New to Mustangs from Central VA

General karthief said:

I would think there is something up with that, first check if the CEL bulb is good.
That may be a hint. What else was rigged.

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It was working because when I drove the car home because it came on for a few seconds at one point. I thought it was related to the idle problem or bad fuel, etc. But the light did illuminate, so I don't think it was disabled.

AeroCoupe said:

Go to the link I posted about pulling codes. You can do this with a test light.

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You'll love this. I went to find the OBD1 connector and it wasn't there. So I removed the passenger side inner wheel cover and found the wiring for the connector had been capped off and put in the wheel well. It was at least capped off neatly.

Lets assume the wires are still functional. Can I still perform this test by tying the right 2 wires together? Does anyone have a diagram for how the OBD1 connector was wired so I can figure out which two wires I need?

Edit: I see the linked page has the diagram further down. I'll see if I can uncap the wires and get this to work.

So it turns out the OBD1 Connection port has not been capped off. I found it on the driver's side between the battery and the fuse box, under the windshield washer fill. But it doesn't match the wiring diagram that was linked above.

-There are only 3 wires going into the OBD1 connector: green, black, and orange with white stripe. Both green and o/w have 12 volts.
-The self test connector has 2 wires, both black with white stripe.

I was not able to make anything work pulling codes. If anyone can offer some advice or suggestions on next steps, I would really appreciate it.

AeroCoupe said:

Other thing is I thought your test port was behind the passenger side strut tower. Makes me wonder if someone extended the wires.

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Correct. According to everything I read, it should be behind the passenger side strut. So the wiring is definitely not the same as stock. So I'm really not sure where to go from here.

Update: I thought I had checked all the fuses related to the CCRM/EEC, but I had missed one. Under the dash, Fuse #18, was blown. I'm not sure whether this fuse runs to the CCRM or the PCM. Either way, it was blown. So I put a new one in, and it immediately blew that one too.

What does this tell me? A short somewhere? Where should I start looking?

I was finally able to track down my wiring issue. I ordered the EVTM from Summit. Thank goodness there's a company that still prints them for these vehicles. I looked on Ebay and its ridiculous what some people are charging for a beat up old used one. The new one was only $40. Anyway...

After tracing the wires on circuit 18 around and lots of testing with a multimeter, I was able to find the issue. The prior owner had installed a BBK cold air kit. One of those that puts the filter in the passenger's side fender. When they installed it, they pinched the wiring between the fender and the air kit assembly. After enough years of rubbing, it finally cut through the insulation on a few wires and was causing a short to ground on the Red with Green stripe, which feeds into Pin 13 on the CCRM.

The wires themselves were fine, so I put some electrical tape on and I think that will be all that is needed. Now, I just need to figure out how to make sure everything stays where it should when I put the CAI back together.

@AeroCoupe - many thanks for hanging with me and for your advice!

I still have quite a bit to do on the car, but that was a big relief to solve that one. I still haven't actually fired the motor up because I have some other things taken apart that I'm working on. But now when the key is turned the Run position, the fuel pump primes (that was music to my ears), the Check Engine light comes on as it should, along with the other warning lights on the dash. So definitely a victory!