OK, this is what happens, have run 912 with no battery or generator issues for a couple of years and 3000 miles. On a couple of long journeys recently engine cuts out and the battery is flat. No charging warning light just a big backfire and then cut out. Restart and run on jump pack for a few miles and battery seems to charge and will restart the car again a little later. Running luminition and Halfords 330 amp battery. Any thoughts?
Thought about alternator upgrade, I have heard that there is a cheaper way of doing this than the whole kit. Any wisdom out there?
Silverfox
Flat battery while driving
Flat battery while driving
Silverfox
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
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Strictly
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- Location: Newquay, Cornwall
My starting point would be to
A) Check battery terminals for tightness and good clean contact, also check earth strap connection to chassis. I had a car once with similar issues, turned out the battery terminals were both loose, so it wasn't really charging the battery.
B) I would then move on to the gen/alt. I'm a bit hazy on how, but start by checking its output with a multimeter. I'm sure its either battery terminals, or related to the generator/voltage regulator. If the output is low, its fan belt tension or in the commuter/brushes inside the geny - if its all over the place, its probably the regulator.
An alternator charges the engine at idle speed and above. A generator needs to be at least 1500rpm to start producing a good charge, so if your driving on short journeys with lots of idling then alternator makes sense, but if your doing regular medium trips (15 - 20 miles) then a generator should be fine. Ive actually got a 356, so apologies not sure what a 912 runs, although the engine is similar. The principle is the same anyhow.
Luke
A) Check battery terminals for tightness and good clean contact, also check earth strap connection to chassis. I had a car once with similar issues, turned out the battery terminals were both loose, so it wasn't really charging the battery.
B) I would then move on to the gen/alt. I'm a bit hazy on how, but start by checking its output with a multimeter. I'm sure its either battery terminals, or related to the generator/voltage regulator. If the output is low, its fan belt tension or in the commuter/brushes inside the geny - if its all over the place, its probably the regulator.
An alternator charges the engine at idle speed and above. A generator needs to be at least 1500rpm to start producing a good charge, so if your driving on short journeys with lots of idling then alternator makes sense, but if your doing regular medium trips (15 - 20 miles) then a generator should be fine. Ive actually got a 356, so apologies not sure what a 912 runs, although the engine is similar. The principle is the same anyhow.
Luke
Had a wonderful drive this morning in the Borders, fantastic roads and over 100 miles 912 running beautifully. Then this cutting out started again eventually stopping completely. No power as if battery flat. However battery is fine and you can crank engine from aux wire in engine bay! Eventually found loose wire on battery terminal, the smaller wire that has it's own fastening. Problem solved, well know, I now have an ignition light staying on despite charging seeming ok.
Any thoughts, could the control box be damaged because of the constant on off caused by the loose connection?
Silverfox
Any thoughts, could the control box be damaged because of the constant on off caused by the loose connection?
Silverfox
Silverfox
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
If I remember correctly, the gererator light works by linking a bulb between the dyno output and the battery terminal. If the batery has high volts that the dyno then the bulb lights. If the wire to the battery was disconnected, the warning light wouldn't come on.
So, I'd get out a voltmeter and measure at the dyno/alt the output (off idle). Then check the output of the regulator. Beyond that, you need a copy of the wiring diagram and some methodical diagnostics.
It might be an intermittant issue which is, of course, a pain in the @$$.
So, I'd get out a voltmeter and measure at the dyno/alt the output (off idle). Then check the output of the regulator. Beyond that, you need a copy of the wiring diagram and some methodical diagnostics.
It might be an intermittant issue which is, of course, a pain in the @$$.
I had another thought about this....
If the car cuts out and will not restart but the Battery is full....
Does the starter turn the engine over?
If you can short an "aux" lead to the dissy and then restart....
In that situation, I'd first check for twelve Volts at both fuse 1 & 2 (input side, take the fuses out to isolate it) when the ignition is switched on. The feed for fuse 2 comes straight from the battery. The feed for fuse 1 is the "fuse 2 input side" via the ignition switch.
If the fuse 1 input side is "cold" then I'd suspect the ignition switch (or associated wiring) is faulty. There is the possibility of a big short messing with things (no fuses between here and the battery) so to confirm, remove the two red wires from the fuse 1 input (ignore the blue with yellow stripe) and check to see if one is reading 12V (the other connects to the coil) while the ignition switch is on.
