OK, so I finally got my '67 casting numbers/date code correct engine built and installed in my '67 RS/SS350. Thing has run pretty good for the last 200 or so miles. Last time I drove it was a trip of about 30 miles (home from work one Saturday).

It sat for 3-4 weeks. The when I went to start her last night, she wouldn't start. I have a Pertronix Flame Thrower/Flame Thrower II setup so I called Pertronix after some initial testing (checked for voltage at the coil+ with the key on).

They said to run pos from the battery to the coil and ground the distr housing and give that a try. I say I will, but I know this won't show me anything because I checked and had 12 volts at the coil + with the key on. Ran the jumpers and she fired right up! Removed the ground jumper, she continued to purr. Removed the pos jumper, she went dead immediately.

With the key in the "on" position she shows 12 volts from the + side of the coil to ground. When I crank her over the voltage drops to ~10 volts but she tries to start. As soon as I release the ignition switch back to the "run" position the voltage drops drastically and she goes dead. Once it dies the voltage returns to 12 volts.

I replaced the engine wiring harness when I installed the engine, taking time to replace the resistor wire in the process. The harness under the dash I believe to be original based on the sad shape of the RS diode I replaced at the ignition switch earlier. Could be the switch? I guess I'll have to trace the wiring back but I don't look forward to chasing wires under a very crowded dash.

Any suggestions as to the most reasonable approach to find the bad wiring/connection?

Thanks,

Dee

If the OE ign switch is being used, it may need taken apart and emery paper the contacts. I have done this to mine and worked successfully.

You might hook up a light or meter and check ign voltage under the sceneriao given to see the results given. The switch may not be going back to run position as the return spring may be weak.

Another culpruit could be wiring somewhere from the regulator buss bar to the ignition switch not making good contact to handle the current demanded, and after engine dies, current draw not needed, so voltage potential is shown, think of a water hose, open end verses nozzle off; lots of flow, but no pressure, closed nozzle, no flow but have pressure.

Thanks for the reply Everett#2390. I'm not looking forward to tracing wiring under the dash. I think I'll start at the horn relay and work towards the firewall to see if I can find anything there.

If not, I'll probably pull the ignition switch and trace back both sides to the firewall if the switch proves to be good.

Last time I got to the ign switch was to replace the RS headlight door diode. Had to pull the glove box, a bunch of A/C ducting, the radio, the A/C controls, the ash tray,and what seemed like a whole bunch of other stuff. I considered dropping the steering column and removing the instrument cluster. That would have really opened up the access, but it seemed to be too much trouble so I did not do that.

Well, wish me luck.

Dee

Last time I got to the ign switch was to replace the RS headlight door diode. Had to pull the glove box, a bunch of A/C ducting, the radio, the A/C controls, the ash tray,and what seemed like a whole bunch of other stuff. I considered dropping the steering column and removing the instrument cluster. That would have really opened up the access, but it seemed to be too much trouble so I did not do that.

Well, wish me luck.

Dee

If you can't just reach up to the switch, the cluster is a FAR cry easier than what you just described. I would've had a new switch installed thru the cluster before you got to the radio..........:yes:
Having the special nut driver is a big plus too, but it sounds like you have already experienced that.
Good Luck......:thumbsup:

MD88IROC,

Sounds like you speak from experience. You even make it sound easy. So much so, I'll probably give the column and cluster a try this time. I already know the other way is not so pretty. Plus, I should take a look at my Speed Warning system.

I don't have a special nut driver for the ignition switch. I think that's what you're referring to. If I remember correctly. I used a straightened paper clip.

By the way, what are you doing Saturday? I'm really a fun guy to be around, especially if we're working on my car!

Take care!

Wow, Everett#2390, 13,000 posts!!!!!!!!!

I'm humbled.

MD88IROC,

Sounds like you speak from experience. You even make it sound easy. So much so, I'll probably give the column and cluster a try this time. I already know the other way is not so pretty. Plus, I should take a look at my Speed Warning system.

I don't have a special nut driver for the ignition switch. I think that's what you're referring to. If I remember correctly. I used a straightened paper clip.

By the way, what are you doing Saturday? I'm really a fun guy to be around, especially if we're working on my car!

Take care!

Dang !!! I'd love to run down to OK, but it's my wife's birthday weekend and we are going even farther north...:yes:

Seriously, the cluster comes out pretty easy and yes, I've had mine out 6 times now. :(

Rats, just my luck. I was looking forward to taking her out for a cruise down Rt. 66 after we got her running. I only live a mile from Rt. 66. Cruise there often.

I'll dig out my service manual for step-by-step instructions and maybe get started this weekend.

