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Discussion Starter #1
Hey Guys, Thanks in advance for any Help you can Offer. All suggestions are welcome. I have a 68. Its had a few things done to it along the way. When I try to start the car today it blows the Main fuse Instantly. I installed a fuse in place of the Fusable Link a while back. The Ignition switch is NEW as I have tried replacing it to fix this in the past. It worked for a while but today it is NOT. I have had this issue on and off for a LONG time now. Today I disconnected the igniter wire going to the starter, but it made no difference and the fuse blew again when I tried to turn the key to the start position. Seems like its a dead short and I have looked at the wires in the dash a few times But I have never seen anything that looked to be problematic. My assumption based on how its acting is that I have a dead short in the wire from the Ignition switch to the starter itself??? I am confused. I am going to tare into all this again next day I have off BUT I am looking for some Ideas. Please help me out. Any way I could narrow down the search would be GREAT!!! at the least it seems like the problem is after the Ignition switch I guess

AGAIN - thanks for any help.
Arkangel77
 

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Is the newer fuse the same capacity as the old fusible link?
 

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Discussion Starter #3
That i am not sure about. I can tell you that it blows anything from 20-50 amp fuses instantly. Before this last flair up. It would start run and do anything required with a 20amp fuse in there. When I say it blows, the instant you engage the starter portion of the ignition switch it pops loudly enough fir you to here inside the car. I guess as soon as the switch sends voltage to the starter it blows the fuse.
 

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Are you talking the fusible link on the main power feed to the firewall connector, or the fusible link on the charge wire from the horn relay bus bar to the battery? If the former, and if all electrical accessories work correctly and the fuse does NOT blow when your ignition switch is turned on, but then DOES blow when you turn it all the way to start (and if the fuse is the right size), clearly the cause is excessive drain through the ignition switch in the start position. That would be from the wire from the ignition switch to the starter. Places it could be shorted include the starter (you already removed this I think), the wire run from the firewall connector across the firewall to the starter (chafed wire?), the firewall passthrough (damaged? or perhaps just no dielectric grease and arcing somehow? not sure if the latter is possible based on contact position), underdash (chafed wire?), or within the ignition switch itself (arced and the start position contact is shorted to ground?). I guess you could have the resistor bypass wire to the coil shorted somehow but I'm not certain that would do it.

I think my approach would be to, with the car turned off, pull apart the firewall connector and take an ohmeter to check for resistance between a good ground and the engine side then the dash side of the ignition wire in the firewall connector. Should be infinite; whichever side is low/no resistance is where your problem is. Could also then pull the plug for the ignition switch off and repeat it with the contact in the plug and the contact in the switch. Should at least narrow down which segment is shorted.
 

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I just realized another possibility - if you have a neutral safety switch, I think the current from the ignition switch to the starter solenoid runs through it. If there's a short there, it would do it. I don't have one so I'm not certain of the anatomy of the connection, however.
 

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Cory,
Sounds like you have an intermittent short as you claim to have had this problem for a while. I agree with Brian on the neutral safety switch...to eliminate it, remove the pink/purple wire from the starter solenoid and isolate. Try the ignition switch again to see if the fuse blows or if you have an ohmmeter, connect one lead to the pink/purple wire and the other to ground...is there continuity? If so, the neutral switch is shorted out. If the fuse doesn't blow or there is no short in the PPL wire, then, move on to the starter solenoid to check for a short.
 

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OK Cory, Do you have a wiring diagram of the 68 Camaro? If no, don't fool around get one! Look at the diagram and find all the fusible links. Write down the location of all of them. Trace the white/yellow/purple wire from the connector on the firewall to the + side of the ignition coil. There is also a yellow wire in that connector that runs to the "I" side of the solenoid. The wire on the - side of the coil goes to the distributor. The purple wire from the neutral safety switch connect to the "S" side of solenoid. The wires on the back of the ignition switch are 12 Purple- connects to the neutral safety switch and then connects to the S side of the solenoid. 12 Pink- Ignition power supplies power to gauges, signals, back-up circuits and ignition circuits. 12 Brown + 24 brown/white- supplies power to wipers, heater, AC, radio circuits. 12 Red- main power input horn relay via firewall connector. 20 Dark Green associated with temperature gauge and sensor. 20 Black- Door jamb switch used for key in the ignition buzzer. 20 Pink- To horn relay key in the ignition buzzer connection via the firewall connector. Check all these wires to see if grounded anywhere. Check all connections on the horn relay from the wiring diagram. If anything has been added to the wiring let me know. What size fuse did you install in place of the fusible link? Fusible links are made for replacements not fuses. Check at Advance Auto I have seen them there.
 

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Discussion Starter #8
Awesome replies guys - So much info. I needed to read them several times to process =). I will try to reply to most of the questions I was asked.

