As some of you might recall, I had a catastrophic engine failure 2 summers ago coming back from Sharks In The Badlands. I thought the engine that failed was an S4 engine built by Marcus Hutchinson back in the day, according to the conversations I had with him, so I bought an 89 engine from Harvey C to replace it. Turned out that I had an 85 engine with S4 parts which was using 85/86 LH/EZF. So, I either had to source S4 computers and such, or go aftermarket. I chose aftermarket and went with VEMS, using the 89 harness that came with the engine. Unfortunately, due to my own inability to figure out VEMS, even with a tremendous amount of help from Colin J and Hans, and others, I was never quite able to get the VEMS to work with this setup. Nothing wrong with VEMS at all, just my own incompetence. So, I have decided to go back to a stock'ish setup.

Here is my issue: I have a supercharger, so I installed larger injectors. I will need to sharktune a PEM to reflect that. Speaking with Hans, it seems I need a diag port connection for the sharktuner, but the 89 harness doesn't seem to have one. From what I can find, the 12 pin diag connector was replaced with a 19 pin connector and was moved from the LH/EZK area to under the amp cover by the passenger seat. Does this sound correct, and what are my options with this setup?

 

That is correct...the diagnostic port and location changed.
Use an '87 or '88 wiring diagram and add in a 12 pin connector...the wires you need should be already be present in the '89 harness.

 

Ok, that seems to be the consensus suggestion. Digging out the wiring diagrams and taking a look.

 

Obviously, using an '87/'88 injection loom would be the easiest solution.

However, looking at the Sharktuner plug in for the '87/'88 models, there's only 7 pins used for operation,
so you will only have to "find" 7 wires, instead of all 12.

And some of those wires are present in the '89 loom, coming into the car through the "V" plug.

Shouldn't be too tough....

 

I found this list of pins and where to connect. Would you suggest tapping into the ones on the V connector wires and the others directly on the LH/EZK wires, or tracing them all back somewhere in the harness?

 

The '89 diag port has 10 connections (the '88 has 9) in each case one of the pins is ground.

Anyway for the Sharktuner you probably only need a small subset of these I'd contact John Speake about which ones minimally.

On an '89 diag port these are:

1. - Airbag Hazzard Light (Airbag)*
2. - Empty
3. - Locking Differential Function (Digi-Dash)*/***
4. - Empty
5. - Diag On/Off (Digi-Dash) */***
6. - Empty
7. - L-Diag
8. - K-Diag
9. - Empty
10 - Ground (MP V/GP V)
11 - Empty
12 - Fuse 25 output from (30)**
13 - Fuse 41 output from (15) **
14 - L-Diag
15 - Malfunction Indicator Lamp (Digi-Dash)*/***
16 - Empty
17 - Empty
18 - Empty
19 - EZK Pin 14

* I don't think you'd need these for SharkTuner (I'm not an expert though)
** probably don't need these power pins either.
*** You probably don't even have these sources

Alan