simulating a tach and a vss wire

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=98751
Printed Date: May 16, 2024 at 6:19 PM

Topic: simulating a tach and a vss wire

Posted By: 8520
Subject: simulating a tach and a vss wire
Date Posted: November 07, 2007 at 11:21 PM

Honestly I'm not sure if this is the best place for this question, but I figure that most of the people that are familiar with working with tach wires etc would be those lurking in this forum. If it needs to be moved, feel free :)

That being said, here's what I'm attempting. I've been working with my interior lighting and have changed the interior lighting to all red with led's. The gauge cluster looks cool and all but I'd like to add something a little different. What I'm trying to figure out is how to simulate a tach wire and vss wire so that upon ignition my tach needle would peg and then drop back to 0 (like this audi does - https://www.youtube.com/watch?v=b4Wckl5dIBI).

From my understanding of tach wires, they "work off of" ac voltage but am unsure about how to recreate this. As for the vss, I would assume it runs off 12vdc, but am not positive.

If it matters, the car is a 99 civic ex (for all intensive purposes anyways).Thanks for any help!

Replies:

Posted By: rfwave
Date Posted: November 07, 2007 at 11:31 PM

electronic vss in dash ?

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Posted By: 8520
Date Posted: November 07, 2007 at 11:35 PM

I am unsure. I know the vss is on the tranny and has 3 wires.

Posted By: howie ll
Date Posted: November 08, 2007 at 4:20 AM

If you look at the 3 wires from the trannie, 1 will go live with ign., 1 will go to ground and the third is the one you want for VSS. You left one very important thing out, make, model and year vof vehicle?

Posted By: 8520
Date Posted: November 08, 2007 at 2:35 PM

howie ll wrote:

If you look at the 3 wires from the trannie, 1 will go live with ign., 1 will go to ground and the third is the one you want for VSS. You left one very important thing out, make, model and year vof vehicle?

I actually listed at the end of the first post. posted_image

Car is a 1999 honda civic.

Posted By: profuse007
Date Posted: November 08, 2007 at 3:13 PM

Speed Sense BLUE/WHITE 4000 (AC) PASS FIREWALL 3 PIN CONN TOP TRANSAXLE

note the 4000 is the signal rate. I am not familiar w/ VSS but check in cruise control sectino.

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Houston,TX
"The two most common elements in the universe are H+ and stupidity" (Ellison).

Posted By: 8520
Date Posted: November 13, 2007 at 9:59 PM

Man this thread didn't do so hot ha ha.

I looked in the cruise section, but didn't find any useful info :S

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Lots of diamond audio and clifford junk :P

Posted By: Mad Scientists
Date Posted: November 14, 2007 at 5:56 PM

So, you're saying that you want to generate a VSS and Tach signal when you start the engine to force the speedo/tach to full sweep?.. Have you considered what the PCM is going to think when it sees that data?.. I think it's a good possibility the PCM will doodiee itself when it sees that.. maybe only a check engine light, but the possibility of more serious problems.

I'd be looking at the signal wires from the PCM to the gauges - modify there, not inputs to the PCM.

Jim