1973 Dodge Monaco Ignition Switch Tilt Column

1970FuryConv

Old Man with a Hat
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I have a 1973 Dodge Monaco coupe, 360 V-8, 727 trans, 5 prong ECU with dual ballast resistor (IOW, ORIGINAL IGNITION SET UP). I have tried 2 different dual ballast resistors and replaced my original distributor with a rebuilt unit from Halifax hops.

My problem is that when the engine is cold, i.e. sat overnight, the engine doesn’t start when I turn the key to the start position. It only starts, as I release the key from start to run. By contrast, when the engine is hot, the car starts instantly in start position. Either way, the car runs excellent as soon as it started. It’s a pleasure to drive.

Ignition Switch: battery voltage going into the ignition switch is 12.45 V. Cold resting voltage at the battery itself is 12.57 V, so there’s almost no loss through the bulkhead connector. By contrast, when the key is turned to START, the brown start wire has a voltage of 10.9 V at the ignition switch which yields of voltage of 10.6 V at the ballast resistor and coil positive during cold start. (These voltage readings increase to 11.2 when the engine is warm)

My question is: has anyone experienced a tilt steering column ignition switch performing poorly when the engine is cold and perfectly once some current has been flowing through? Dirty Contacts?

As I understand it the tilt columns are made by Saginaw, so they are an adapted GM product.

My 2nd question is: what is the correct Delco part number for this ignition switch or is it a Mopar part number?
Thanks. All help appreciated.
Ignition Switch
PXL_20220118_223427826.jpg

Tilt Column
9.jpg
 
You probably have dirty contacts in the ignition switch. If you are trying to source an OEM unit, take the numbers off of your existing switch and see if it is in the parts book. Mopar generally used its own part numbers even for outsourced parts from Delco and other suppliers. Sometimes you might well find a Delco number on the actual part and a mopar part number on the parts box.

Dave
 
2022-01-19 Ignition Switch

2 mtg screws below column: 5/16 ss, ¼ R
1642641338380.png

Connectors: press down on tabs at top back of connector. Rock off of the ignition switch.
PXL_20220119_213431041 top.jpg

Translucent connector: red battery power wire, brown start wire, ignition run wire. Some corrosion at outer edge of battery wire terminal. I pushed a safety pin into the terminal and found 0 voltage drop from the battery to the connector terminal. Battery voltage: 12.55 V. Voltage at connector terminal: 12.55 V.
PXL_20220119_213948127 Batt & Start conn.jpg

PXL_20220119_234811997 Batt & Start Conn.jpg

Ignition switch: Delco insignia, 9 male spades, all in good condition. Copper looks good except for one looks like zinc. Part number on back 094 arrow. 2nd line: 3ND188
PXL_20220119_214356737 ign switch.jpg

from below
PXL_20220119_214436042.jpg

Part #
PXL_20220119_214532016.jpg
 
You probably have dirty contacts in the ignition switch. If you are trying to source an OEM unit, take the numbers off of your existing switch and see if it is in the parts book. Mopar generally used its own part numbers even for outsourced parts from Delco and other suppliers. Sometimes you might well find a Delco number on the actual part and a mopar part number on the parts box.

Dave
Hi Dave. I think you're right about the dirty internal contacts. Thanks, Ben
 
2022-01-19 Ignition Switch

2 mtg screws below column: 5/16 ss, ¼ R
View attachment 510345
Connectors: press down on tabs at top back of connector. Rock off of the ignition switch.
View attachment 510346
Translucent connector: red battery power wire, brown start wire, ignition run wire. Some corrosion at outer edge of battery wire terminal. I pushed a safety pin into the terminal and found 0 voltage drop from the battery to the connector terminal. Battery voltage: 12.55 V. Voltage at connector terminal: 12.55 V.
View attachment 510348
View attachment 510349
Ignition switch: Delco insignia, 9 male spades, all in good condition. Copper looks good except for one looks like zinc. Part number on back 094 arrow. 2nd line: 3ND188
View attachment 510350
from below
View attachment 510351
Part #
View attachment 510352

What I am seeing a semi melted plug housing on the yellow wire in, also the yellow, black and blue wires look like they are rubbed through to the copper wire. You check all that we talked about inside the engine compartment? Also, when you are troubleshooting try to make it fail then do it when the issue exists.? Make sure also that the splices are tight.
 
Now that you have your ignition switch off I would suggest attempting a cold start with a jumper wire in the translucent connector. If your problem persists you'll know the ignition switch is not the root cause of your cold start issue.
 
Hey just noticed the red wire terminal is significantly pushed back. I would change the connector if you can find one.
 
You could also hook up a multimeter on that ignition switch and check for continuity when you wiggle it.
Lots of possibilities to further diagnose the problem.
 
What I am seeing a semi melted plug housing on the yellow wire in, also the yellow, black and blue wires look like they are rubbed through to the copper wire. You check all that we talked about inside the engine compartment? Also, when you are troubleshooting try to make it fail then do it when the issue exists.? Make sure also that the splices are tight.
Hi Ray, I checked all the areas we talked about in the engine compartment. I did not find voltage drop at the bulkhead. I did find .3V drop across the brown start wires. Ignition switch volts in 12.45V, volts out at start wire 10.9V. Problem is in ignition switch or wiring/connectors very close to it.
Hey just noticed the red wire terminal is significantly pushed back. I would change the connector if you can find one.
Looked for a long time on ebay last night. Found Standard US-101 ignition switch for $27.14. Purchased. Cannot find connector
You have a wiring diagram for that?
Yes, from the FSM. Are you asking me to post it?
 