Thanks for the input! And have a great weekend.

Dee

You might squirt in some WD40 to lube the tumbler external threads.
Next time there is no voltage, jumper in a hot wire and see the results - anything to prevent going behind the dash.

Hmm, I haven't had too much of a problem pulling out the ign switch.
Remove one battery cable,
Unscrew the tumbler with key and paper clip,
Remove the bezel nut,
Reach up from the bottom of the dash and grab the switch body,
Gently pull down, harness does give alittle,
Unplug switch.

I just seen the count...wow!

Given your encouragement I decided to give it a try. I removed the ignition switch from the dash but the wiring did not have enough slack to get anywhere near the bottom of the dash. The AC duct and numerous wires/cables just would not allow it.

So I dropped the steering column and removed the instrument cluster as described on the service manual. Did not take long ans was not difficult (thanks MD88IROC). Changed out the switch but she still would not start.

Wiggled the engine wiring harness and the wire at the coil and she fired up! Ran for a short time then killed her and she would not restart. At least now it looks like the issue is under the hood, not the dash. I'll continue to look tomorrow.

Not a total loss though. While I had the instrument cluster out I was able to repair a bad connection at the diode for the headlight doors. Once again they work better than new!

Dee

Too bad the switch didn't cure it, but it looks like you're headed in the right direction. Congrats on conquering the instrument panel...:thumbsup:

Finally found the problem. My old engine harness was apparently the original so I replaced it when I replaced the engine. I now have a Pertonix so I cut out the resistor wire and soldered in a standard wire. The problem was the soldered connection. It had broken free enough to make an intermittent connection.

I only found this by wiggling the wiring harness while the car was running. I did this at night, fortunately. I thought the problem might be at the distributor's wire terminal. I just happened to see the spark through the wire cover (tape?). Sometimes it's better to be lucky than good!

If I had only worked on this during the day it may have taken forever (if then) to find this.

Happy motoring!!!

Dee

Finally found the problem. My old engine harness was apparently the original so I replaced it when I replaced the engine. I now have a Pertonix so I cut out the resistor wire and soldered in a standard wire. The problem was the soldered connection. It had broken free enough to make an intermittent connection.

I only found this by wiggling the wiring harness while the car was running. I did this at night, fortunately. I thought the problem might be at the distributor's wire terminal. I just happened to see the spark through the wire cover (tape?). Sometimes it's better to be lucky than good!

If I had only worked on this during the day it may have taken forever (if then) to find this.

Happy motoring!!!

Dee

It's always a good feeling when you KNOW you've finally found the little bugger and have it repaired properly....:hurray:
Congrats.....

Congrats on the find. How do you like your Pertronix? I run the Plug N Play unit and I think it's great. By the way, did you know that the Flame Thrower 2 coil allows you to open up your plug gap to around .050"-.055" for better combustion?

I like my Pertronix okay. I'm running the flame Thrower II. I think I gapped my plugs at ~0.045". Can't recall for sure.

I was going for the stock look and didn't really have a god stock distributor to convert so I sprang for the Pert distr.

You could have a ignition switch problem, or the problem could lie elsewhere in the power circuit. What you are seeing is an indication of a bad connection - 12 volts under no load and nearly nothing when loaded.

Use the voltage drop test with a digital volt meter (or analog) to find the bad connection. This will allow you to isolate large portions of the circuit without having to stand on your head - at least until you narrow the problem down a bit. You might substitute a test lamp for the coil temporarily to load the circuit down while you test.

Start big - measure from the battery (+) to the coil (+). You probably will see quite a few volts there based on what you're telling us. Normally you'd see nearly zero volts up to a few hundreths of a volt.

The trick is to move your meter probes from point to point until you find the specific branch in the circuit where your voltage drop is. Measure battery (+) to the IGN fuse. Check each end of the fuse including the fuse tab and fuse end separately (a common bad connection point). Check the horn relay buss bar to IGN fuse. Check the IGN fuse to coil (+). Eventually you'll be testing the power wire to the ignition switch to the IGN fuse and battery + to the ignition switch.

In all cases, a near 0 volt reading is ideal. When you see more than 0.1 volts or so, you're revealing a bad connection somwhere between your probes.

Just to give you an idea of what can go wrong. When using HEI or other electronic ignition setups, you have to replace the resistance wire from the firewall bulkhead connector to the coil with a copper wire. I've seen guys try to spread open the old brass terminal and crimp / solder on a new copper wire. It doesn't take long for corrosion to develope and create a bad connection at the terminal crimp. The voltage drop method will isolate that problem fairly quickly.