The fusable link I replaced is the one located driver side front next/near the Horn relay ( i believe ).

When I turn the ignition on all accessories work Wiper, radio, lights, horn, and so forth. The Fuse blows when I try to start the car.

I have had this on/off again problem for a while now!

The neutral safety switch is a great Idea that I have not considered previously. Its not the stock switch. It has an aftermarket performance shifter and I *THINK* the safety switch is on the shifter. I will look into that for sure!

I do not have a wiring diagram. However- I will go threw the process that "Doug" has spelled out and that sounds like It should definitely lead me to the short (i hope).

Having replied to all that - I think the Neutral safety switch is 1st on my list of things to look at and eliminate.

GREAT replies guys - I find great value in talking problems out with others and getting ideas. 2 heads or 200 are always better than one =). I will reply when I figure something out or if I get stuck again. Thank you all very Much
 

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Have you had the trans out since this started? There might be a pinched wire in the harness on the way to the starter. It sounds like the only place in the circuit this problem could be is in the Purple wire from the switch thru the NSS to the starter or the yellow bypass wire from the starter to the coil.

Jeff
 

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Discussion Starter #10
Have you had the trans out since this started? There might be a pinched wire in the harness on the way to the starter. It sounds like the only place in the circuit this problem could be is in the Purple wire from the switch thru the NSS to the starter or the yellow bypass wire from the starter to the coil.

Jeff
Yes the Trans was Just rebuilt - However, there is Only 1 wire going to the starter and it was not pinched - No wires were pinched threw the transmission work. But thanks for the Idea
 

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Discussion Starter #12
Very Good! thanks bunches =)
 

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Cory,

The circuit is pretty straight forward. From starter in -> Solenoid, through firewall, nuetral SS, cold side of ignition switch.

I assume this only happens when cranking? If it short when you have it the run position then it could be a bunch of different things.

Unhook the NSS and see what happens. If it still shorts while cranking then it's the ignition switch back into the car. Here's a sure fire way to rule in/out the ignition switch. Remove it from the dash. This will remove the ground if the inside is shorting out.

If you have meter it makes this a lot easier.
 

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Discussion Starter #14
I do have a meter. I plan to check the NSS probably tomorrow. Thanks great replies
 

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Also there is a wire that runs from the starter solenoid to the coil that only gets power while cranking. It supplies a full 12v to the coil while cranking as opposed to the lesser amount supplied via the resistor wire in the run position. Check that wire for a short too. If you have an aftermarket electronic ignition or HEI you might not have that wire or it may just be laying around unused at the back of the motor causing your intermittent problem.
 

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Discussion Starter #16
Also there is a wire that runs from the starter solenoid to the coil that only gets power while cranking. It supplies a full 12v to the coil while cranking as opposed to the lesser amount supplied via the resistor wire in the run position. Check that wire for a short too. If you have an aftermarket electronic ignition or HEI you might not have that wire or it may just be laying around unused at the back of the motor causing your intermittent problem.
It dose have a HEI distributor and there is only 1 wire going to the starter. there are a few Unused wires that I have taped and loomed out of the way against the fire wall. The car came with a lot of these modifications done and its bin challenging to figure out the previous owners work. ALSO - it ONLY dose this when I try to start it. when the ignition is just sitting in the On/Run position its fine.

Thanks guys
 

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u have a short in the big purple wire somewhere between the switch and isolating switch and there and the starter....could also be the terminal on the starter if at some piont the nut over torqued.
Cause, loose connections or another common issue here is at some piont the wire has been shorted during a starter install... or loop pinched as suggested above.

1/ check continuity between it and ground with battery disconnected at each connection in the circuit
2/ To do quick check.. disconect the purple wire at each connection, then see if blows
or
2/ disconnect purple wire and run a long temp wire from under dash , out the door, to starter.
 

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Discussion Starter #18
u have a short in the big purple wire somewhere between the switch and isolating switch and there and the starter....could also be the terminal on the starter if at some piont the nut over torqued.
Cause, loose connections or another common issue here is at some piont the wire has been shorted during a starter install... or loop pinched as suggested above.

1/ check continuity between it and ground with battery disconnected at each connection in the circuit
2/ To do quick check.. disconect the purple wire at each connection, then see if blows
or
2/ disconnect purple wire and run a long temp wire from under dash , out the door, to starter.
Yes I understand - that is exactly what I plan to do. My folks came over for a surprise visit today and now its time to get ready for work. Looks like I wont get to work on it till the 1st of next week. I will let you guys know what I find. Thanks, Arkangel77
 

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Discussion Starter #19
OK guys - I got to work on it today FINALLY. It was in fact the Neutral Safety switch. The housing had cracked and a hold down bracket was grounding to the Internals. Here are some pics. :D





 

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Discussion Starter #20
New Parts are Ordered - Thanks for the help guys
 
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