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Old 05-31-2018, 10:30 PM   #1
Texas240
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Default volvo 240 electronic speedo PPM signal?

Anybody know what the pulses per minute on the 240 electronic speedo is coming from the rear end? Swapping rear ends that does not have a sensor in the rear end and I'll be going off of the VSS sensor in my 4L60e.
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Old 06-01-2018, 12:03 PM   #2
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93 has 48 tooth tone ring in rear end. Don't you have ABS brakes?
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Old 06-01-2018, 10:05 PM   #3
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93 has 48 tooth tone ring in rear end. Don't you have ABS brakes?
I need the pulses per minute. I have v70r brakes and abs delete.
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Old 06-01-2018, 11:33 PM   #4
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Lookup your tire size and find the revs/mile. For instance, 195-60R15's are 833 revs/mile.

https://tiresize.com/tiresizes/195-60R15.htm

Then multiply by the number of tone ring teeth (48 for a '93) to get pulses per mile coming from a stock 240 rear end.

[Note: the Vss signal from the speedo to the LH2.4 box is setup for 12 teeth per differential rev. For a '93, the speedo divides the 48 teeth/rev signal by 4 to get the 12 teeth/rev Vss signal to LH2.4 ECU.]
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Old 06-01-2018, 11:53 PM   #5
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Lookup your tire size and find the revs/mile. For instance, 195-60R15's are 833 revs/mile.

https://tiresize.com/tiresizes/195-60R15.htm

Then multiply by the number of tone ring teeth (48 for a '93) to get pulses per mile coming from a stock 240 rear end.

[Note: the Vss signal from the speedo to the LH2.4 box is setup for 12 teeth per differential rev. For a '93, the speedo divides the 48 teeth/rev signal by 4 to get the 12 teeth/rev Vss signal to LH2.4 ECU.]
That makes for an odd number for a PPM
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Old 06-02-2018, 04:36 AM   #6
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Did you mean pulses per mile?

But, if you car had ABS, just take signal from front wheel abs sensor. Speedo will take that signal straight in.
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Old 06-02-2018, 02:26 PM   #7
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You can get a Dakota digital box and adjust it till it matches off the rear end you swap in. Are you worried about speedometer function?
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Old 06-02-2018, 08:57 PM   #8
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Quote:
Originally Posted by OttoB View Post
Did you mean pulses per mile?

But, if you car had ABS, just take signal from front wheel abs sensor. Speedo will take that signal straight in.
No longer have the sensors.

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Originally Posted by cosbySweater View Post
You can get a Dakota digital box and adjust it till it matches off the rear end you swap in. Are you worried about speedometer function?
My rear end Iím swapping in doesnít have a sensor and Iíve been looking at the Dakota box. Just nice to know what our stock speedo intakes for ppm.
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Old 06-04-2018, 12:31 PM   #9
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VSS on the 4L60E puts out a 40 PPR (pulse per revolution) vr signal. This gets conditioned by the GM pcm to a 4000 PPM (pulse per mile) digital signal for the speedo,cruise,etc. The volvo speedo takes a 12 or 48 pulse per revolution VR signal directly from the rear axle. I would say if you can adapt the volvo vss to the new rear or run off a front ABS sensor that would be the easiest solution.
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Old 06-04-2018, 02:37 PM   #10
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The pulses per mile is marked on the later electronic speedometer faces. For non ABS cars this is wheel revolutions per mile, x 12 teeth on the tone ring. For ABS cars it is x48 since they use a finer tooth tone ring.

Sedans used K10042 speedometer. Wagons had slightly larger tires and used the K9800 speedometer. Not sure of the ABS numbers but it should be approximately 4x. (Edit: Looked them up, it's K39200 and K40168)

So, for your speedometer to be accurate, you will need to do the math so the 4L60E output gets converted to the same pulses/mile as marked on the speedometer. I don't know much about this transmission but I presume you'll have to take the diff reduction into account as well.
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Old 06-04-2018, 04:05 PM   #11
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Quote:
Originally Posted by Khrrck View Post
The pulses per mile is marked on the later electronic speedometer faces. For non ABS cars this is wheel revolutions per mile, x 12 teeth on the tone ring. For ABS cars it is x48 since they use a finer tooth tone ring.

Sedans used K10042 speedometer. Wagons had slightly larger tires and used the K9800 speedometer. Not sure of the ABS numbers but it should be approximately 4x. (Edit: Looked them up, it's K39200 and K40168)

So, for your speedometer to be accurate, you will need to do the math so the 4L60E output gets converted to the same pulses/mile as marked on the speedometer. I don't know much about this transmission but I presume you'll have to take the diff reduction into account as well.
Iíll probably use the Dakota digital speedo box but knowing where each one is close
To means I can dial in the speedo when I swap in the c4 rear end.
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Old 06-05-2018, 06:18 PM   #12
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The SGI-5 or equivalent, right? Should work... Are you tapping the signal from the sensor or the PCM? What tire size and diff ratio?
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Old 06-05-2018, 08:39 PM   #13
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Originally Posted by Khrrck View Post
The SGI-5 or equivalent, right? Should work... Are you tapping the signal from the sensor or the PCM? What tire size and diff ratio?
Thats the one. I'll probably tap into from the pcm since I have a VSS wire right there not being used. Right now I'm 225/45/17 with a 3.73
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Old 06-06-2018, 03:06 PM   #14
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~808 revolutions per mile at that tire size * 3.73 driveshaft revolutions per tire revolution * 40 pulses per revolution (I'm assuming that's correct...) = 120,554 pulses per mile from the sensor on the transmission. So in the ballpark of 3x what the speedometer expects, not too difficult to convert if the box will do fine adjustments.

I'm not sure what the PCM does to that signal though. My Googling says the output on the other side of the PCM is programmable in some way.
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Old 06-06-2018, 08:45 PM   #15
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Quote:
Originally Posted by Khrrck View Post
~808 revolutions per mile at that tire size * 3.73 driveshaft revolutions per tire revolution * 40 pulses per revolution (I'm assuming that's correct...) = 120,554 pulses per mile from the sensor on the transmission. So in the ballpark of 3x what the speedometer expects, not too difficult to convert if the box will do fine adjustments.

I'm not sure what the PCM does to that signal though. My Googling says the output on the other side of the PCM is programmable in some way.
I'd hope. Thanks for the help.
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