On Friday my 6 cylinder 66 started acting up. It would turn over 1 time and then cut off. I have had carb issues in the past so I cleaned up the 1100 real good and made sure everything was good (spent hours on it and nothing helped). It would turn over but not stay on every time.

Finally read online about someone having a similar issue and it was the switch assembly. So I ran a wire from the coil to the battery, cranked it up and it stayed on and ran like a champ. Pull the wire off and it cut right off.

I went to the parts store and got a new ignition switch assembly (not the lock cylinder but the piece behind that). Unfortunately it didn't help. The weird thing is with the new one, the instrument cluster gauges didn't move and the radio didn't come on. The engine still bumped over in the start position but that is it.

Could I still have a ignition switch problem and just got a bad one from the store? What Else should I check? Could the starter solenoid be bad (I know where it is but when I have had issues with those the car won't start but I have some weird electrical issue where it won't stay on)

 

Hi,
OK let's define a little better....
The engine cranking, is one system, the engine firing and running is yet another.
When you state "It would turn over but not stay on every time." Is the engine cranking, firing and running, then die?
"Could the starter solenoid be bad" ...The solenoid does connect the battery to the starter and is needed for cranking the engine. Within the solenoid is an ignition circuit which supplies voltage to the coil for ignition and running. Now, the ignition switch can be at fault, as it is responsible for "cranking", "firing", and "run", in concert with the solenoid, coil, and
distributor ckts. What is the general condition of the wiring systems.
So, I'll ask again...." Does the engine crank, fire, run, then die?"
So, do you have a shop manual or wiring diagram for your year?

 

Kenash,

I think you understand me. Yes -> "Is the engine cranking, firing and running, then die? "
Every single time it fires like one time. But if I hot wire the coil it runs like a champ.

No I do not have the shop manual.

Just so you know, I have drive this thing every day for months. It has cut off a couple times where I cut it right back on which looking back now may be this same issue.

Are you saying I should look at the solenoid also?

 

OK,
I would say, if you can hot wire it, I would start checking the ignition wiring ckt. But, you really need a wiring diagram (showing color codes) so you can, logically, chase the ckts and their terminations. You could have a simple break or spade connector fault. Someone may chime in with a link to a diagram. I would highly suggest a shop manual and a separate specific wiring schematic be in your future.
BTW, I don't like throwing money at parts without proper diagnostics. But, a solenoid ckt failure could be a possibility. This being stated, check that termination point. There should be 12Vs between the stud and the lead.
How are you "hot wiring"?
Good Luck.

 

I see this.
http://www.hammar.dyndns.org/~djhamm...66/66ignit.jpg

But how do you even start?

How do you check the solenoid? Measure voltage across ...??

Thanks again.

 

Hi,
OK, good start!
Reference the schematic.....
The solenoid has a BAT and Ground terminals (both large terminals) and two smaller terminal posts "S" (starter) and "I" (ignition).

The ignition switch has 3 terminals, "C" (charging), "B" (battery), and "S" (starter)
Become familiar with these terminations.

Notice the "I" terminal of the solenoid, feeds the "B" side of the coil (reference ckt 262 /16) Disconnect the main plug (at firewall), Using a VOM check for continuity between the Brown (262) and the RED/green (16) and "16"'s termination on the "B" side of the coil.

Ckt 32 (Red/blue) is the starter side ("S" on the solenoid). As you mentioned this side is working as evidenced by the engine cranking. So, the fault is in the Ckt 262/16 ignition side ("I" on the solenoid) either a wiring issue or internal solenoid issue.

When the key (ignition SW) is turned to crank, full 12Vs is connected to the starter (S) terminal. It pulls in the solenoid connecting the full cranking AMPS of battery to the starter, at the same time a full 12Vs ("I" side of the solenoid) is flowing to the "B" side of the coil, or should be through ckt 16 (Red/green).

So you now have cranking and power for the coil to do it's thing. You will need a an VOM or a ckt test light to check this but, look for breaks in Ckt "16".

At the ign. SW, after the engine starts, the ignition SW is in the "run" position ckts 16 to 16A kick in to reduce (resistor wire) 12Vs to 6-8Vs to the coil, as a full 12Vs is only provided to for start-up.
Basically, it gets back to, if you are in the "run" position and the car dies after starting check the resistor ckt (16/16A) and the notorious pink wire.

Does this help? I'm drawing on memory power, but, this should give you a feeling of how to approach it.

 

Here is what I have done and what I know now (still isn't fixed but im getting there).

I tried a different ignition switch but it didn't automatically work then. I have access to another mustang and I tried the starter solenoid off of that one and put it on and it didn't make it work then.

What I did figure out when trying everything though. Was I got it to work (without the wire to the coil) with all the original stuff.

I think I just have a loose wire somewhere. Still not sure how to figure out where. Or what to do. If I put everything back together and it runs for a while I may still have this issue again.

Should I try to narrow down where the loose wire is and how?
Any other advice?

 

OK. You have a diagram. Check all of those connections. Starting with the ignition. Do you own a VOM ("V"oltage "O"hm "M"eter)? Use it to check continuity between the important points. This is the only way to find it. Throwing money at it won't cut it!
Good Luck!

 

Is power off or on when I check continuity?

You say start with ignition. Does that mean the back of the ignition switch to those other points? Say from switch assembly to those junction boxes?

If I find one that does not have continuity do you cut it out and replace it?

Is the issue these wires get old and break?

 

Hi,
Yes. In continuity, your are making sure, from point "A" to point "B" there are not breaks. Therefore, no power!

If you start with the Ign. SW. you check each of the leads each of their termination points along the way to their end destination.

You ask, "do you cut it out and replace it?" It's a given, if you find there is no continuity between "A" and "B", you can insert a test wire between the two points. If the ckt. works, then you would have to insert that wire into the bundle, make sense?

Yes, they (wires and cables) can, in themselves, become brittle. The spade connectors can develop resistance, resistance decreases the current flow, not to mention heat is created. In the case of ground wires, it's imperative, to have a clean connection to body/chassis. Grounds have been known to be the most disruptive known cause of electrical malfunctions. Every engine should have a clean ground(s) to the chassis.

Hope this helps..