What The Heck Do I Do Now?, I hate electrical Options

[fly]

Here is a good one for all of you electrical masters. The starter on my car went out when the bendix stayed engaged. SO. I put in the new starter, new battery. This is a 75 1.8 with the 2.0 starter (the one with out the shaft).

New starter installed the car turned over well. Cranked 5 or 6 times while the fuel pump fed the injectors. Immediately turned the key to start the 2nd time and nothing happened.

Basically what i have is a car that will start 5% of the time on its own. 95% you just hear the feul pump working. Tested all the wires with a friend who seems to understand more than I do. The yellow wire on the starter shows 12.7 volts when the key is engaged. Under a load it drops to 9.7 volts. Is this enough to close the circuit on the starter? Does the Yellow wire go direct from the key switch to the starter?
I thought about replacing the entire harness. We bypassed the ignition and the same results. How is it possible for the car to randomly start perfect, then nothing for the next 20 tries?

Has anyone had this experience? I am out of ideas and tests to perform. Or does anyone want to buy a clean 75

Any help will be greatly appreciated

Mike
925-705-2030

[Tom]

You can send your car to me! I can't pay any thing for it now, maybe next year. Just kidding. Your car looks great. Wish mine looked half that nice.
With the starter working sometimes, other times not, I would say you have some bad connections somewhere. Have you checked all of the connections from the ignition switch to the solenoid? Remember the seat belt relay under the passenger seat. Also as Andy said, make sure that trans ground is good!
Electricity is funny, no load and under load readings can mislead you. If you are getting battery voltage on the yellow wire when you turn the ignition switch to the start position, then the voltage is OK under no load conditions( large yellow wire disconnected fron the solenoid)?.
If that is true, then hook up the yellow wire to the solenoid and take the reading again. If the under load readings are too low, the solenoid may not work. Try to eliminate the long circuit by using a jumper wire from battery( the cable from the battery to solenoid would be OK as long as it's connections are good) to the spade terminal where the yellow wire went after disconnecting the yellow wire. Be careful when doing this as you will be under the car!! If you have access to a remote starter switch that would be best. If the solenoid works and starter starts, then you have some bad connections in the long run from fuse panel to ignition switch to seat belt relay to 14 pin connector on relay board to 12 pin connector on relay board. Any connection in this path can be dirty,corroded enough to drop too much voltage. If the connection is so bad that it is droping voltage, it certainly will not allow enough current to flow to activate the solenoid.
Hope this helps, feel free to PM me if you have questions.
Tom