starter woes Options

[boeserbaer]

I have a 1974 2.0L. It has sat for a while, and I am trying to get it up to daily driver level. Presently my starter is intermittent. Symptom: turn key, and voltmeter drops, fuel pump cycles, no turnnover. It seems that the starter is creating a load, but not functioning. Then it will work every time for a while, then I get out on the road (bay area to LA), and my girlfriend is push starting me. On that subject I ran into the BEST porsche shop ever in torrance "callas rennsport". I vaguely recollect the same symptoms a few years ago, and replacing the ignition switch, does this sound right? If so It sucks to have to do it again so soon. I think that a relay or something is needed to reduce the current through the key switch?

[Dr. Roger]

when you mention a voltage drop when trying to turn it over, that indicates either a bad ground/connection at the battery/starter.... or you have a battery that is about to die.

clean contacts everywhere including at the batt.

LOAD TEST the battery.

50/50 it's one or the other. I've got $0.02 on this diagnosis.


My question to you is where are you taking the voltage reading? right on the battery posts? if so, it's your battery.
No, then it could be the other two issues.


(IMG:style_emoticons/default/biggrin.gif)

[boeserbaer]

when you mention a voltage drop when trying to turn it over, that indicates either a bad ground/connection at the battery/starter.... or you have a battery that is about to die.

clean contacts everywhere including at the batt.

LOAD TEST the battery.

50/50 it's one or the other. I've got $0.02 on this diagnosis.


My question to you is where are you taking the voltage reading? right on the battery posts? if so, it's your battery.
No, then it could be the other two issues.


(IMG:style_emoticons/default/biggrin.gif)

I am looking at my center console voltmeter (which also shows drops whenever my brake lights come on... Obviously there is excessive resistance (either internal battery, or external wiring/contact). I will be cleaning this afternoon.
Does anyone know what drop to expect across the battery posts from either headlights or brake lamps?
Also my 74 has been modified, and the seat belt relay/ckt removed. The ignition switch directly drives the solenoid (unless there is a relay behind the firewall?) This seems like bad practice due to back emf arcing the switch. Is this the normal way the starter ckt operates on non-1974 models? I am inclined to put a hot start relay in with a snubber diode/capacitor to protect the switch.

[Dr. Roger]

Wazup?

How'd it go? What did you find?

when you mention a voltage drop when trying to turn it over, that indicates either a bad ground/connection at the battery/starter.... or you have a battery that is about to die.

clean contacts everywhere including at the batt.

LOAD TEST the battery.

50/50 it's one or the other. I've got $0.02 on this diagnosis.


My question to you is where are you taking the voltage reading? right on the battery posts? if so, it's your battery.
No, then it could be the other two issues.


(IMG:style_emoticons/default/biggrin.gif)

I am looking at my center console voltmeter (which also shows drops whenever my brake lights come on... Obviously there is excessive resistance (either internal battery, or external wiring/contact). I will be cleaning this afternoon.
Does anyone know what drop to expect across the battery posts from either headlights or brake lamps?
Also my 74 has been modified, and the seat belt relay/ckt removed. The ignition switch directly drives the solenoid (unless there is a relay behind the firewall?) This seems like bad practice due to back emf arcing the switch. Is this the normal way the starter ckt operates on non-1974 models? I am inclined to put a hot start relay in with a snubber diode/capacitor to protect the switch.