Starting wierdness
Thread Starter
Pro
Joined: Jan 2007
Posts: 524
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From: Auckland New Zealand
Starting wierdness
On starting the car either from hot or cold the engine does not fire until I release the key back to ignition and then just catches and runs fine. I can sit there and crank the engine for ages and it does not remotely sound as if it is going to fire.
It's as if there is no current getting to coil when engine is cranking.
Some one may have come across this starting issue before so I figure I will ask the knowledge base here before going and bothering the auto electrician.
It's obvious that the car has been "got at" by previous owners, particularly in the electrical area - odd connectors, a few wires going nowhere in engine bay etc.
I have just got my hands on this car after having to wait 2 1/2 months for it to be shipped halfway round the world and it's finally sitting in my garage.
I have to go down and pinch myself just to make sure it's real!!!
Neville
It's as if there is no current getting to coil when engine is cranking.
Some one may have come across this starting issue before so I figure I will ask the knowledge base here before going and bothering the auto electrician.
It's obvious that the car has been "got at" by previous owners, particularly in the electrical area - odd connectors, a few wires going nowhere in engine bay etc.
I have just got my hands on this car after having to wait 2 1/2 months for it to be shipped halfway round the world and it's finally sitting in my garage.
I have to go down and pinch myself just to make sure it's real!!!
Neville
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
The pink wire from the R terminal on the starter solenoid is not connected to the + primary ignition coil lug. (lackacontinuity)
Last edited by magicv8; Jun 22, 2007 at 08:49 PM.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
"It's as if there is no current getting to coil when engine is cranking."
I think you've found the reason for it not starting. All you have to do now is find the cause. I'd guess it's somewhere between the solenoid and the circuit back up to your coil when the ignition circuit is in the starter bypass mode. It's easy to check that wire with a test light. If it's dead at he solenoid, take it apart and clean the contacts. But, who knows, somebody could have eliminated that circuit.
I think you've found the reason for it not starting. All you have to do now is find the cause. I'd guess it's somewhere between the solenoid and the circuit back up to your coil when the ignition circuit is in the starter bypass mode. It's easy to check that wire with a test light. If it's dead at he solenoid, take it apart and clean the contacts. But, who knows, somebody could have eliminated that circuit.
Race Director
Joined: Nov 2000
Posts: 10,343
Likes: 668
From: Beverly Hills (Pine Ridge) Florida
As the guys above have indicated, you are missing electrical juice when the starting circuit is engaged. The starter solenoid has a separate contact for supplying the ignition coil when starting. This circuit bypasses the ballast resistor, so that full battery voltage is supplied to the ignition coil. The failure you are seeing indicates (as stated above) that the circuit is either malfunctioning, or not there to begin with.
Recommend getting a shop manual (which will have a schematic) for your Vette.
Good luck,
Plasticman
Recommend getting a shop manual (which will have a schematic) for your Vette.
Good luck,
Plasticman
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
There are links to 66 wiring diagrams at the bottom of this web page:
http://www.corvetteforum.net/classic...e/index5.shtml
http://www.corvetteforum.net/classic...e/index5.shtml
Thread Starter
Pro
Joined: Jan 2007
Posts: 524
Likes: 12
From: Auckland New Zealand
As the guys above have indicated, you are missing electrical juice when the starting circuit is engaged. The starter solenoid has a separate contact for supplying the ignition coil when starting. This circuit bypasses the ballast resistor, so that full battery voltage is supplied to the ignition coil. The failure you are seeing indicates (as stated above) that the circuit is either malfunctioning, or not there to begin with.
Recommend getting a shop manual (which will have a schematic) for your Vette.
Good luck,
Plasticman
Recommend getting a shop manual (which will have a schematic) for your Vette.
Good luck,
Plasticman
It's a bit late at night for my brain to start figuring out this so will check back tomorrow with progress.
Neville
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
You're looking for an 18-ga. pink wire from the "R" terminal on the solenoid (the outboard small stud); that wire runs through the branch of the engine harness that goes up and across the firewall, and it ends up at the coil (+) terminal, crimped to the same flag terminal that has the pink wire from the ballast resistor.
Drifting
Joined: Jul 2005
Posts: 1,977
Likes: 195
From: Putnam Valley, New York. Amateur Radio Operator K2NS
What you're saying is correct, but the coil should still be getting power through the ballast resistor even when the ignition switch is in the start position. Granted, it may only be getting 6-8 volts, but it runs at that voltage, and it should start with that voltage also. The solenoid bypass is for a full 12 volts to the coil for easier starting, but the original poster says that the engine just catches as he releases the key. I think he has 2 problems--a bad ignition switch which is not providing power to the ignition circuit when it is in the "start" position, and a missing solenoid bypass circuit. When I got my car 34 years ago, the wire to the solenoid "R" terminal wasn't there, but the engine did start while the key was in the start position.
RON
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Thread Starter
Pro
Joined: Jan 2007
Posts: 524
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From: Auckland New Zealand
You're looking for an 18-ga. pink wire from the "R" terminal on the solenoid (the outboard small stud); that wire runs through the branch of the engine harness that goes up and across the firewall, and it ends up at the coil (+) terminal, crimped to the same flag terminal that has the pink wire from the ballast resistor.
Pink wire circuit was non-existent. Horn power feed was coming from run terminal, plus a few other odd connections
I have just been ferriting around in the loom between motor and firewall. I've unwound about what seems like 1000 metres of black tape!! There was an awful lot of wires in there that should not have been, some going nowhere, some twisted to others that looped back on themselves - in short MR Botchit had been there.
I decided it was an early morning job, so this morning took a deep breath and unravelled it all and removed all garbage wiring and reloomed the harness along firewall and reterminated connections.
I would say that something electrical has been added at sometime and wiring loom was hacked into. Suppose I have to kind of expect this sort of thing on a 40 year old car, but as an engineer I get a bit hacked off at some of the carnage that some people can inflict on these old cars.
Car now starts and runs fine - tick off one job.
Cheers
Neville
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Joined: Jan 2007
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From: Auckland New Zealand
