AP50 Cruise Control and Speedo Sensor

Submitted: Sunday, Mar 21, 2004 at 14:36
ThreadID: 11429 Views:11308 Replies:5 FollowUps:4
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Replying to a post in January (postID:9702) "joc45" and "chrisfrd" had some very helpful info on using the existing speedo sensor to drive the cruise control instead of having to hook up magnets to the tailshaft. As a retired clerk I now have time to fiddle and am enjoying it immensely but don’t have much experience. I am fitting the AP50 to a 100 series Standard wagon and the speedo sensor in the rear of the transfer case has three wires: one grounded, one to the ignition and one to the speedo. From a remark by chrisfrd I take it that the two ungrounded wires are the ones to connect to the AP50. I don’t know how the sensor works but my query arises from the fact that the schematic circuit diagram in the Toyota manual shows a connection inside the sensor of the +12v via a resistance to the wire to the speedo. I know the diagram is only a schematic but how does this sensor provide a voltage in the order of 0.8v which is what the AP50 manual suggests would be present from the magnets on the tailshaft at a speed of 50kph?
On a different issue, the current AP50 unit gives an option of cutting an external black wire loop in order to change the range of the unit from 2000 ppm (pulses per mile) to 5000 ppm. Choosing the latter means 1 pulse each 0.32 metre or 43 pulses/sec at 50 kph. The Toyota has 30.7inch tyre diameter and 4.3:1 diff so 2 magnets on the tailshaft would result in 49 pulses per sec at 50kph. Is this right and therefore do I cut the loop?
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Reply By: V8troopie - Monday, Mar 22, 2004 at 01:20

Monday, Mar 22, 2004 at 01:20
I just fitted the AP 50 to my aging troopie. its really no big deal to fit the magnets if one araldites them on carefully.
I used 2 magnets ( for balance - just one magnet is a silly idea, IMO)
The troopie runs Cooper AT tires on the standard split rims.
I did have to cut the black loop to get it to work.
It works very well in my troopie.

Remember, the sensor from the magnets puts out pulses, not a steady voltage. The 0.8v woul be the average from the pulses as measured on a meter. If you were to look at it on an oscilloscope you would see that the peak voltage of the pulses is considerably higher.

AnswerID: 51341

Follow Up By: Adrian Walker - Tuesday, Mar 23, 2004 at 23:17

Tuesday, Mar 23, 2004 at 23:17
Thanks for confirmation of the 2 magnets and cutting the loop. I have since spoken to Tech Help at Command Products who distribute AP50 and he suggested one magnet but agreed two would probably work with the loop cut. He also strongly advised against using the sensor on the Toyota as it could damage the Toyota computer.
FollowupID: 313435

Reply By: Michael Ralston - Monday, Mar 22, 2004 at 21:54

Monday, Mar 22, 2004 at 21:54
I was in at Autobarn the other day talking about fitting the AP50 to my 80 series standard (1HZ). He informed me, probably incorrectly, that there was not enough vaccuum to run the thing. Could you let me know the truth? Thanks
AnswerID: 51489

Follow Up By: Adrian Walker - Tuesday, Mar 23, 2004 at 23:23

Tuesday, Mar 23, 2004 at 23:23
Command Products said nothing about lack of vacuum. The AP50 manual deals with engines which have separate vacuum pumps (like the 100 series, and I presume the 80 series also). It simply mentions fitting the connection between the pump and the non-return valve (on the 100 series the non-return valve is on the reservoir, not on the booster). Will let you know if it works in a day or so!
FollowupID: 313436

Reply By: joc45 - Monday, Mar 22, 2004 at 22:06

Monday, Mar 22, 2004 at 22:06
Hi Adrian,
My guess is that Toyota use a "Hall-Effect Device" to generate the pulses, rather than an electromagnetic sender as in the Nissan. This is a solid-state magnetic sensor, and needs volts to run it. The lead to the speedo should still put out pulses, but I'd be uncertain of the voltage. With the tailshaft running, you should be able to measure a voltage with an AC multimeter. A CRO would be best.
My AP50 used the black loop wire, but I've since worked on one which was completely programmable; ie no loop. Had more control over the division, but on a HiLux, I still had to go down to one magnet to get it to work properly. I made up a piece of steel the same weight as the magnet and fixed that on the other side to balance the thing.
I can be emailed on gerron at bigpond dot net dot au
AnswerID: 51492

Follow Up By: Adrian Walker - Tuesday, Mar 23, 2004 at 23:32

Tuesday, Mar 23, 2004 at 23:32
Thanks for the info. I like the idea of balancing the magnet if I have to use only one magnet, which is what the guy at Command suggested also. He also answered my query about the clutch switch as I could not see how the original circuit worked with the reed switch in series with the brake switch. He suggested I use the short purple wire on the module - extend it to a switch on the clutch (reed switch or micro-switch which is what I'm using) and wire it so that 12v appears on the purple wire when the clutch is depressed. That way the brake switch is wired separately using the 2 brown wires (one brown and one brown with white trace.)
FollowupID: 313439

Reply By: Michael Ralston - Monday, Apr 05, 2004 at 21:50

Monday, Apr 05, 2004 at 21:50
I was interested to know how you went with the installation of the cruise control and any feedback you might have about how it performs. How does it handle hills-up and down? I have a 1991 80 series Std with the 1HZ motor. Think it has a different speedo to the later (>1996) models. I was interested in any tips you might have regarding the wiring and weights.
Thanks in anticipation.
AnswerID: 53314

Follow Up By: Adrian Walker - Wednesday, Apr 07, 2004 at 23:43

Wednesday, Apr 07, 2004 at 23:43
The cruise control is connected and working well. The two magnets are OK as I have cut the black loop on the module. I have also set the sensitivity to high as it was a bit sluggish when on medium.
The microswitch on the clutch sits on the crossbar above the pedal assist mechanism - held on with a bracket made of Colorbond downpipe folded double and clamped with two short bolts. The switch uses the NC contact and the common contact - one side to the purple wire on the module and the other side to 12v. The switch is held open by the pedal assist mechanism and springs closed when the clutch pedal is depressed and the mechanism swings away form the switch.
I took the advice of the others who used Araldite and wire to fix the magnets on the transmission shaft. The bracket for the pickup fitted neatly on the fuel tank cover shield (I ground the points off the self tappers before inserting them and made sure they were well clear of the tank itself!)
"joc45" has sent me a circuit that enables the use of the Toyota speed sensor but at present the magnets are working well.
Have fun - I did - a whole week of it! These blokes who fit it in a day must work long hours.
FollowupID: 315313

Reply By: Michael Ralston - Thursday, Apr 08, 2004 at 21:34

Thursday, Apr 08, 2004 at 21:34
Thanks for the reply. The info you have passed on will be very helpful. I was interested that you used 2 magnets. Some threads seem to suggest that this results in limited ability to cruise at higher speeds. Has this not been a problem for you? Hopefully the installation on my car will take a little less than a week, thanks to your help
AnswerID: 53739

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