Butchered wiring, relay, ecu, ignition!

[MEZZZ]

Well, here is the latest in my car wont start journey

Stephen,(sblake01), you are up to speed and I wont lay everything out up to this point, I am hoping you can look at some photos and clue me in.

First, a little background. I pulled out the carpet, etc, to start redoing thre interior, Por15, dynamat, new carpet, etc. There was a wire running from under the driver part of the dash, clear speaker wire. It ran from behind the ecu panel and continued back towards what at the time was the tool box. I now remember (months later, it went inside the vinyl around the inside of the dogleg area directly underneath the speaker. I thought at the time it was some rigged wire going to the speaker and when I gave it a light tug it popped out from behind the vinyl, not connected to anything and it had a wire nut on the end. asically, it was just laying inside the vinyl covering.

Fast forward to now and my car wont start. I have been trying to educate myself about the relays, etc, looking at the FSM and FI manuals. Today, I decided to try and trace this mystery wire as I figured out awhile ago it had nothing to do with the speaker. I removed the ECU and took off all the electrical tape.

Here are some photos of what I have found.

I am assuming this is the connector for the power relay. For some reason, the red wire (coming off the battery) has been spliced into blue.

I once again, am assuming this is the fuel pump relay, once again, the red wire is spliced.

Here is the mystery wire that was originally wire nutted off. It appears to be spliced at the connector coming off the connector that has 4 green wires and a black, it is spliced onto the black. Then the other side, is spliced into a black wire coming off the 35 pin ECU connector.

A closer view. I put a circuit test light to it and both ends of the speaker wire are hot. This wire was hanging out of my door one day (still wire nutted) and I went to roll the car out of the garage and ran over the wire and it got broken off at the door. Therefore, it is no longer connected.

Any ideas? On a side note, I bought a noid light today and have nothing at the injectors. Could this all be related? Thinking back, maybe when I rolled over and broke this wire is when my car wouldnt start but I cant be positive. I dont want to simply "nut" these wires back together to try. My next step is to figure out where the black wire is connected to the ECU harness.

[sblake01]

Where did the other end of the 'speaker' wire connect? I'm giving this a lot of thought but my expertise(?) is with the a 78 280 and a 79 810 which is different from the earlier cars.

[MEZZZ]

Stephen,

Right now it does not connect anywhere, it is about 12 inches long and just hanging. Originally, it went along side the drivers door and behind the vinyl panel behind the drivers side door, below where the speaker is. It was not hooked up to anything at all, it had a single orange wire nut on it. I am thinking back, my 47 yr old mind trying to remember, but I think the wires were twisted and nutted, in effect, making a connection.

I am wondering if this may have one time gone to some kind of an aftermarket cutoff switch perhaps? It makes no sense to me that it ran behind the seat and was nutted off back below the speaker. I looked behind the vinyl panel and see nothing back behind there, only what appears to be the wire for I am assuming the power antenna going into about a 2 inch diameter hole.

The connector it is coming off is pictured below.

4 green wires and what appears to be a black wire and that is where it is spliced, although it appears to be blue in the diagram. That blue wire appears to go to pin 1 of the ECU. Then the other side is spliced into a black wire to the ECU. I could attempt to trace the wire to the pin in the ecu connector.

[MEZZZ]

I took a break from this problem the past couple days and worked on other projects. I installed the Speedhut overlays I bought last winter. I had bought an extra set of gauges last winter as well and used them in the upgrade. I did the small gauges first and all went well but had issues with the tach/speedo. I had a 1/2 dash cap on the car and couldnt remove the tach/speedo. I tried to carefully take the cap off but the P.O. must have used a whole tube of silicone on it. I had to end up breaking it off in pieces (already ordered a full cap to replace it).

Anyway, I looked at the car yesterday and noticed about a 1/2 inch diameter hole in the vinyl below the speaker panel. I noticed the hole in the past but figured it was missing a plastic rivet. Then I looked at the pass. side and noticed no rivet or hole. I pulled the piece back a bit and took a look behind it, the hole in the cover is right over about a 2 inch hole in the bodywork, this is where I originally found the nutted "speaker" wire.

