NOS Dealer Installed CC FORD F2TZ-9A818-A

[Rembrant]

The '87-04 8.8" ABS sensor put out 108 pulses per rev, which is what the '92-97 PSOM used to generate a standard 8,000 pulses-per-mile VSS (Vehicle Speed Signal) for other modules to use (including both the pre-'93 cruise module, & the '93-04 cruise servo). Older factory vacuum cruise systems used a 6 pulse-per-rev sensor on the speedo cable (except '92), which if you do the math, is very close to 108 pulses on the rear axle. So the systems will work with each other's sensors.

Steve,

Couple questions:

1. I thought the pulses per rev of the later (transmission mounted) VSS was 8 instead of 6, no? I'm referring to the one used in the 1987-1991 era, that the cable plugged into like pictured above. I thought that speedo cables were meant to be spinning approx 1000 revs per mile, and thus with a sensor output of 8 pulses per rev, you'd get the 8000 pulses per mile required? Or am I remembering this incorrectly?

I spoke to Rostra a while back (months ago) about using their system with the trans mounted VSS I have, and I thought they said it put out 8000 pulses per mile, although I could be remembering that wrong.

2. What calculations did you use to come up with the trans mounted VSS pulses and the diff mounted ABS pulses being very close to the same per mile? I've been trying some math with these numbers and they don't come out anywhere even close to the same, so I'm clearly missing something...

 

[Rembrant]

The '87-04 8.8" ABS sensor put out 108 pulses per rev, which is what the '92-97 PSOM used to generate a standard 8,000 pulses-per-mile VSS (Vehicle Speed Signal) for other modules to use (including both the pre-'93 cruise module, & the '93-04 cruise servo). Older factory vacuum cruise systems used a 6 pulse-per-rev sensor on the speedo cable (except '92), which if you do the math, is very close to 108 pulses on the rear axle. So the systems will work with each other's sensors.

Steve,

Couple questions:

1. I thought the pulses per rev of the later (transmission mounted) VSS was 8 instead of 6, no? I'm referring to the one used in the 1987-1991 era, that the cable plugged into like pictured above. I thought that speedo cables were meant to be spinning approx 1000 revs per mile, and thus with a sensor output of 8 pulses per rev, you'd get the 8000 pulses per mile required? Or am I remembering this incorrectly?

I spoke to Rostra a while back (months ago) about using their system with the trans mounted VSS I have, and I thought they said it put out 8000 pulses per mile, although I could be remembering that wrong.

2. What calculations did you use to come up with the trans mounted VSS pulses and the diff mounted ABS pulses being very close to the same per mile? I've been trying some math with these numbers and they don't come out anywhere even close to the same, so I'm clearly missing something...

By the way, here is a picture from the back of the module (Clipped from the Ebay ad).

So, only a single wire input for speed signal, which is fine. I just need to know if the signal from my VSS (8000 pulses per mile?) would work...

Also...if you look in the pictures of the kits, you'll see what looks like an SAE plug pigtail with two green wires....

Meant to fit one of these sensors? I happened to see this one the other day on a Rockauto closeouts deal email...but I have no idea where it mounts on an F150. I don't recognize this sensor at all. It is listed as a cruise control sensor.

[Steve83]

1. I thought the pulses per rev of the later (transmission mounted) VSS was 8 instead of 6, no?

I specifically remember breaking open a jammed inline sensor & seeing 6 magnets. I thought I had seen the same in the bottom-end sensor, but now that you bring it up, I don't specifically remember tearing one open.

2. What calculations did you use...?

It's been decades, so I don't remember that, either. But you have to find the ratio of the worm-drive for the bottom end of the speedo cable, which is NOT simply the tooth-count ratio, like it is for other gear drives. And it's not the same, but it's close enough to work. Another reason I think it will work is that I think the cruise module is the same for '91 trucks (worm drive) and '92 trucks (ABS).

I don't recognize this sensor at all.

It just looks like another version of the sensor in my pic. Different connections, but the same guts.

BTW

I still think the '92-04 servo is a better system. And it uses the same control buttons as any other Ford cruise.

[Gary Lewis]

1. I thought the pulses per rev of the later (transmission mounted) VSS was 8 instead of 6, no?

I specifically remember breaking open a jammed inline sensor & seeing 6 magnets. I thought I had seen the same in the bottom-end sensor, but now that you bring it up, I don't specifically remember tearing one open.

2. What calculations did you use...?

It's been decades, so I don't remember that, either. But you have to find the ratio of the worm-drive for the bottom end of the speedo cable, which is NOT simply the tooth-count ratio, like it is for other gear drives. And it's not the same, but it's close enough to work. Another reason I think it will work is that I think the cruise module is the same for '91 trucks (worm drive) and '92 trucks (ABS).

I don't recognize this sensor at all.

It just looks like another version of the sensor in my pic. Different connections, but the same guts.

BTW

I still think the '92-04 servo is a better system. And it uses the same control buttons as any other Ford cruise.

I'm not all that knowledgeable on the speed controls, but I'm not sure the pulse/mile count is a big issue. Don't the controls just keep the pulses at whatever the rate was when you hit the button? It might change the low speed where it will start working, but ....

[Rembrant]

I thought I had seen the same in the bottom-end sensor, but now that you bring it up, I don't specifically remember tearing one open.

I hadn't thought of breaking one open. I do have a brand new one, but the spare M5OD trans I have actually has a damaged VSS in it, so maybe I'll check it. I forgot I even had it until you mentioned that.

I didn't realize that the speedo drive was not a normal ratio, but using the 8/18 teeth (2.25:1 ratio), the math works out that my speedo cable is spinning 953 revolutions per mile, which is pretty close to 1000/mile, which I thought was what cable driven speedos were set-up for (not just Ford, all of them).

