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Discussion Starter #1
1969 Convertible. Since I rebuilt the engine, it started to not want to start once the engine warmed up. The GEN light comes on in the ON position and there is a distinct click when turning to START and a similar click when I let the let return to ON. I thought it was a hot starter, so I changed the starter. Still did it.

I did pull the column when the engine was out to clean it up and rebuilt the joint in the shaft. When I put it all back together, I got the ignition switch a tad too far down the column an I had to really stab the key to get it to start. I moved the ignition switch just a bit and it worked fine.

Wen the car does not start, I can jump the ignition terminal on the starter to the batter and the starter spins just fine. That tells me that there is a problem with the purple ignition wire, or the ignition switch.

When this happens, my hood tach needle sticks at 4k rpm.

Could this be a bad ignition switch? It does not seem logical that it would take this moment to go bad, but I guess what reason does a part need?

1. Does it make sense that a bad ignition switch will intermittently not start the car?
2. Does it make sense that a bad ignition switch could send some weird voltage to the tach and cause it to act stupid?

Thanks,
Mike
 

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jump the 2 purps at the bottm of the column

does it turn over if they are jumped ??

thats your nuetral safety switch

ST
 

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jump the 2 purps at the bottm of the column

does it turn over if they are jumped ??

thats your nuetral safety switch

ST
x2. When it does not start, (assuming automatic?) try putting the car in neutral. Cars with automatics will start in either P (Park) or N (Neutral). My '73 Fury does this on me and I know the neutral safety switch is OK, but my steering column selector indicator/linkage is a bit sloppy, so I just have to jiggle it sometimes to fire up.

However, the tach needle may indicate something else, as in it is getting some bleed over voltage or grounding. The ignition switch has a series of contact points inside and it is possible the switch is worn out and allowing for contact within the switch housing that is not meant to happen - they do wear out. The tach operates off the coil, which operates off the key switch. Or, you could have bare wire, short, or pinched wire.

Assuming it was OK before the engine removal/rebuild, I would first check all my wiring and connections. Did you make sure all grounds were reinstalled? Engine to frame? Firewall to engine? etc..

It has been brought up that the purple wire at the starter solenoid can look good on the outside casing, but actually have corrosion internally going up into the wire a small amount - enough to cause enough resistance to create key/start problems. You can splice in a new section to replace any corrosion that may have built up in the wire end.
 

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Discussion Starter #4
Thanks both. Car was born automatic, previous owner installed Tremec 5 speed. Pretty sure my neutral safety switch is no longer connected. Problems started after engine build and replacement of steering column. Already tried to adjust the ignition switch but it seems to only have gotten worse. I could try a jumper wire from switch to starter but was hoping for a sign it was one or the other (wire or switch) since I guess I need to pull the column to do either. Car has AC and there is not a lot of room. Would you think I need to pull column?

Thanks again
 

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Discussion Starter #5
And yes, about the grounds. I even added the original straps since they were not present when I bought the car. I will check the crimp on the ignition wire at the starter but all that looked good......
 

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I've had 9 GTO's and have worked on a LOT more. In almost every single case, the culprit (with these exact same symptoms) was the purple S wire from the switch to the solenoid. Replace that wire and you should be good to go. I've had one bad solenoid (diagnosed when it wouldn't crank with a jumper switch installed) but have never had a bad switch. 99% chance it's your purple S wire.
 
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