julianco

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...

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...

I've hijacked this thread, but thought the topic belonged in this forum so.... To recap, I have 5 magnets on the driveshaft being read by a hall effect sensor on the tranny. With the Vehicle Speed Sensor wire disconnected, the car runs more or less normally unless I let the RPMs drop too suddenly, and then the engine will stall. I can baby it, and get it to idle, though sometimes doing this, it goes into what I think is "limp mode" and it runs rough, shudders, has no power etc. Turn it off and back on, and it's back to normal - running normally and dying after dropping from higher RPMs. When I hook up the VSS wire, the car runs perfectly until roughly 33mph. It doesn't want to die at stops and seems to run stronger while driving (might be my imagination). But when it hits 33, it seems to cut spark. If I keep it over 33 (going down a hill) the car will die. If it drops below 33ish, it will start firing again. This seems to me like I have the wrong number or readings per rotation so I'm trying to figure out the math as I'd prefer to bust off the magnets and glue them back on only one more time if possible - skipping the trial and error. I'm pretty sure that the VSS wants to see 4000 pulses per mile. The vanagon/EJ swap VSS kit which I'm using a part of, uses 5 pulses per wheel rotation. I'm pretty sure the rear diff ratio is 3.9:1 like the brats? My wheel and tire diameter is ~22.5" which I think give me about 47.5343 rotations per mile.. From here, I'm a bit stuck. Any ideas?

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...

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.kjmagnetics.com/proddetail.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.

A little pricey. PM'ed

Also a roof basket if anyone has a line on one of those...

Front carpet for 1978 Leone. I think most first gen carpets would be compatible, but not sure.

Black would be preferred.

Back late to this, but CVJ in Denver made some up that are going in tomorrow. I was told that the OReilly Chinese ones don;t hold up to well. Any experience here? The CVJs look great.

OK. Thanks for the info! I've been spending too much time on the Subaru and other work is catching up. So I have to take a break on it for a little bit. I am leaning towards the more simple aftermarket gauge option along with an oil pressure, and maybe eventually tach. It should just wire right up to existing sender right?

I have a 97 ej22, 78 Leone, 89 GL 5spDR So no tach, and no oil pressure gauge in the '78, but I was hoping to tie in the temp gauge. I thought it might be possible to get some reading and then adjust it with some 'lectrics, but when I plug it in, it shuts down the fuel level and charge light (same circuit I suppose) and it also doesn't work. So I'm thinking of doing some custom gauges. Temp gauge is the most important, but I'd like to have oil pressure and tach -- any recommendations on what to buy? I'm also thinking about finding a junkyard impreza dash and maybe finding a way to mount the gauges from it up...

I'm in Colorado on the front range and would love to get something locally. It is a '78 Leone I'm shopping for.

Looking for '78 compatible front axles.

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

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

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.

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.

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.com/index.php?dispatch=products.view&product_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?

You have a line on those?

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?

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.

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.

Can I wire this right to the ECU? or do I need something to work with the signal? This article http://www.speedview.co/forum/Thread-Adding-a-VSS-output-to-a-Mechanical-Speedo-reed-switch?pid=12#pid12 makes me think there's more to it than just the reed.

Yeah, so far what I've found is that the signal needs to be square and between 0-5v. 4 readings per rotation of the speedo cable. I've isolated the reed switch from the GL speedo. It sits right behind the disk on the backside. Now can I just take this little pickup guy and put it behind the same part on the '78 speedo? Or is there something on the spinning disks/magnetic dealy that is necessary for the reed switch to work? In the assembly: And pulled out: Lead on the left is + and on the right is ground ... right?