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Guest Message by DevFuse
 

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how do i mimic a VSS?


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49 replies to this topic

#26 julianco

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Posted 10 December 2013 - 06:10 PM

That's what I wanted to hear.  Thank you Gloyale.

I was just wondering if there was anything in the circuit that helped shape/clean the wave form.  But since it's just getting 5v power from the ECU and grounding when the magnet comes by..

I'll be testing in the next few days and will update.



#27 ivans imports

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Posted 11 December 2013 - 11:18 AM

perty nice reed switch for  a old car



#28 julianco

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Posted 11 December 2013 - 06:23 PM

Call me struggles.  This is what I've been trying, but I can't get the switch close. I've bought a few different reed switches new and still no dice.  Giving up and turning back other, more expensive ideas.  Toying with the idea of getting a full custom dash as there is no tach in the '78 dash, the temp gauge is not compatible with the new ECU and would need the '78 temp sensor wired in with either a custom bung or some other way... And then I could just buy a speedo with a built in VSS. Though it's probably the most expensive of routes, something I would probably have to pay someone to do for me, it would clear up a few problems all at once.

This is the '78 speedo with the new reed switched placed in the same place as the GL speedo's. Doesn't work and not sure why.



#29 Gloyale

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Posted 11 December 2013 - 06:45 PM

temp gauge can be corrected to match EA/EJ stuff by adding a 270 ohm resitor parallel to the sender to ground at the engine.  This corrects the gauge very closely.  It's a whole seperate signal  from ECU temp sender.

 

 

For the reed switch I was more suggesting utilizing the whole speedo unit from the EA81.  There is probably a magnet on the shaft of that one that triggers the reed switch.  At very least will need that shaft.



#30 julianco

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Posted 11 December 2013 - 08:21 PM

Yeah, that is what I was hoping to do for the speedo, but the guts don't match up to well...

 

Thanks for the tips on the temp gauge, I'll check into that... 

So there is a straight from temp sender to gauge wire?


Edited by julianco, 11 December 2013 - 08:27 PM.


#31 ivans imports

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Posted 12 December 2013 - 09:05 AM

3 way speedo cable tee



#32 julianco

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Posted 12 December 2013 - 10:37 AM

You have a line on those?



#33 robm

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Posted 12 December 2013 - 11:58 AM

Is there a way to glue a small magnet to something that rotates inside that housing?



#34 julianco

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Posted 12 December 2013 - 12:42 PM

robm - I thought about adding a magnet to the internals of the speedo, but was afraid that it would throw off the function of the speedo itself.

 

I'm about to order a hall effect sensor from smallcar - this one http://www.smallcar....roduct_id=29880

They will sell the sensor without the kit for $16 (since it's made to match a vanagon hub).  Plan is to set that up with magnets probably on the drive shaft since it's more out of the way than an axle.  Now i need to figure out how many magnets.  Signal is supposed to be 4000 pulses per mile.  I think that's 5 pulses per wheel rotation... so how many pulses per drive shaft rotation?



#35 Gloyale

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Posted 12 December 2013 - 01:03 PM

Supposed to be 4 pulses per revolution of the cable. 

 

Not sure how many cable turns are in a axle turn.



#36 julianco

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Posted 12 December 2013 - 01:08 PM

Well it needs to be 1/16" away from the passing magnets, so drive shaft probably won't work unless I can mount it really close to one of the ends.  Otherwise it will have to be on the axle right next to the tranny and I'll fabricate some kind of bracket to attach to the tranny and position the sensor.



#37 julianco

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Posted 12 December 2013 - 01:10 PM

Yeah, I was wondering the same.  The small car kit uses 5 pulses per rotation of the wheel (of course that's a vanagon size wheel).  I've been told both that it is very important and not important at all to get that exactly right...

The guy who just sold me the sensor says that it will work even with only 1 pulse per revolution - the ECU just needs to know whether or not the car is moving - he says.



#38 julianco

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Posted 12 December 2013 - 01:12 PM

Wow, I've really jacked this thread... OP never posted after the first.



#39 Gloyale

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Posted 12 December 2013 - 01:36 PM

You didn't jack it just revived it.  Which is good, it means you where searching for your answer before just repeating the same question over and over like sometimes happens.

 

I think he probably solved it back in 2009 when it was posted.  His swap was easy Loyales have VSS built in/wired up already just gotta splice in the EJ wire.



#40 julianco

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Posted 12 December 2013 - 01:46 PM

True. Well I'm going the easier route, but will update when the parts arrive.



#41 julianco

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Posted 23 January 2014 - 09:49 PM

So I've been too busy for a while but had some time yesterday to mount the improvised VSS.  Since the axles move too much for a regular gap between the magnets and the sensor, I decided to mount on the drive shaft where it enters the transmission (sensor on the tranny and magnets on the driveshaft).

