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Old 09-18-2015, 02:40 PM
CHP2RA CHP2RA is offline
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Join Date: Nov 2014
Location: Lipan, TX
Cobra Make, Engine: Superformance MK III Roadster, Roush 402
Posts: 57
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Default intermittent won't crank when hot - electrical power loss

For several months I've experienced an intermittent total loss of electrical power in a hot engine start situation. I bought this car used in April, and first encountered this problem June. Took it to a local specialty car shop (recommended by Texas Cobra Club members). They found dead cells in the Optima Red Top Battery (two years old), and replaced it. Problem continued, and in August same shop performed total electrical test - all checked out EXCEPT a loose connection at the alternator. They replaced the smaller wire from the alternator to the battery with a 4-guage wire. Looks impressive, but the problem continues, intermittently. The shop is too busy now to look at it, so I'm looking for help

Superformance Cobra, Roush 402R, MSD ignition, GM 1-wire alternator

Each time it has reoccurred, the engine has been hot, and turned off for 5 to 15 minutes, and then won't start. 2 of the 3 times the car has just been unplugged from the battery tender, and driven for only15 minutes. One incident was August 18th, after driving for one hour, then sitting 15 minutes, and 'self corrected' almost immediately. Next was Aug. 28, and self corrected after 7 minutes - I tapped on the starter, not sure that helped. The last incident was September 13, and took 2 1/2 hours of my intermittently tapping on the starter & firewall solenoid, & 'jump-starting' it. In each case, I initially made the same following mistake, which was followed by the electrical power loss incident:

Hot engine. 5 - 15 minutes after stopping. With the car in gear, key inserted, turned to run, electrical power-up noise heard, fuel gauge starts to rise, turned to start and 'clicking' solenoid-like noise heard, and motor will not turn over. Fuel gauge starts to drop. No power. Move the gearshift to neutral, but it still wont start. Perhaps a sticking neutral safety switch?

In the last incident after 2 1/2 hour tapping & trying the kill switch (no sound) & jumping from another car and then from my Ford F 350 turbo-diesel, I finally heard the faint "power up" noise from under the drivers side dashboard. Turn the ignition key to run, but the fuel gauge did not rise. Car would not start. No clicking 'solenoid-like' noise. Turn the key back to accessory, and pressed the kill switch. As I pressed it, heard the solenoid-like click, then click again as I released the kill switch. Motor would not start, fuel gauge needle would not rise. Tried the kill switch several times: each time the solenoid noise clicked as I depressed the kill switch, and clicked again as I released the kill switch button. Motor still refuses to start, fuel gauge doesn't work. Finally tried holding the kill switch down with one hand while turning the ignition switch from accessory to run to start with the other hand, and the engine turned over and started. The dashboard lights wouldn't work however, and the running lights would not come on, however the headlights came on. I checked the fuses, and they are good. Turn indicator lights work.

Any thoughts or suggestions are greatly appreciated.
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