Engine keeps running T&C '77

[Koronetti70]

Hi,

I have this interesting problem and since I still don't have the FSM, I'm going to ask your help. I have a couple questions.

I have a 1977 Town & Country. These came from the factory with the Lean Burn, correct? It has been converted to Chrysler electronic ignition by some previous owner decades ago. I am pretty familiar with 1970 B-body electrical system but this feels like a huge mess compared to those.

Anyways, it used to work fine when I got it. Then it began to stay running when I took the key out from time to time. Sometimes it died if I turned the headlights on with the key out. After a while I couldn't shut it off no matter what I did. Disconnecting the battery doesn't help. I have to pull the ECU plug to kill it. No, it's not "dieseling". It just keeps running like normal even tho the keys are in my pocket. Turning the key to "0" definitely does something, as the blower motor turns off. What could be the cause?

I've replaced the ignition switch twice and I don't think that's the problem. I've tried adjusting it but that does nothing for me.


Second question. When I was messing around with the ignition wiring, I noticed that it doesn't have the ballast resistor "bypass during cranking" wire. The resistor only has the blue "run" wire and the coil positive wire on the other side. How come does this thing start perfectly fine??

 

[CBODY67]

There are several Chrysler Electronic Ignition system schematics online on the Internet. As to the wiring on the engine side of things.

I presume you realize that the actual ignition switch is on the side of the steering column, under the instrument panel. NOT where the key goes into the ignition key cylinder? Just mentioning this as a clarification of where the actual switch is . . . no more, no less.

I suspect you know what needs to be done, but are a bit unsure of what is what? Sounds like there might be some voltage "back-feed" that is messing things up. Possibly through a ground not being fully grounded?

Just some thoughts,
CBODY67

 

[MONC440]

Possibly through a ground not being fully grounded?

Agreed! Check your grounds first. If it didn't do it when you bought it, and if you didn't change anything, and it first started doing it every once in a while, now it does it more often or all the time I would say it is a ground issue. Clean you common ground points and see if it goes away.

 

[Vaanth]

Hi,

I have this interesting problem and since I still don't have the FSM, I'm going to ask your help. I have a couple questions.

I have a 1977 Town & Country. These came from the factory with the Lean Burn, correct? It has been converted to Chrysler electronic ignition by some previous owner decades ago. I am pretty familiar with 1970 B-body electrical system but this feels like a huge mess compared to those.

Anyways, it used to work fine when I got it. Then it began to stay running when I took the key out from time to time. Sometimes it died if I turned the headlights on with the key out. After a while I couldn't shut it off no matter what I did. Disconnecting the battery doesn't help. I have to pull the ECU plug to kill it. No, it's not "dieseling". It just keeps running like normal even tho the keys are in my pocket. Turning the key to "0" definitely does something, as the blower motor turns off. What could be the cause?

I've replaced the ignition switch twice and I don't think that's the problem. I've tried adjusting it but that does nothing for me.


Second question. When I was messing around with the ignition wiring, I noticed that it doesn't have the ballast resistor "bypass during cranking" wire. The resistor only has the blue "run" wire and the coil positive wire on the other side. How come does this thing start perfectly fine??

Something else is keeping power to the J2, Ignition RUN, circuit, or the J3 circuit, to prevent the ignition switch from disconnecting the power, if the switch itself is confirmed good. The circuits will require tracing to see where the cause exists.

A factory service manual, or wiring diagrams, should be obtained to use for tracing the circuits. Because this was an Electronic Lean Burn converted to conventional electronic ignition, those changes, and the manner in which they were done, for that must be considered as well. Those changes may not be the cause of the continuous running, at least not initially because it worked before. The factory service manual has the wiring diagrams for the small block C-bodies with conventional electronic ignition which can be used to compare to the Lean Burn wiring.

The conventional ignition is simpler than the Lean Burn system, and relatively straightforward to convert, but depending on how well, or not, that conversion was done can complicate troubleshooting. Both systems in 1977 still used the four terminal ballast resistor. If that was replaced with a two terminal ballast resistor and four pin electronic control unit (ECU), the overall wiring is even simpler, and the auxiliary side of the four terminal resistor references can be ignored if that wiring and connections were removed properly. Or if the four terminal resistor remains, with a four pin ECU, the associated auxiliary side wiring can likely be ignored, but still checked.

Starting in 1975, on some models and all by 1977, the direct Ignition START feed was removed from the ignition switch, and moved to join at the Start (S) terminal of the starter relay. On the 1977 C-bodies, the junction of the ignition START feed with the ignition START side of the ballast resistor was moved from the resistor terminal to the six-way disconnect in the engine wiring harness.