The magnets that came with the small car auto kit were long thin cylinders and they have to be sensed at the end so they wouldn't work to attach to the driveshaft. So I ordered some of these little guys http://www.kjmagneti...il.asp?prod=D21

I cut up an old plastic cutting board for a mounting bracket for the hall effect sensor.

 

jb welded the magnets to the driveshaft

 

And put them together.



#42 julianco

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Posted 23 January 2014 - 09:58 PM

This fixed the problem I had with the car wanting to die at stops - coming down from RPM.  And it seems to run better overall, BUT, now when I hit about 33 mph, it starts to die.  

I've only driven it once, but it seems like I can drive right at the 33ish mark, and the car will run great below and as soon as I go over, start  -I think- cutting spark.  And if I stay over the mark, the engine will die.

 

I put 5 magnets evenly spaced (probably not exactly) on the drive shaft.  I'm thinking it's the wrong number.  

Anybody know how to figure the right number?  

 

For the Vanagon, the axle mounting bracket has 5 readings per rotation.

 

The subie speedo VSS's have 4 readings (which is 4000 pulses per mile) (how many rotations/mile for the driveshaft?)

 

That's about all I know.  I don't know where to start for mathing it, so I might just have to try 4 magnets and see what happens...


Edited by julianco, 23 January 2014 - 10:04 PM.


#43 julianco

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Posted 24 January 2014 - 03:06 PM

Assuming it is 5 pulses per wheel rotation, and the diff is a 3.9:1 ratio, this would give me 1.28 readings per driveshaft rotation, which is problematic.  

Is it really 5 pulses per wheel rotation though...

So I have a ~22.5" wheel diameter.

* pi = 70.6858 inches

 

a mile is 5280 x 12 for inches is 63360

 

63360/70.6858=47.5343

 

 47.5343 x X = 4000

 

4000/47.5343 = 84.149

 

Then divide this by 3.9 for the driveshaft.....

But 84.149 readings per wheel rotation seems really high, especially when 5 readings per rotation works for the Vanagon guys...


Edited by julianco, 24 January 2014 - 03:06 PM.


#44 ivans imports

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Posted 25 January 2014 - 11:32 AM

Can you use a axle tone ring on your drive shaft to give you the signal a tone ring could be pressed on and you could cut out teeth till you get the right #



#45 julianco

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Posted 04 February 2014 - 10:18 PM

I dropped the magnet count to 1 per rotation and bought an ultragauge which shows me RPMs and MPH read from the VSS signal.  

The engine runs pretty normal with 1 magenet, though it drops to about 650 RPM after stopping or dropping from higher RPM suddenly.  It never died, but wasn't perfect.  

 

The UltraGauge is reading pretty close to correct MPH, a bit slower, making me think that the 1.28 readings per rotation was fairly close to correct (though obviously unattainable).  So basically, it would probably do better on an axle.

 

ALSO, this made me realize that the '78 speedo is not perfectly compatible with the '89 D/R tranny, reading quite a bit faster than IRL.  That's mostly annoying because the odometer than is not correct either....

 

 

AND, today this happened and I don't know why.  

 

So I'm back to square one!

:banghead:  :banghead:  :banghead:  :banghead:  :banghead:



#46 julianco

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Posted 04 February 2014 - 10:32 PM

It seems like the best way to do this is to use the speedo cable inline style thing (like the Brantz BR4), which is pretty much plug and play, but I haven't been able to find one that fits into the subaru tranny (I think it's a M20x1.5 thread?).

What is the 3 way speedo cable tee ivans imports mentioned above?



#47 ivans imports

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Posted 05 February 2014 - 11:25 AM

Just found this in my 4x4 offroad mag Dakota digital speedo adaptors 1-800-852-3228 is for coverting electronic signal to cable signal this one was a ECD-100 these guys I bet would be able to help you



#48 julianco

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Posted 05 February 2014 - 12:32 PM

Man that thing is 300 bucks!  Also, it requires an electronic output from the tranny, which I don't have.  

I've called those guys before, and they also have some magnetic improvisation kits like this http://www.dakotadig...prod/prd109.htm

 

and a chip that allows you to adjust the input here - so my 1.28 per rotation could be ajusted (but it's good enough)

http://www.dakotadig...prod/prd126.htm

 

and the cream of the crop, a gps speed sensor which creates a pulse in accordance - super dope, but $200.

http://www.dakotadig...prod/prd837.htm


Edited by julianco, 05 February 2014 - 12:34 PM.


#49 julianco

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Posted 05 February 2014 - 06:24 PM

ivans imports - First of all, thanks for all of your input.  I appreciate the help.  

Have you been able to find those three way speedo splitter deals?  I've been looking and can't seem to find them online.



#50 ivans imports

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Posted 06 February 2014 - 11:02 AM

They came on early dodge vans with cruise 73-80






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