[Billy]

70SS454 only starts when it is cold. Always on the first turn. When it warms up it acts like the ignition switch is dead sometimes and then sometimes the starter drive will engage, starter will spin, engine will make less than 1/2 revolution and the starter drive disengages (starter motor still spinning). Sometimes after you have hit the key 5 or 6 times(when the starter drive is doing its disengaging thing)the key switch will just go dead. If you let the motor cool off it starts on the 1st revolution every time. This is driving me nuts!!!

Did several searches and have run out of clues.

I have replaced the solonoid 3 times,the starter drive most recently, and shimmed the starter numerous times. The teeth on the flexplate look good all the way around. Timing is set at 14 deg with 11-1 compression.

One thing curious. I have a remote start button so I can kick the engine over when I am working on it. This button is wired direct from the battery to the starter. When the engine is hot and the starter is acting crazy it will start perfectly every time if I use the remote start button. After you start it with the remote the key switch will then work perfectly for 2 or 3 starts and then go's dead again. Even then the remote switch will always start it on the first spin.

I eliminated the neutral safety switch as a possibility by wiring around it (for now).

Keyswitch is supplying 12 volts to the HEI when the starter is acting up. Could this possibly be a problem in the ignition switch mounted on the steering column?

Any advice would be appreciated.

Billy

Billy

 

[Jim Streib]

Since the engine cranks fine hot or cold with the remote starter button then I would think the starter is fine.
I wonder if it's a bad connection somewhere in the factory wiring or like you said the ignition switch itself.
The starter solenoid wire coming off of the "S" terminal on the starter should go up and over the engine to the bulkhead connector by the brake booster. I've seen this connection when taken apart be full of some type of black tar material.
I would maybe try some different spots with a meter to check the voltages on the starter solenoid wire starting at the solenoid itself and then going to the bulkhead connector and then up to the ignition switch. Where ever the voltage is dropping that is the area that needs to be fixed.
Maybe too once the engine is warm that some wires are moving around and not making a good connection.
Jim

 

[Billy]

Jim that's a good idea about the bulkhead connection. I will have to get the car hot and see if my wife will hold the key in the start position while I take some meter readings.

I have also ruled out the starter and solonoid as the car always starts via the remote start switch. Yesterday I moved the remote inside under the dash. It was getting more than a little embarrising to have to open the hood to start the car.

One other possibility I thought of last night might be the difference in wire size. When I origionally installed the motor I noticed the purple wire going to the S terminal did not look like it was in good shape so I replaced it with some 12 or 14 Ga. wire. I spliced in just forward of the bulkhead at the point the purple wire comes out of the wire bundle at the firewall. The remote switch is wired with 10 Ga.

I will try to get some meter readings this evening if I can invoke my wife's help. She likes to help me with the car when she can but say's that she has to keep the family running while I keep the Chevelle running. Fortunatly for me she does a great job at both. Guess I owe her a beer!

I will post again after I take some readings with the meter.

Billy

 

[John_Muha]

Try measuring voltage from your NSS jumper to ground as you crank the car. Easier than crawling under it and measuring the "S" terminal. Suspect the voltage is too low to engage the solenoid. Measuring the HEI input is the wrong place.
Bad ignition switch.

 

[Billy]

John that's a great idea. Especially since I have the top plate removed from the console and the NSS jumper is easy to get to. Wish I had thought of that before

.

Your comments about not having enough voltage to engage the solonoid are probably on the mark. Early on the problem was much worse. I knew that I had a weak battery and found after changing it out that the problem took longer to surface with a good "hot" battery. When the old "weak" battery was used the key switch would go dead sometimes even when the engine was cold. After the battery change was when the starter drive would prematuraly disengage. After several attempts to start the key would then go dead. Probably because some of the voltage had been drained off. That would also probably explain why after starting with the remote switch and letting the engine run for a few seconds, you could turn it off and restart it with the key 2 or 3 times before the problem would resurface. Being as the alternator was putting a little charge into the battery.

In my mind everything is now pointing to the ignition switch. Guess I will know after I take some measurments.

Thanks,
Billy

 

[John_Muha]

While you are digging around in there also try this. Measure fuse block BAT (battery) terminal to ground as you crank the key. This should remain at 12 volts if the starter is not engaging. This point is also the input to the ignition switch.
Next connect meter positive (+) to the BAT terminal on the fuseblock. Connect meter negative (-) to the NSS jumper. When you crank the car expect to see less than 1 volt DC on the meter. The voltage you are reading is the lost voltage across the switch contacts.
Example:
If BAT is 12 volts and you read 2 volts on the meter, that means only 10 volts are coming out on the NSS jumper. The ignition switch contacts are dirty enough to lose 2 volts. (This assumes the ignition switch connector is OK, but guessing it is).