By all appearances, I am thinking there was a kill switch mounted back there at one time. Since the wire was nutted together, it was making a connection and since I ran over the wire a few weeks ago breaking it, no connection is being made now. I fought off the urge to twist both sides of the speaker wire together and see if she fires, I would hate to fry something

Stephen, I value your opinion as always.

[sblake01]

If both ends of the 'speaker' wire are hot, two things. One, it's not a speaker wire in that I've never seen a speaker that takes 12 volts to both terminals and two, if both ends are hot, putting them togehter won't fry anything. The 'kill switch' scenario makes sense to me. And if that works, you actually should remove that wire and splice the black wire from the connector back to the black wire from the ECU.

[sblake01]

Just a follow up: I think the black wire with the speaker wire spliced into it is the blue wire in the diagram and that's the signal wire. I won't run without a connection there.

[MEZZZ]

Wonderful! Thats the answer I was looking for. I had thought the same thing but wanted to get your valued opinion. Hell, maybe its not speaker wire, it could be lamp cord When I got the car, there was a "ground" running from the valve cover to the strut tower, it was a piece of 12/3 outdoor

I will go ahead and give it a try and let you know the outcome. Thanks!

[sblake01]

That should read: 'tachometer signal wire'.

[MEZZZ]

That should read: 'tachometer signal wire'.

I'm lost, what should read tachometer signal wire?

Anyway, an update. I got everything back together, ECU, etc. I took the "speaker wire" and spliced them back together. Put the battery cable back on, put the keys in the ignition, crossed my fingers..turned the key...

IT FIRED RIGHT UP!!! THANK YOU STEPHEN!

The billowing black smoke is gone from the last time I cranked it over as well. It seems to idle much better as well. I had someone look at it earlier this week and he noticed that the EGR valve was froze and he freed it up by pushing on it until it popped free. Once I started the car, I pushed up on the EGR and the idle went rough so that might have been part of the problem as well.

I did replace the wires, plugs, rotor, dist cap, ignition coil, battery, injectors, fuel filter, and assorted vaccum lines as well, so that might have helped cure some of the problems. It was missing badly before and it seemed much smoother.

The guy that looked at it told me my spark wasnt a nice blue one and suggested I replace the pickup coil in the distributor, I just got a call from the store and it is in so I will go ahead and swap that out (I've read up on the subject) and then get back to where I was 3 weeks ago and adjust the timing.

One thing I did notice is it seemed to be smoking a bit from the exhaust. Not the billowing black as before but more of a white. But hey, at least it is running and I owe you a huge amount of gratitude! Thank you again!

[sblake01]

I'm lost, what should read tachometer signal wire?

In my post (#6) I said:

I think the black wire with the speaker wire spliced into it is the blue wire in the diagram and that's the signal wire.

The statement should have read:

I think the black wire with the speaker wire spliced into it is the blue wire in the diagram and that's the tachometer signal wire.

I'm glad that worked. Like I said, I have a 78 which is different from the 75-77 in many ways when it comes to wiring. But when I looked at the 77, combined with your explanation of how that extra wire was hooked up, it dawned on me that the car wouldn't run because breaking that wire interupted the continuity in that circuit.

[MEZZZ]

Thats pretty much what I though as well. I do know that at one time the mystery wire was nutted together. After I climbed under the dash and pulled off the electrical tape to get a look at what was going on, coupled with the hole in the side panel where I originally found the wire, it dawned on me the connection was broken.

I now remember that that wire was hanging outside the car about 3-4 feet. I also remember backing the car out of my garage (my wife doesnt like the fumes ) to try and start it and running over and breaking that wire. Obviuosly, it didnt dawn on me at the time that I just killed it.

Regardless, thanks again, Im off to the auto parts store to get the new pick-up coil and attempt to tune this thing now that its running again. Its back to work Monday and starting tonight I have to spend the rest of my week off mending fences with the family with a weekend trip to Gatlinburg, Tennesee

[wal280z]

4 green wires and what appears to be a black wire and that is where it is spliced, although it appears to be blue in the diagram.

Mark and others - The colors on the diagram are what the FSM indicated them to be.

I did not verify with an actual harness at the time I drew the diagram - talk about a hornet's nest!

On my spare harness, the FI Relay connectors look the same as yours, sans the red wire splice.

Wayne