Ignition switch cap wiring hot/+12v starter wire (black/white) blowing at cap.

Discuss the RB20, RB25 and RB26 series engines.
Dustin_S
Posts: 3
Joined: Wed Sep 12, 2007 1:54 pm
Car: Nissan 240SX S13

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I have a 93 S13 with an RB25DET series 2 swap. Motor is mechanically stock with Greddy Front-facing plenum (one year in the car) and RS-Enthalpy ECU (three years in the car).

Did the motor swap back in 2013. Within the last two years, the car has blown out the black/white starter +12v wire on the end of the ignition cap three times. The most recent occurrence was a week ago last Wednesday. I've also noticed the black wiring bundle from the cap to the clip under the dash console gets extremely hot and when I replaced the cap this last time, trying to turn on the car blew the ignition switch fuse. The two plastic clips had also melted together, requiring use of a flathead screwdriver to force them apart. Obviously this is unhealthy for the car and a big fire hazard which is bad enough, but also about 12 inches from my junk, which is a huge aggravating circumstance.

The grounds on my starter, engine, and connections to the pictured fuse box look fine to me, but I reconditioned them anyway. The car starts easier and runs smoother, but the ignition heat issue remains.

I've also seen it suggested elsewhere on the internet and in this thread that the electric fans can cause an overheating issue in some cases. From what I understand, fans wired to a source related to the ignition system can draw the power through the starter wiring, increasing the load that system has to handle and causing the overheating. My fans are wired into a black w/red stripe wire (circled) coming from the passenger side relay box. The two red wires (Red "X") power my fans. The fans are grounded to the front brace that holds the hood release.

And now you guys know everything I know about the electrical problem. Right now, I'm leaning towards getting a electric fan relay kit so as to take some of the strain off the ignition system's electrical grid.

I welcome your feedback, thoughts, ideas, and tips! Thanks Nicoclub.

Edit: It was indeed the electric fans. I disconnected the splice from my ignition switch wiring, started the car, and after ten minutes of idling, the ignition switch wires were still cool to the touch. This is good because it means no more fire hazard. This is bad because i'm not sure if my car will refrain from overheating during driving. I know I can install a pair of relays to power the fans when the car is on, but i still have to, ya know, *buy* them. Still, this problem of two years is solved.... :woot:


macgiver
Posts: 1612
Joined: Wed Jul 04, 2007 10:21 am

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mac, yes your on the right path - separating off the heavy-current device('s), which are overloading that ign Sw. , by installing relays.The key is to determine ALL the culprets , and I would suggest an inexpensive (NOT CHEAP though) "CLAMP-ON " - DC capable Ammeter which would be invaluable for determining actual current (the high dollar RMS ver. not needed for DC) of ANY WIRE - and WITHOUT needing to break & insert for "series" in-line probes, in order to get readings ! :yesnod


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