Any electrical geniuses out there?

[sierraspider]

My 82 FI spider is suffering from intermittent starting problems. Won't turn over at the weirdest times. Battery is new and when this happens it just takes a very quick jump and it fires right up. So what I'm looking for is a logical way to test and diagnose the problem. Voltage drain, flat spot in starter or what? Electrical issues not my forte, so I'm looking for a systematic process of elimination to determine cause. Any thoughts would be greatly appreciated.

[micbrody]

I have an 81 FI. I have found that the starter really needs all the amps from the battery to get moving (I am assuming when you say "won't turn over", that means starter not energizing. Like most electrical problems, it usually is from bad electrical connections leading to greater resistance. If it turns over right away with an additional source of electrical power, then the first thing to do is to clean the contacts of wires on starter, brown spade connector on back of ignition switch (hell, just clean all of them); the ignition switch plastic harness connector; and the battery terminals. I use a dremel tool with a wire disk brush; and then I spray De-Ox. Also, if you have not already done it, clean up the ground connections (on my car, there are three grounding pods( under hood inside left fender, right fender, and under dash to the right of ignitiin switch. Then there are wires that ground fuel injectors; and on that grounds tranny to chassis.

[narfire]

I had a lousy ground connection at the battery ( not tight) that let the ignition lights come on but starter did not turn.
Just check all the connections are tight and clean for a start. (pun intended)

[sierraspider]

Makes perfect sense.I'll get to cleaning the contacts and let you know how it goes.

Thanks

[81SPIDERMATT]

pink wire that goes to small spade on starter being dirty gave me fits just like that

[DieselSpider]

Chase it down before it goes too far.

I had the starter solenoid die on mine several months ago so I cleaned it up the wiring and replaced the solenoid and thought all was fine until it started doing the same as yours.

Bottom line is low voltage over time has damaged the starter solenoid again so it needs to be replaced a second time. I did the Brown Wire fix this weekend along with installed a 40 amp relay off the main lug on a 30 amp fuse just to power the starter solenoid. Will order the new solenoid for the Hitachi Reduction starter on the Diesel today.

Brown Wire Fix:
http://www.mirafiori.com/faq/content/bwfix/bwfix.htm