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LH 2.4 Speed Sensor w. T-5 Transmission

TR Conn

Member
Joined
Dec 13, 2006
Location
Long Beach, Ca
Rather than dredge up several old threads on the subject Ill just link to them.

I have a B230F LH 2.4 in a 122S. I'm running a T-5 transmission and I've tried several things to get the Volvo speed sensor to work.
As an experiment I wired up the Ford speed sensor..
It works great!!!:-D
This is hooked up to a non ABS speedometer. (12 pulses/tire revolution).
I got lucky with the first driven gear and it is accurate within 1 MPH.
By changing the drive gear and the driven gear you can compensate for different gear ratios and tire sizes.
There probably isn't a combination that will work with the ABS speedometer (48 pulses/tire revolution). But if you are not using ABS this may work for you.
As a bonus, the Volvo Speedometer cable can be modified to work with the Ford speed sensor if you are using a cable driven speedometer and just the electronics from the newer speedometer to satisfy the ECU.

There are lots of threads on this subject, heres just 3.

http://forums.turbobricks.com/showthread.php?t=221167
http://forums.turbobricks.com/showthread.php?t=213193
http://forums.turbobricks.com/showthread.php?t=204656
 
Nice fine. Is the Ford sensor the one that comes with the T5 or did you have to get a specific one?
 
In your testing, have you found out if there's a difference in the pulse to the speedo and from the speedo?

Meaning, if you wired your, now proven, Ford T5 electric speed gear, directly to your LH 2.4, will it work the same?
 
In your testing, have you found out if there's a difference in the pulse to the speedo and from the speedo?

Meaning, if you wired your, now proven, Ford T5 electric speed gear, directly to your LH 2.4, will it work the same?

The speedo is accurate and the feed to the computer seems to be just what it wants.
I can feel the fuel cut-off on deceleration, the CEL hasn't lit up nor have I retreived any fault codes.
It is not wired directly to the ECU, it is wired to the speedometer, which gives the ECU the pulses it needs.

The VSS is the stock Ford one. Fords look for 8000 pulses per mile, Volvos look for about 7800 IIRC
 
The speedo is accurate and the feed to the computer seems to be just what it wants.
I can feel the fuel cut-off on deceleration, the CEL hasn't lit up nor have I retreived any fault codes.
It is not wired directly to the ECU, it is wired to the speedometer, which gives the ECU the pulses it needs.



Right right, just wondering if you tested to see if the pulse to the ECU is any different...at any different rate.

I'm asking because I'd like to wire up LH 2.4 in my early 242 without swapping in a modern cluster...If I could get away with swapping the diff to a tone ring model and run the leads direct to the ecu and replace the speedo, that'd be tight!
 
Good, this answers that question without my testing. I was going to try the sensor hooked to a later model speedo in my 244 when I install the trans, guess I know it works now.

VERY good info, thanks for sharing.
 
You could also run a dakota digital vss on the tranny thats programmable, if you dont feel like takeing the tail shaft off and regearing. As far as I know, the ecu dont care, just wants to know if your moving or not. Now if it had a speedlimiter, that could suck, as the volvo sensor fed my dsm ecu with a signal that was 2.5 times.....so most of my dyno runs were 200mph+!
 
Right right, just wondering if you tested to see if the pulse to the ECU is any different...at any different rate.

I'm asking because I'd like to wire up LH 2.4 in my early 242 without swapping in a modern cluster...If I could get away with swapping the diff to a tone ring model and run the leads direct to the ecu and replace the speedo, that'd be tight!

You could get a later model speedometer, strip off the unnecessary parts and hide it behind the dash.
You can't wire directly to the ECU, there is something in the speedometer curcuit that needs to be there as an intermediary.
 
What rear end ratio do you have?

My set up is in a 122S which has a 4.10:1 rear.
I'm running 205-70-14 tires
Using a 19 tooth driven gear and a 6 tooth drive gear

The Ford VSS has several gears available, about $10, or poke through the JY. The VSS for most any Ford vehicle from about '78 to '93 and maybe later, are the same. Automatics use a slightly different gear, but can be used if you snip about 1/4 inch off the tip.

This is a link to a calculator for the VSS:

http://accutach.com/FordMustangVSSCalculator.aspx

Note: the 21 tooth gears wear out in about 2500 miles, the teeth are so thin if there is any resistance they will just break off.
 
You could get a later model speedometer, strip off the unnecessary parts and hide it behind the dash.
You can't wire directly to the ECU, there is something in the speedometer curcuit that needs to be there as an intermediary.

I'm thinking this'll have to be the answer!

strip her down, make a nice little case and sneak it in there...Then just run a cable to my r-sport cluster as usual.
 
Another option would be the converter from an GM vehicle. They dont fail like the Volvo speedo stuff does with broken solder joints and the problematic capicters over a few years. They convert to a 4k and 2k pulse per mile. Most companies drop the signal count to the ecu and cruise, not sure why, but they do.

If I remember correctly too, the Autometer unit actually outputs PPM, something like 16 pulses per rev of the sensor.
 
Another option would be the converter from an GM vehicle. They dont fail like the Volvo speedo stuff does with broken solder joints and the problematic capicters over a few years. They convert to a 4k and 2k pulse per mile. Most companies drop the signal count to the ecu and cruise, not sure why, but they do.

If I remember correctly too, the Autometer unit actually outputs PPM, something like 16 pulses per rev of the sensor.

So the ECU just needs a signal, any signal, to gauge whether accelerating or decelerating?
 
Yep, it dont care how fast your going......thats if there is no speedlimiter internally. It needs a square wave ppm tho, just not the sign wave off the diff as far as I know.
 
Yep, it dont care how fast your going......thats if there is no speedlimiter internally. It needs a square wave ppm tho, just not the sign wave off the diff as far as I know.

square wave vs. sign wave? what's the difference.

if it just needs to know faster or slower, than why can't the tone ring just be wired directly?
 
You know...Im really not sure? Maybe it needs the rising and falling edges? Either way, the gm units are plentiful and are generally tucked on the passenger kickpanel.
 
Nope, the gm converter take in the wave from the diff....coverts it, and send the signal to the ecu.

Found this on google. http://www.tbichips.com/drac/

come to find out its an AC sine wave, not a dc square wave that I beleive the ecu is looking for.

My new autometer electro speedo acutally has an output. I feed it the sin wave from the diff, it coverts it just like the stock one, and outputs to the ecu/cruise.
 
Excellent reference, that makes total sense.

So instead of reinventing the wheel, I can recycle!

Sounds like this GM piece converts the signal to 2,000 pulses per mile for the ECU; do we know that's the same for the Volvo system.

I'm intrigued by this. Again, if its not the same ppm, one might get lucky with the GM unit's cruse control setting and abs sensor setting, at 4k & 128k ppm
 
Yep......I was going to use it till I found my dsm ecu read the vovlo signal. One more thing here......a company called jaycar.com makes a pulse box that's adjuatable. Its like 55.00 tho.
 
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