Quote:
Originally Posted by scottfab
Not a bad idea as long as the FET is clamped with a zener to protect it from the inductive kick of the starter solenoid. (similar to class D amps).
|
Hmmmm..... Well, that might work, but would have consequences. Due to the fwd bias threshold, in a situation where the starter is already "a bit finicky" (w/regard to minimum voltage requirements). I don't know if I want to put a healthy diode in series with the output. Maybe the simple "filter" capacitor (like they do on distributor/coil ignition) to absorb the "kick" might be sufficient, ya think?
Quote:
Originally Posted by scottfab
There will always be this pressure on the thrust bearing either before start or after. Failure will not be due to pressure on the bearing but the spin of the bearing dry which would happen regardless. (IMHO)
|
I believe Marc is referring to the force imparted on the TO bearing to release the pressure on the clutch disc, which acts on the crankshaft via the flywheel when the clutch pedal is engaged.
NOT pressing on the clutch would prevent this force from acting on the end of the crankshaft and the thrust bearing. Bypassing the clutch interlock switch would allow the motor to start w/o end thrust. Starter load would go up slightly as the transmission would be turned w/o the clutch being disengaged. (Prolly not so much on a DD, or even one driven once a week. But, once a month or less, and in the winter months especially? Makes sense.
Quote:
Originally Posted by scottfab
A noted and well know author and owner of a ZR-1 once said of the GM designers, "these are highly skilled, highly paid engineers that focused on these designs for years. They know more than shade tree mechanics." (paraphrased) That statement comes to me every time is see someone on this forum struggle with some of the more notorious failures. Fact is we've had decades now of experience that those engineers did not have. Improvements are not only needed but necessary for the good of the car. However, I've always made my mods "backoutable" just in case it's important to the next owner. (very likely after I'm gone)
|
People aren't perfect, and bean-counters force engineering compromises to be made.
Truth is where you find it, beit in some college level engineering course, or discovered by a "shade tree mechanic".
Serendipity is a heck of a good teacher, I find!!
Back to the OPs question: All this said, I DON'T think it is the interlock switch anyway. I agree w/
scottfab. I suspect a connection issue (either internal to the starter or at the battery terminals or ground terminal). If it were the interlock, connecting jumper cables to the battery wouldn't result in it starting.
That said, electrical problems often will only show up when devices get hot. So, a cold starter might test OK, but after being heat soaked, things might turn up that weren't there before!
P.