Unique Electrical Prob. Any Suggestions
Thread Starter
1st Gear
Joined: Sep 2006
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Unique Electrical Prob. Any Suggestions
Sorry about this lenghty post but waaaaaa!
The car...98 targa 6 speed, 50,000 miles, long tube headers, corsa exhaust, vortex intake plumbing and other small stuff. Charging system components are new and tested, optima red top, valeo alt, starter.
The problem...The car being cold does not seem to keep this from happening but it might happen more warm. Key on, not running Voltage reading at the bat can be 12.5+ and the IPC can read anywhere 11.2 to 10.5. When the key is in the start position actual battery voltage generally stays above 12 but dash reading drops in the toilet. It seems if my dash reading is below 11 volts it usually wont crank much, what's weird is that if I hold the key on the start position it will bump the starter numerouse times with small pauses and sometimes take off and start, yesterday it just died on me but restarted afer 20 minutes or so. Whatever is going on seems to be tied to the ipc voltage reading but not always. By the way I don't get any darn codes! Its almost like an ecu of some sort is loosing its voltage and powering down under a load because of low supply power to it, bad ground or just a bad box!
What I have done to try and remedy the prob... Cleaned and ohmed for resistance power and ground wires and ground buss connectors.(2 front engine compartment ground busses, 2 main engine block grounds,both interior kick panel grounds). Removed and inspected pins and plugs on both ecu's under the battery, measured voltages all over engine compartment and passenger foot well fuse panels(key on looks good). The only place I have found some what low voltage was on one of the ignition switch wires(pin location D on the white plug around 11 v). When the car won't crank my voltage stays strong at both fuse panel main lugs. I do have a good background in automotive electrical but I am just learning the vette (just bought it for a song but don't have schematics or manual for it yet). I would love to put more miles on my new car but I am scared to go anywhere now. Any help would be greatly appreciated and hopefully I can return the favor!
The car...98 targa 6 speed, 50,000 miles, long tube headers, corsa exhaust, vortex intake plumbing and other small stuff. Charging system components are new and tested, optima red top, valeo alt, starter.
The problem...The car being cold does not seem to keep this from happening but it might happen more warm. Key on, not running Voltage reading at the bat can be 12.5+ and the IPC can read anywhere 11.2 to 10.5. When the key is in the start position actual battery voltage generally stays above 12 but dash reading drops in the toilet. It seems if my dash reading is below 11 volts it usually wont crank much, what's weird is that if I hold the key on the start position it will bump the starter numerouse times with small pauses and sometimes take off and start, yesterday it just died on me but restarted afer 20 minutes or so. Whatever is going on seems to be tied to the ipc voltage reading but not always. By the way I don't get any darn codes! Its almost like an ecu of some sort is loosing its voltage and powering down under a load because of low supply power to it, bad ground or just a bad box!
What I have done to try and remedy the prob... Cleaned and ohmed for resistance power and ground wires and ground buss connectors.(2 front engine compartment ground busses, 2 main engine block grounds,both interior kick panel grounds). Removed and inspected pins and plugs on both ecu's under the battery, measured voltages all over engine compartment and passenger foot well fuse panels(key on looks good). The only place I have found some what low voltage was on one of the ignition switch wires(pin location D on the white plug around 11 v). When the car won't crank my voltage stays strong at both fuse panel main lugs. I do have a good background in automotive electrical but I am just learning the vette (just bought it for a song but don't have schematics or manual for it yet). I would love to put more miles on my new car but I am scared to go anywhere now. Any help would be greatly appreciated and hopefully I can return the favor!
Tech Contributor
Joined: Oct 1999
Posts: 41,063
Likes: 9,827
From: Charlotte, NC (formerly Endicott, NY)
It sounds like you may have a short in the starter circuit. With a short the current draw through the starter will increase resulting in the lower voltage reading you are seeing on the DIC or gauge.
Bill
Bill
