Starter relay or no starter relay, Been reading up for an hour and still don't know!! Options

[stugray]

You have to admit... installing the "helper" relay to drive the solenoid is kind of funny since the solenoid is a relay itself:

12V 12V 12V
| | |
Ign Switch -> Relay -> Relay -> Starter


Hmm... my whitespace in the lines above doesnt show up.
Anyway I was trying to show that a separate 12V source feeds each relay in that chain

[Mark Henry]

You have to admit... installing the "helper" relay to drive the solenoid is kind of funny since the solenoid is a relay itself:

12V 12V 12V
| | |
Ign Switch -> Relay -> Relay -> Starter


Hmm... my whitespace in the lines above doesnt show up.
Anyway I was trying to show that a separate 12V source feeds each relay in that chain

Not really, the Bosch solenoid takes a full 9V to make it open. When the car was new, or in it's expected life of less than 10 years, the stock system has no problem with this.
The ford solenoid takes less than 3V to open, giving a full 12V to the Bosch solenoid, causing way less "strain" on the system.
You can't just replace the Bosch solenoid as it also has the bendex.

This fix has been around since the 70's, on the bug maybe even the 60's, it's not rocket science.

[Tom]

Actually the normal state of the relay is open, and when power is applied, it closes.
Minor point, but could confuse some new person.
I spent a good deal of time thinking about the diode remedy to suppress the inductive spike from the solenoid. I do believe the correct size diode would work, however, how would one know it is still working a week/month/year later? You wouldn't, until suddenly you have a start issue and find out during troubleshooting that the problem was the diode had failed. With the relay, if it fails, you know right away. So I think the relay remedy is the best all around fix in this case.
There are many different relays that will do the job. For whatever it is worth, I prefer one of the Bosch style as it requires no tools to replace one in an emergency. Just unplug the spade lugs from the old one and plug them into the new one. 2 minutes and a zip tie and you're back on the road. You can finish the installation when you get home.
Tom

[eyesright]

VW/Porsche built up a lot of good karma by bringing out the 914. Since then a little bad karma has been chipping away...


1 Shoulda had fender liners.
2 Shoulda had cable shifters. (Well, okay, but they could have invented them!)
3 Shoulda had a starter switch relay.
4 Shoulda had better window/top seals.
5 Should NOT have quit making them! (That was the worst offence!!!)

So, okay everybody, next time you are in there/under there, clean all the connectors and grounds, replace the ground straps and battery leads, add a relay to save your ignition switch. Yours and mine, now, are working fine, but do this and it will for the next guy too, in, say...2050 or so. Good karma. And a good excuse to crawl under your/my car that is 95%donesoIcanputoffworkingonitsomemore.

PS very good and informative discussion...