Now that you have your ignition switch off I would suggest attempting a cold start with a jumper wire in the translucent connector. If your problem persists you'll know the ignition switch is not the root cause of your cold start issue.
I purchased a new switch. Here 1/25 to 1/28.
You could also hook up a multimeter on that ignition switch and check for continuity when you wiggle it.
Lots of possibilities to further diagnose the problem.
That's a good idea. High 25°F tomorrow, but I can check indoors.
 
Time for a want ad for that connector someone might have a good used one.
 
You could also hook up a multimeter on that ignition switch and check for continuity when you wiggle it.
Lots of possibilities to further diagnose the problem.
Hi Theo. while my wife held the ignition switch on top of a towel on the kitchen table, I pushed the slotted actuator to the start position using a flat blade screwdriver. I had clipped one lead from the ohmmeter to the start wire terminal spade, which is at the lower right as you face the terminal side of the ignition switch. I pushed the tip of the red lead against the battery terminal spade which is in the middle row, far right side of the switch, as you face the terminal side of the switch.

I got a reading of 0.0 ohms. In other words there is no resistance in the switch when the key is at start position. I may have wasted my money ordering the spare switch on eBay last night. OTOH: it's nice to have a spare new switch and $27.14 is cheap.
Time for a want ad for that connector someone might have a good used one.
Hi Ray,
Based on the above, I agree that the wiring is the problem. I've got to do a starter on my 90 W150 tomorrow, big pain because I f'd up and used headers. I'll look again at the connector and wiring. If it can't be fixed, I'll put up a want ad Sunday. thanks! Ben
 
Hi Theo. while my wife held the ignition switch on top of a towel on the kitchen table, I pushed the slotted actuator to the start position using a flat blade screwdriver. I had clipped one lead from the ohmmeter to the start wire terminal spade, which is at the lower right as you face the terminal side of the ignition switch. I pushed the tip of the red lead against the battery terminal spade which is in the middle row, far right side of the switch, as you face the terminal side of the switch.

I got a reading of 0.0 ohms. In other words there is no resistance in the switch when the key is at start position. I may have wasted my money ordering the spare switch on eBay last night. OTOH: it's nice to have a spare new switch and $27.14 is cheap.

Hi Ray,
Based on the above, I agree that the wiring is the problem. I've got to do a starter on my 90 W150 tomorrow, big pain because I f'd up and used headers. I'll look again at the connector and wiring. If it can't be fixed, I'll put up a want ad Sunday. thanks! Ben
Another possibility. Note the slotted mount for the switch, if it was way out of adjustment, the start circuit might not have been engaging.

Dave
 
Another possibility. Note the slotted mount for the switch, if it was way out of adjustment, the start circuit might not have been engaging.

Dave
Good idea. Since this is mechanical issue, would it explain no start cold in Start/cranking position, but normal starting when engine warm Start/cranking position?
 
Good idea. Since this is mechanical issue, would it explain no start cold in Start/cranking position, but normal starting when engine warm Start/cranking position?

A warmed up engine is usually easier to start as the accumulated moisture has all been evaporated from the cylinders. Something has also heated up the plastic plug at some point to cause the melting. May have been a short of some kind that was repaired, but the damage was already done. If one or more contacts inside the switch was badly corroded, that can generate heat that might have cause a heating of the terminals back to the plug.

Dave
 
Battery is weak, it should be 12.8v dc or higher when properly charged;
running voltage should be 13.8-14.4 vdc While bench testing the switch assy is a good idea it's not under it's current load when trying to start the car so you won't see the problem. Switch should be replaced and the the bulkhead connector given a good look see and a remove and reseat.
 
A warmed up engine is usually easier to start as the accumulated moisture has all been evaporated from the cylinders. Something has also heated up the plastic plug at some point to cause the melting. May have been a short of some kind that was repaired, but the damage was already done. If one or more contacts inside the switch was badly corroded, that can generate heat that might have cause a heating of the terminals back to the plug.

Dave
New ignition switch is on order.
I agree that the damage is already done.
Connector is going to have to be repaired or replaced. Battery terminal, red wire, looks bad.
 
Battery is weak, it should be 12.8v dc or higher when properly charged;
running voltage should be 13.8-14.4 vdc While bench testing the switch assy is a good idea it's not under it's current load when trying to start the car so you won't see the problem. Switch should be replaced and the the bulkhead connector given a good look see and a remove and reseat.
When I was in tech school, they taught us that battery cold resting voltage should be 12.6. Right now, it's 12.57 volts. The battery cranks the engine easily.

Charging voltage is 14.10.

New switch is on order. I agree that the resistance test I did was not enough to determine whether the original ignition switch is bad because no resistance does not indicate how much current the circuit can handle. No resistance plus low amperage would still be a problem.

I have removed the bulkhead connectors, cleaned and oiled the spades, reinstalled. Condition is excellent, best I've seen.
 
New switch came today
Standard Ignition Parts US-101 NORS
Seller ad: fits 1970-1976 mopar tilt columns
Comparison: Original & US-101
Top
PXL_20220124_213928948.jpg

Gotta love it
PXL_20220124_213958152.jpg

Mounts
PXL_20220124_214058007.jpg

Spade pattern
PXL_20220124_214141457.jpg

Bottom
PXL_20220124_214234769.jpg

We have a match. Hope it's a match made in Mopar heaven.
Still working on the connector issue.
 
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