Hey Guys,
just got a JET performance products Accu Speed sensor to readjust my speedometer after the addition of bigger wheels and tires and was reading through the install instruction and it says find the vss and yadi, yadi, yadi....where is it ? the book only gives locations for f-150's through 99' I am no mechanic the two choices sound like rear axle or on transmission up front or on the left? Anyone have any experience with this or installed one.
Trying not to break down and pay somebody to do this but don't want to f anything up....HELP!!


Thanks

 

According to the Haynes manual I am looking at the vehicle speed sensor is located on the top of the rear differential on Superdutys.

*Sorry* - I read "SuperCrew" and for some reason thought "Superduty"...

 

The 2001 EVTM does not have a direct ref to the VSS as a part.
It has the Output Shaft Speed Sensor, which is on the trans. The VSS ref is from page 31-2, but when I follow all the page refs, I don't see a VSS straight away. The pin on the Speed Control Servo takes input from the AirBag, Brake pedal position sensor ( and clutch if manual trans ) and the PCM, which is hooked to the transfer case sensor, and the output shaft speed snesor ( OSS ).

If it is now called a OSS rather then VSS ( Ford has changed names on stuff over the years with the same basic body style ) the OSS is on the trans at the rear on top for a 4R100 4x4, and on the driver's side for a 4R70 4x2 and a M5R2.
The OSS is a 2 pin connector C187, and has a Brown with light green stripe in it ( Signal Return ), and a Dark Brown with Yellow Stripe on it ( Output Shaft Speed Sensor signal to PCM ).

Don't know if this is what the JET device is looking for or not.

Sorry that is the best I can find right now, need to get back to work

Let us know.

 

Sscully,
I let you know how it turns out I will not have time to tear into it until Thursday or Friday but let me tell ya for a 4 wire simple installation their sure is a lot of work involved...this may be over my head but I will give it a shot.
Thanks for the info!

 

Don't know if the '02 is the same as my '01 was, but there was a second harness, in the back of the radio, that had a VSS signal line into it.

I think it was Pin # 9 on the smaller square connector. It was there to make the speed sensitive volume control work on the radio.

I used it to tie my electric fan cut-off to...

Might be worth a check before you go crawling under your truck.

Good luck and let us know how it works out.

 

B-Man,

Thanks, didn't think to look there ( JMC would have though ).

The VSS into the radio is Circuit 679, Gray with a black stripe in connector C224 ( mis marked in the connector pin out in section 130 of the EVTM ).

The VSS is connected to the PCM, on pin #68, in connector C174, and to the GEM on pin 21 in connector C243.

This circuit is also to the Speed Servo Control in connector C157, again it seems to start at the PCM on pin 68.

I missed it on page 31-2 when I found the OSS, as it was only called Vehicle Speed Input, this is the page that talked about the VSS, but it not call it out directly. ( didn't want to make the assumption that VSS and Vehicle Speed Input had the same function ).

So it seems that the PCM makes VSS from the inputs of the Transfer Case Speed Sensor and the Output Shaft Speed Sensor ( OSS ) The supply to the OSS is from pin 84, and after the OSS, it goes back to the PCM, and is spliced to the Tran Case Speed Sensor, which feeds back to the PCM on pin 7.

Strange the only place on page 31-2 that is it called VSS is in a balloon text box, next to the Speed Control Servo. It is not in the index under the same VSS directly.

B-Man, see I told you JMC was better at this then me

Thanks for the kick in the right direction.
BTW: I would be cautious of what this is doing, using VSS for Speed correction. Seems like that is the output of the actual, place it is taken before the PCM. I would have guessed that the correction would have needed to be prior to the PCM, or inside the PCM ( Chip / MicroTuner ).
Will be interesting to see how it works, and what it might to to the other items that rely on this ??

Good luck

 

Thanks for all the info, after all this I called ford they can recalibrate the vss for me, $77 and about 1 hour. Jet's getting their module back! It saves me a lot of hassle and about $75.
Thanks again!

 

CRAP,
Went down to ford they said they could do it and when I got down there they called to get the codes to change and at that point I was told no dice so back to installing the chip...I will let you guys know.

 

This is the last post I swear, went to 4 wheel parts even these guys were like uuhhh? where did you get this part? Could not get a hold of JET to get proper wiring instructions finnally just said forget it bit the bullet and bought the Hypertech Power Programmer $362 out the door but solved the shifting problems and the speedo errors, this model also has the dual gas option which allows you to run 87 or 91 octane gas.

JET AccuSpeed Sucks!!
Thanks!

 

JET is right up the street from me ( well actually up the street a couple of blocks and over a couple more. They have been the chip business since the early 80's. Sorry to hear that there parts were so hard to install. They used to be a Carb. shop ( did great rebuilds.) then when computer controlled engines came out they started dabbling in burning PROMS for chevys. The rest is history. They used to be pretty easy to get along with, see if they will let you return your unused part. Don't forget to tell them that you are on the boards alot and that you would like to mention how well they treated you. Good luck!!!!

 

Fair enough, I will say their is probably nothing wrong with the product as far as quality and craftsmanship but unfortunately four guys not being able to figure out how to install it for what was advertised as "plug and play"...not so sure about that. I bought the part from Truckperformance.com and they were definately pretty cool about returning it only charged me a 10% restocking fee and seemed very understanding of my situation. As this has been my only experience with JET I may give them another chance but was most dissapointed in the fact that is was advertised as plug and play and in the end it would have cost me about $140 to have installed and take upwards of 2 hours.