1957 Pontiac ignition wiring
 

Hi All,

I have re-run the wiring harness in my 57 Super Chief and I'm having issues with trying to get the motor to start. I'm worried that have wired things wrong. I have a few questions:

1. Does a 57 Pontiac have a starter relay (doesn't look like there's one)?

2. What wires should be connected to the positive terminal of the starter solenoid (other than the batter cable)? Colors or drawing would help

3. Should there be a wire running from the ignition coil to distributor? (not referring to the spark wire). Note: I upgraded to Pertronix ignition module in the distributor.

Some of these questions may sound silly, but I'm a novice when it comes to wiring and I'm having to re-wire with the original harness from scratch. And the shop manual diagram is difficult to follow. Thanks for your help.

Dave

The battery cable connects to the big post on the starter. (at least later models, don't have a 57 manual with me)
Some have a horn relay but don't think battery cable goes to it first?

Anyway, there should be a wire that goes from the switch when in cranking position to a smaller post on starter. If more than 1 small posts, need more info.

When power applied to the small post from ignition switch (just thought it might have a floor mounted switch to crank, maybe?)

That small wire activates the starter relay which makes it crank.

The distributor should have the negative post wire from coil connected to it.
The + side of coil should have 2 wires probably from ignition switch so when on or in cranking position applies power to coil.


If engine cranks but does not fire/start let us know.


:confused:

@johntal Thank you very much. Any chance you might have drawing or schematic?

Thanks to Larry Gorden the original 1957 Pontiac wiring diagram can be found here:
https://www.pontiacsafari.com/57/Sho...nstruments.pdf

I know very little about the Pertronics unit, but if it all fits inside the distributor you'll need to bypass the stock "coil resistor" (that's what it is called in the Pontiac wiring diagram, sometimes known as a ballast resistor) so the coil primary terminal (+) has a full 12 volts when in crank and run.

@BillHanlon. Thank you for the link. Yes, the Pertronix unit fits inside the distributor. Thank you for letting me know to bypass the resistor. I still have it connected.

So according to the diagram on page 12-28 it looks like there is wire going from the coil to the distributor. Right now I don't have a wire running from the coil to distributor.

You need that wire!
The distributor should have a wire hanging down from it?

Does the engine crank over?


:confused:

No, the engine does not crank over.

The other question is about the wires to starter motor. I have a large yellow wire and a thinner purple wire connected to the starter. Are they supposed to be on the same terminal? Is one supposed to be on the battery terminal.

In the column of text at the right side of the wiring diagram I posted you will find an entry for "Starter". It says there should be a yellow wire from the battery and a purple wire attached to the starter solenoid.

The big yellow wire connects to the large stud on the solenoid.

The purple wire attaches to the small stud on the solenoid. If there are two small studs (like shown in my attached picture) connect the purple wire to the stud marked "S".

Great. I will have to recheck how many terminals are on my starter.

I can't see a wire hanging from my distributor. I'm assuming it may have been removed by the previous owner when he swapped in the Pertronix module while the engine was out of the car. I'm guessing I have to attach a new wire to the distributor somewhere in the housing.

The pertronix should have a wire that comes out of the distributor?
If not, something may be wrong with it?


Taking cap off should show something I guess.


:confused:

Hey Guys,

The yellow and purple wires from the starter go into some sort of connector that an extra red wire running out the other side. Any idea what this is? A junction of some sort? See attachment.

That yellow wire isn't near big enough to be the wire attached to the big lug on the solenoid. The yellow wire mentioned in the wiring diagram I attached above would go directly from the battery's positive post to the big lug on the starter's solenoid.

When you say you "have re-run the wiring harness in my 57 Super Chief" do you mean you are just reconnecting existing wiring or are you replacing existing wiring? Are you working with what you think is original wiring or is it a generic after-market harness?

I have three terminals on my starter. One large, one medium, one small. I know the small one "s" is for the purple wire. I assume the largest one is for the battery cable. Should yellow wire connect with battery cable on the same terminal or use the medium terminal?

@Billhanlon I'm working with the original wiring harness. It was removed when I got the car and so I have re-run it. I've got the ignition switch connected (it's a multi-pronged plug) and have traced most the wires. The pink wire is messing me up a bit. According to the diagram, I think the pink wire from the ignition switch is supposed to connect to the junction (in my pic) but it's connecting to the transmission switch thing on steering column.

Looked in the wiring diagram and found the terminal block that you posted a picture of.

So it looks like the battery cable and yellow cable should be on the same terminal. is that right? It also looks like there is a ground wire on the "S" terminal as well.

Assuming an automatic transmission (which the wiring diagram doesn't) the pink wire going from the ignition switch "sol" to the "transmission switch thing" should continue from another terminal on the "transmission switch thing" through the junction previously discussed to the "S" terminal on the starter solenoid. The "transmission switch thing" is what only allows starting the motor while the transmission is in Park or Neutral.

Correct. The yellow goes into the trans switch, while the purple wire goes out to the "s" terminal of the starter. So looks like that is good. yes, it's an auto trans. Now I need to know if the yellow wire connects to the same terminal as the battery cable.

Yes, the large terminal on the solenoid.



No ground on the "S" TERMINAL. If you are talking about the ground shown on the left side of the solenoid, that is frame ground for the solenoid. Basically just metal on metal from the solenoid case to the starter case.

