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moku 01-10-2013 07:41 AM

CJ dash swap VSS problems. NEED HELP!!
OK, So I put a CJ dash in my '95 YJ with a 4.0L engine. Because I wanted to use the mechanical CJ speedometer, I used a speedometer gear pinion housing assembly from a '91 YJ - which provides a connection for a speedometer cable and a 2 wire VSS connection.

The Jeep 4.0L originally had a 3 wire VSS. Using the information from several Jeep forum postings, I connected the WHT/ORG (pin 47) wire and the BLK/LT BLU (pin 4) wire to the new 2 wire connection.

The Jeep starts and runs fine, but dies almost every time I come to a stop. I assume my VSS is not sending the correct signal to the PCM for the idle speed control.

Does anyone know if I used the wrong 2 wires, or if there's a way to fix this?

Thank you in advance!

Mark05059 01-10-2013 07:58 AM

JeeperDon 01-10-2013 07:58 AM

You're assuming the '95 ECM uses the same pulse config as a '91. The '95 uses a gnd in, and a +8v I believe from the ECM as power, a signal out (orange). I know the +8 part is not critical as I used a simple IGN supplied +12 when I did my swap. I'd look at a '91 FSM to better understand that year VSS system in detail. Dakota Digital (.com) may be able to help too, maybe their SGI-5 unit (I think thats the speedo one, might be the SGI-8).

Que89YJ 01-10-2013 08:08 AM

It does use the same VSS signal.
This thread:

moku 01-10-2013 10:58 AM

Thank you for all of the links. I had read most of those previously and I wired mine based on those posts.

However, I still have the problem.

Any ideas?

moku 01-10-2013 11:20 AM

Oh yea, I also checked the codes and I'm not getting a 15 for the VSS. ??

To clarify, I have the signal and ground hooked to the vss/speedo combo. I had read to leave the 8V power off.

Que89YJ 01-10-2013 11:24 AM

How are you checking the codes without the CEL? What codes do you have?

moku 01-10-2013 12:54 PM

I wired the check engine light to the "emergency drive" light on the CJ cluster. I have a posi-lok cable installed and didn't care whether or not the shift fork was moved or not.

I got the following codes:

12 - I've disconnected the battery a lot to do wiring
33 - I don't have A/C so I assume it's showing that as an open circuit?
55 - end of codes

Why J? 01-10-2013 08:11 PM

Here is a thread that walks throught using the 2 wire:

But I would think that if you hooked it up in correctly then you would get a CEL.

moku 01-10-2013 08:41 PM

Awesome, I hadn't seen that sight yet! Thank you. I'll check the wiring tomorrow and see if I have them wired the same. Another forum post mentioned it didn't matter which side the ground was on, and I was a bit curious about it too. I'll post back tomorrow what I find out. Thanks again!

moku 01-11-2013 06:09 PM

I was able to switch the ground and signal wires today, but didn't get a chance to see if it works correctly. I'll report back when I do. Thanks again.

Que89YJ 01-11-2013 06:12 PM

Battery reset it too.

moku 01-11-2013 06:14 PM

OK, I disconnected the battery when I rewired it earlier today and haven't hooked it back up yet.

I don't know how the whole VSS system really is supposed to work, so I'm curious what resetting the battery will do?

Hopefully it works though!

Que89YJ 01-11-2013 06:16 PM

Zeros the cal in the ecu and clears any codes set.

moku 01-11-2013 06:19 PM

What do you mean by "zeros the cal"?

It sounds like you have a good handle on how this works... Which is great!

The time now is 08:26 PM.

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