I too prefer a servo operated cruise. I've used the Rostra car kits on motorcycles for years, and they work very well. However, for the cheap price of this kit, I might give it a whirl.

Thanks for the replies gentlemen! Much appreciated.

 

[Gary Lewis]

I thought I had seen the same in the bottom-end sensor, but now that you bring it up, I don't specifically remember tearing one open.

I hadn't thought of breaking one open. I do have a brand new one, but the spare M5OD trans I have actually has a damaged VSS in it, so maybe I'll check it. I forgot I even had it until you mentioned that.

I didn't realize that the speedo drive was not a normal ratio, but using the 8/18 teeth (2.25:1 ratio), the math works out that my speedo cable is spinning 953 revolutions per mile, which is pretty close to 1000/mile, which I thought was what cable driven speedos were set-up for (not just Ford, all of them).

I too prefer a servo operated cruise. I've used the Rostra car kits on motorcycles for years, and they work very well. However, for the cheap price of this kit, I might give it a whirl.

Thanks for the replies gentlemen! Much appreciated.

Yes, I once found that the target speed for the speedo cable is 1000 revs/mile, which at 60 MPH is 1000 RPM. Don't remember exactly where I found it, but it was pretty authoritative. And, I've documented it on the Calculator tab here: Driveline/Speedometer Gears.

[Steve83]

It might change the low speed where it will start working, but ...

Yes, that can be a problem if the pulses are way off; the cruise may not engage at normal driving speeds, or it may keep working at low speeds when it should cut off. It's a bigger problem with the '93-04 system, which actually responds in MPH (which is why I like it so much more).

...I thought was what cable driven speedos were set-up for (not just Ford, all of them).

Did you read the TSB in this caption?

https://supermotors.net/getfile/185339/thumbnail/vss.jpg

This one is also worth reading before you commit to that system:

https://supermotors.net/getfile/491917/thumbnail/cruisetroubleshooting.jpg

I too prefer a servo operated cruise. I've used the Rostra car kits on motorcycles for years, and they work very well.

The pre-'93 servo is vacuum-operated. The '92-04 servo is electronic, which is a vast improvement. I've repaired a Rostra, and I'm not a fan.

[Gary Lewis]

It might change the low speed where it will start working, but ...

Yes, that can be a problem if the pulses are way off; the cruise may not engage at normal driving speeds, or it may keep working at low speeds when it should cut off. It's a bigger problem with the '93-04 system, which actually responds in MPH (which is why I like it so much more).

...I thought was what cable driven speedos were set-up for (not just Ford, all of them).

Did you read the TSB in this caption?

https://supermotors.net/getfile/185339/thumbnail/vss.jpg

This one is also worth reading before you commit to that system:

https://supermotors.net/getfile/491917/thumbnail/cruisetroubleshooting.jpg

I too prefer a servo operated cruise. I've used the Rostra car kits on motorcycles for years, and they work very well.

The pre-'93 servo is vacuum-operated. The '92-04 servo is electronic, which is a vast improvement. I've repaired a Rostra, and I'm not a fan.

Why is the electronic servo "a vast improvement"? I've gotten along well with the vacuum-powered ones, but what am I missing?

[Steve83]

Why is the electronic servo "a vast improvement"?

My I6 spends most of its life at WOT, which means no vacuum to operate the servo. I've had it drop out on hills & when towing, back when I used the vacuum system. V8s don't struggle as badly, but I still consider it a big weakness. But the thing I like most about the '93-04 servo (and '04-up software) is that each press of the buttons is exactly 1 MPH. So if you're in a 55 zone holding that speed, and it changes to 65, you can rattle off 10 presses of the ACCEL button, and it'll ease up to exactly 65 (it doesn't go to WOT like most other systems). Same for the COAST(decel) button. I haven't found any other cruise with that functionality except the very newest high-trim Maxima. My father thought his '10 Dodge dually had it, but it doesn't. Ford had it in the early 90s, and that system can be added to almost anything - including bullnoses (though it's much easier with an '87-up rear axle with the ABS sensor). I actually drive on cruise whenever I can - even in traffic.

[Gary Lewis]

Why is the electronic servo "a vast improvement"?

My I6 spends most of its life at WOT, which means no vacuum to operate the servo. I've had it drop out on hills & when towing, back when I used the vacuum system. V8s don't struggle as badly, but I still consider it a big weakness. But the thing I like most about the '93-04 servo (and '04-up software) is that each press of the buttons is exactly 1 MPH. So if you're in a 55 zone holding that speed, and it changes to 65, you can rattle off 10 presses of the ACCEL button, and it'll ease up to exactly 65 (it doesn't go to WOT like most other systems). Same for the COAST(decel) button. I haven't found any other cruise with that functionality except the very newest high-trim Maxima. My father thought his '10 Dodge dually had it, but it doesn't. Ford had it in the early 90s, and that system can be added to almost anything - including bullnoses (though it's much easier with an '87-up rear axle with the ABS sensor). I actually drive on cruise whenever I can - even in traffic.

Interesting. I've not had the lack-of-vacuum problem. Dad's truck, when it had Rusty's warmed-up 351M and the ZF5, pulled the steep hill in eastern TN on I40 on cruise at 65 MPH. And the bed was loaded to the top of the cab's roof with furniture we took from OK to DE. R's were probably 1800, and it just motored right on up. But, I didn't tow with it so maybe the vacuum would have been low enough then not to handle the cruise.

As for getting 1 MPH per button push, my 2015 F150 does that. And, it really is nice. However, the cruise on that thing is so aggressive that it really kills the MPG by constantly bringing in the turbos.

Anyway, I was just curious why, and you've answered the question. Thanks.