Throttle position sensor...

 

How do I test it? If it's bad, do I need to get a motorcraft one or is parts store Chineseium okay?

 

If I recall, the throttle pedal assembly comes as a unit with the sensor. There is a way to ohm-out the sensor and look for shorts. I don't know what readings you are looking for.

 

I am not familiar with Forscan, but if it allows you to data log the throttle sensor I/O you would be able to see it go to zero when the truck drops to idle.

 

This is along my line of thinking, I was going to set up forscan to watch throttle position and rpm tonight and have my wife drive me to Menards to pick up some desicrated tree carcasses, while I watch the laptop.

I looked at the throttle. It looks like it's an after market Chineseium piece. And it doesn't have the moving pedal assembly like the brake. Which explains why I've always been annoyed that even with the pedals ask the way towards the engine, the brake pedal is still a couple inches behind the throttle. (Have to lift foot up and back, then over to get on the brake). In two years I've never bothered to look under there.

So it looks like if that's my problem, to do the job right I'll either need to drop $500+ on the correct throttle pedal assembly. Or get the sightly cheaper non movable one and find a way to shim it out. Which still seems silly, and not quite kosher.

I'm going to have to check eBay I think.

Other thoughts?

 

Took the truck to Menards with the Mrs. tonight. Truck made it almost all the way there (24mi) without so much as a hiccup. Then she did it which was almost a sort of relief, if only because we had everything set up to record and caught it in the act.



The trottle drops out around 1233 for 0.4 seconds. I remember holding the throttle steady in the same position for as long as traffic would allow. Then letting off and pushing down again before the engine responded. We were on a hill and the truck downshifted. The RPM graph seems to reflect that, but I don't see the let off and reapply on the throttle graph.

Anyway, the truck lost power. The throttle position sensor acted in ways I didn't ask it to. I assume this is confirmation that I need a new throttle assembly?

I've been looking on line, and the best price I can find to bring my truck back to original is $530 at Tousley, and I could drive to get it tomorrow. Or if I decide I don't care about the accelerator pedal being 4" further away than the brake, I could replace the assembly with another non moving pedal assembly. I looked and the truck has the unit with the TPS and IVS integrated into a single unit. Does that mean that I am stuck buying a whole assembly instead of just the sensor?

I would appreciate all your thoughts on this.

Thanks,
Joe

Edit:The truck has now finally thrown a P0221 code. I think it's related. Clarification?

 

Don't quote me on this, but I think Ford sells the pedal assembly as one unit and in their service bays they do not just replace the sensor, they change the whole assembly. This does sound like a good opportunity to make your truck right and get the correct assembly in there.


P0221 is the throttle position sensor circuit fault. "An unexpected voltage from the Throttle Position Sensor (TPS) is sent to the Engine Control Module (ECM)."

 

It is an opportunity to make it right, but its a really expensive proposition. So far I haven't been able to find a 5 pin TPS sensor, that's just the sensor. So looks like I'm spending lots either way. I was almost hoping to rule this out, and find I have a dead cylinder or something equally ridiculous. I have a spare engine. This pedal is going to cost more than I payed for my running driving parts truck! Unfortunately the parts truck doesn't have the correct pedal either....

 

Try the local boneyards.

 

I've never heard of such a thing, non movable throttle. It doesn't move like the brake peddle, just pivots. Maybe I'm not visualizing your description correctly. Can you post a picture of the throttle assembly?

You are viewing APP in percent and RPM, all that looks correct since everything is in ms (milliseconds), not the TPS (throttle position sensor). Its purpose it to tell the PCM if the throttle is at idle, your foot off the peddle. Its a simple on-off switch on the peddle assembly and if the contacts fail, regardless of the peddle position the motor will go to idle, a fail safe device in case the APP fails and the engine starts to run away.

 

Sorry, I meant to say IVS (idle validation switch) instead of TPS. TPS and APP are the same thing depending on the tech terms one is referring to, brain fart on my end.

 

Auto zone carries it for $105 just bought one for one of the work trucks so far uts been working great.

 

I'll try to remember to snap a photo tomorrow. The stupid fancy truck has stupid fancy peddles that move in and out to accommodate people who's legs are poorly proportioned to their arms, I guess. So they pivot just like the normal ones, but the pedal itself rides on a linear rail, with a lead screw that pushes the pedal in and out several inches.

Also the problem it's solved, now. It was in fact the TPS, which is not replaceable on a 2002 with fancy pants pedals. Didn't have time to go scrap yarding. Had to pay $670 (after the people's republic of Commiesota got it's fair share). But the signal from the TPS is more stable than before, and the truck hasn't failed in 200 miles since.