legacycentral bbs

There's a rub with the dogbox I was going to use.

There is no speedometer scroll machined onto the 3/4 cluster.

So I won't have any speedometer. No Speedometer means no VSS.

No VSS means problems with other things.

Would it be possible to fake a VSS signal to the ECU?

Could I use the signal from an ABS sensor or something and convert it to a speed signal to feed the ECU?

I could put a post-it-note in place of the speedo with RPM/Gear and just drive by that.

Ideas?

Umm...it won't pass inspection that way (with the note). Besides, I don't think I would recommend that.

Satisfying the ECU will be easier than making the speedometer itself work, since all you need is the electrical signal... I kinda like the idea of starting with one of the ABS sensor signals, especially if you've disabled the ABS already anyway. You could probably just use an HIP9020 chip to convert the signal from the reluctor to a square wave; if necessary, you could then use a counter to divide the frequency.

You might get away with just conditioning the tachometer signal and using it, but then radiator fan control would act weird.

The stock speedometer is mechanical, though. I don't know if you could switch the speedometer out for one from a later model gauge cluster or not; more likely you'll have to use some kind of aftermarket speedometer that can use the signal from the first paragraph.

Manarius - The car would never need to pass inspection again anyways.

The car will be street driven VERY infrequently. It would spend most time at the track.

It may end up coming to the point where I simply ditch the stock gauge panel all together, and replace them with some Autometer bits. Just use some sheet aluminum, and drop in a tach, speedo, and whatever gauges I need. Then some LED's for various lamps (CEL, etc). SHOULD be easy, but nothing ever is.

Vikash - Sounds pretty simple, though I don't understand electronics as well as I would like to.

oh, and did you get my last e-mails?

good luck finding one of these but I know for a FACT that they make these little boxes that go in line with the speedo cable and have a VSS output. used for adding in car navigation systems to cars older than 95 or something like that.

Phil - When the time comes I'll try to give you a hand figuring it out. The HIP9020 is hard to find (it might be obsolete by now) but would do the job very well and is easy to use.

Mike - But he would need the reverse -- he will have no speedometer cable.

I would say maybe look into a Digital speedo, one that uses a pickup off of a wheel (just like ABS), and then somehow convert that signal...


Or figure out how to put a Speedo drive in the Dogbox?!?!

My only comment is that you definitely need to find some way to make the ECU happy. With no speed signal to the ECU, the car does weird stuff.

oh I should read the post fully before I respond next time I actually did find a gizmo searching google that took a vss and turned it to a speedo cable for speedometers and such.

http://www.abbott-tach.com/cablex.htm

For searchability's sake, the problem you describe might throw a code 24 and/or code 33, both of which, as I'm experiencing, are related to the vehicle speed sensor.



I've recently added the speedo cable since the swap, but I'm still getting the same codes. I've had them cleared by Jake at his shop, and they return within 24hrs.

Being a turbo now, this seriously impacts my daily drive. (I'm serious!)

My speedo works, fine, and registers correctly.

The vehicle speed sensor is an input, no?

Tristan, what was your original setup? AWD AT? Did you just sitck the speedo cable end in the MT cable?

Do you have access to a laptop to use Vikash's scantool to view the output from the ECU?

Legacy777 wrote:My only comment is that you definitely need to find some way to make the ECU happy. With no speed signal to the ECU, the car does weird stuff.

He ain't lying! My car was doing some funky stuff when my speedo cable went.

Yea, the 3rd/4th gear cluster on the output shaft has no speedo scroll.

I was thinking of getting a WRX gauge cluster and transplanting that into my dash. Still converting the ABS signal to a VSS signal, but having that go also to the gauge cluster.

I haven't really thought much about that, but it sounds like it may kind of work since the factory WRX speedo is electric.

We'll see. Thanks for the input.

The car won't do what I want if it doesn't know how fast it's going. The car will see drive-way duty for a while until the motor goes into it and I figure out the wiring for engine management. Still has to drive though on the current motor.

Phil, the other option is to create a circuit that has an alternating 0 and 5 v signal. I don't know if the ECU would eventually figure out that it's not the VSS signal and throw a CEL. On the torque chip, they modified the VSS. It basically limited the speed signal to like 45 or something, but it oscilated between lik 44, 45, 46. I don't know if it did this just because, or if it did it so the ECU wouldn't learn around it and throw a code. Also, I believe it did go to 0 mph when the car was stopped.

So the VSS is only to see that the car is moving, and that's ALL!?

Wow. Low tech we are.

That might be another option I'll look into.

All my parts were working and in good condition when I swapped them.

Josh, I'm running an ej20g bottom end, with stock legacy turbo everything.

Josh, I'd like to put in a photo to this thread, can I email it to you? Where to?

Just got the codes checked out again, and from what jake tells me, the vs isn't reading at all.

So, I hear I gotta replace the deal on the back of the speedometer cluster.

Or. . . .


?

You could fake the signal like I will be doing. You could do the analog to electrical converter since you have a stock transmission.

Hmm, I bet that would totally fix Matt's VSS problem too....

I wonder if you can do this AND keep a mechanical speedo? The problem with the ABS idea is that you'll lose ABS. I don't care, because I don't have ABS. You might.

BAC5.2 wrote:So the VSS is only to see that the car is moving, and that's ALL!?

Wow. Low tech we are.

That might be another option I'll look into.

Well....maybe...maybe not. The ECU may look at road speed for stuff like cooling fans or what not, however I don't have any data to back that up....so I'm just guessing. BUT, any of those chips out there that remove speed limiters....that's how they do it.

For the automatics, the TCU will use the VSS2 signal to control AWD....however that shouldn't be an issue with yours since it's MT.

tris91ricer wrote:Josh, I'd like to put in a photo to this thread, can I email it to you? Where to?

You can use the email addy in the email button below the post

Yea, I'll have a caveman manual transmission.

I just would like to know if Vehicle Speed matters, or as long as it knows if I am moving.

Eventually, VSS will be feeding a WRX ECU, so I'd need to know if it mattered to the WRX ecu also...