ends of the travel.

Whatever the case, I don't believe it is a matter of putting the TPS is the "right" position. I understand the concept of what you are saying, but there's just no way that kind of stuff is necessary to make these things work.

In short - I don't believe it is the actual sensor.

I know I've got 5.05V coming in to the sensor at the connector.

I haven't actually MEASURED the signal coming out of the TPS on the truck.
I guess I should figure out how to do that. I'm really not too confident about my ability to "BACK PROBE" the conductors in the TPS connector though.

If I could measure that . . . and it came out to be okay, then the last thing I could do would be to find where that signal goes to the PCM and see if it is making it all the way down there.

I really don't want to take it to the dealership for an @ss reaming my the wallet. I'm about to run out of options though.

(I'm sure as hell not taking it to the one that told me the TPS was $199 thou)

I'll try again tomorrow.

The weather is nice, so I can drive the old Triumph until I sort this stuff out.

Thanks for your comments.
Scott