@Billhanlon. I really appreciate your help and all the answers you're providing. I've tested the yellow wire for power, and there is power running through the junction connector and there is power at the Ammeter. The batter is connected, I turn the key and still no go. What should I check next?

I think I may have figured something out. I'm using Pertronix module in my distributor and a Pertronix coil. Therefore, I don't need to run the black and purple wires through the resistor. So I'm wondering if I connect both the purple (ignition #1) and the black wire (ignition #2) to the positive terminal of the coil.

The coil connections won't keep the engine from cranking.

Make sure the transmission is in park.
Use a screwdriver to jump between the big post on the starter and the S post on the starter for a second.
Engine should crank.
What happens?

By the way, do you have a multimeter? If so, analog or digital?

Sun is setting here in Toronto, so I will give the jump suggestion a go tomorrow. I have digital multimeter. I will give you an update once I give the jump a try. If it doesn't crank like you mention, what could be the issue (just being proactive)

Dead battery
Battery cables not connected at battery
Battery + cable not connected to solenoid
Battery - cable not connected to engine block
Solenoid not "pulling in" (no "thunk")
Solenoid contactor bad ("thunk" but no crank)
Starter defective ("thunk" but no crank)

Should have added "Make sure the ignition key is off." at the start of the list above.

@Billhanlon

Thanks. How do I know if the car is in park. I have the trans linkage connected at lower column but I haven't assembled the steering wheel parts yet.

Remove the fat wire from the coil to the distributor instead. I just want to eliminate any chance of starting the engine while this test is going on.

@Billhanlon. It worked! I touched the screwdriver to the "S" terminal and main terminal of the starter and the motor cranked without issue. No "thunking". So I know the starter is working. Now to figure out where the issue lies in the ignition system.

I've traced all wires and all them except for are connected properly. The pink wire from the ignition switch (Sol) is connected to the transmission linkage on the steering column. But the wiring schematic shows it going to junction block just before the starter. Should I run the pink wire from the SOL on the ignition switch to the junction?

Also, I have confirmed that I have power at the ignition switch through the thicker yellow wire. I'm guessing I've done something wrong with the ignition 1 and 2 wiring.

I won't be home until dark in Toronto and don't have switch. copy of the wiring diagram with me. And the weekend is pretty busy for me.

Try jumping the hot all the time wire to the SOL wire at the ignition switch with the key off. Should rank and may try to start, so leave the coil wire undone as in the previous test.

I may some time for phone support tonight between 6 and 10 CST if you'd like. I'll send a private message with my phone number.

Can't figure out PM.

My phone is 713-468-6417

Hi Bill,

I would be great if I could call at 6pm CST. I look forward to speaking with you.

Dave

6 is great. Just got home.

Dave: When you have some free time you should read the first five pages of this https://www.pontiacsafari.com/Hydram...structions.pdf

It is from a 1956 manual, but your '55 tranny is the same.

I'm glad we figured out your immediate problem, but am too embarrassed to admit it took us this long.

Bill, he has a 57, that is link to the 56 slant pan. Good job on helping him out! Here is link to the 57 hydramatic manual.

https://www.pontiacsafari.com/Hydramatic/1957/index.htm

Dave, open section 1 and read that -- when you have some free time and need entertainment.;)

Larry:

Dave's (locked up) 347/ and unknown quality Strato-Flight have been replaced with a 55 287 and a slant pan Hydra-Matic. Could be fun getting the throttle linkage right.

By the way, the wiring diagram in the 57 Shop Manual on your site does not show the switch that prevents starting the engine except when in park or neutral with an automatic trans. And that is where Dave's problem was.

Ah, somehow, I missed that. I suppose the Neutralizer Switch isn't shown in the wiring diagram because Hydramatic was an option. Now I'm wondering if Dave has the correct gear selection indicator for the slant pan (no "P"). And does he have the correct Neutralizer Switch for the slant pan. Per the MPC Group 4.054, it is different than the 57 switch. The transmission manual tells how to adjust it. But I haven't found a wiring diagram for it anywhere.

As I think about this, I'm wondering about the internals and levers of the steering column, are they the same for 57 and 55 slant pan. I doubt it.

Dave didn't say until we were on the phone.

Given that the "start" position is all the way CCW on both shift levers, this shouldn't be too hard to deal with. And reverse is all the way CW. I'm more concerned about the slant pan's complicated and very sensitive throttle to tranny linkage.

I wanted Dave to read about the "start in neutral, park in reverse" operation of the Dual Range HM.

Bill, Pontiac Pat has done the conversion of Stratoflight to dual-range on a 56 Star Chief. This would be similar to installing a 55 dual-range in a 57. I'll email Pat with CC to you and ask about any gotchas.

I found a 57 Pontiac wiring diagram on www.oldcarmanualproject.com, attached. It is different than the Shop Manual wiring diagram and shows the Neutralizer switch, including connection to backup lights. This diagram might be a little easier to read.

So Dave's (and other automatic transmission cars) would be missing that little jumper marked "Synchro-Mesh cars only".

That's the way it appears. However, per the Shop Manual Section 14 (Accessories), there are two different backup switches, one for Hydramatic and another for Standard Trans. That's validated in the MPC, Group 2.698, different switch depending on Hydramatic or not. The back-up light switch for Hydramatic is also listed in Group 4.054 as SWITCH ASSY., TRANS. AND BACK UP LAMP.

Makes sense to me. The the standard transmission (where reverse is CCW on the lever) backup light switch would have to be different than the automatic (where reverse is CW on the lever).