If just the ignition feed from the switch was faulty, then the aux power lines could still be live and you could power the coil from one of those (what I assume happened previously).
As a bonus....... The blue with yellow stripe wire mentioned above (connects to 12V ignition switch output), is on one side of the generator warning light. The other side attaches to the regulator so if terminal 61 has an output of "some" Volts and ignition switch is duff (& you have powered the coil via another wire, removing the normal wire), then the power will flow through the gererator warning bulb (lighting it) and through fuse 2 on a long route to ground.
Good luck!
If the car cuts out and will not restart but the Battery is full....
Does the starter turn the engine over?
If you can short an "aux" lead to the dissy and then restart....
In that situation, I'd first check for twelve Volts at both fuse 1 & 2 (input side, take the fuses out to isolate it) when the ignition is switched on. The feed for fuse 2 comes straight from the battery. The feed for fuse 1 is the "fuse 2 input side" via the ignition switch.
If the fuse 1 input side is "cold" then I'd suspect the ignition switch (or associated wiring) is faulty. There is the possibility of a big short messing with things (no fuses between here and the battery) so to confirm, remove the two red wires from the fuse 1 input (ignore the blue with yellow stripe) and check to see if one is reading 12V (the other connects to the coil) while the ignition switch is on.
If just the ignition feed from the switch was faulty, then the aux power lines could still be live and you could power the coil from one of those (what I assume happened previously).
As a bonus....... The blue with yellow stripe wire mentioned above (connects to 12V ignition switch output), is on one side of the generator warning light. The other side attaches to the regulator so if terminal 61 has an output of "some" Volts and ignition switch is duff (& you have powered the coil via another wire, removing the normal wire), then the power will flow through the gererator warning bulb (lighting it) and through fuse 2 on a long route to ground.
Good luck!
Thanks Bruce M
Two separate problems, small black wire in battery terminal corroded causing intermittent loos of power to ignition. I think that this has then caused a the generator to fail. Getting no voltage on test and when run as motor really struggling. All stripped out tonight and now scratching my head. Thinking about alternator conversion.
Thanks for your ideas.
Two separate problems, small black wire in battery terminal corroded causing intermittent loos of power to ignition. I think that this has then caused a the generator to fail. Getting no voltage on test and when run as motor really struggling. All stripped out tonight and now scratching my head. Thinking about alternator conversion.
Thanks for your ideas.
Silverfox
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
How are the brushes in the dyno looking?
you can test the dyno on the bench with an ohmmeter but it is a faf.
Run as a motor, the dyno should be smooth but not that fast (might need a nudge to start it).
If you need some local assistance, I can probably point you in a good direction although it sounds like you are getting stuck in.
Is there 2 black wires attached to the battery? According to the wiring diagram, one is the feed to the starter and the other is the main power line to the fuse box.
you can test the dyno on the bench with an ohmmeter but it is a faf.
Run as a motor, the dyno should be smooth but not that fast (might need a nudge to start it).
If you need some local assistance, I can probably point you in a good direction although it sounds like you are getting stuck in.
Is there 2 black wires attached to the battery? According to the wiring diagram, one is the feed to the starter and the other is the main power line to the fuse box.
Update, generator and regulator ok, must be a wiring problem, will refit next week and start again. I am thinking how I can convince myself it is wiring. If I run a cable from the regulator to the battery isolating the loom the light should go out? I will then have to focus on the loom. Never was good at auto electrics!
Silverfox
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
Generator tested and refitted with solid state regulator from Roger bray. After some fiddling around I now have no ign warning light at all. There is a blue/green live when ignition on cable not connected behind instruments, have I pulled it off? Where should it connect?
Regardless I think I still have the problem as rigging up a test light between battery and voltage regulator test light remains on when running. There does seem to be some charge to battery as voltmeter records a small increase in voltage when engine revved.
I reman suspicious of the regulator, the original is defiantly shot as the resister wire on the back is broken, unsure about the new one as it is a different part.
Any wisdom BruceM?
Regardless I think I still have the problem as rigging up a test light between battery and voltage regulator test light remains on when running. There does seem to be some charge to battery as voltmeter records a small increase in voltage when engine revved.
I reman suspicious of the regulator, the original is defiantly shot as the resister wire on the back is broken, unsure about the new one as it is a different part.
Any wisdom BruceM?
Silverfox
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
Porsche 912 - 1968
Porsche 914 - 1974
Volvo PV544 - 1959
I'll give it a shot.....
With the engine off, battery volts should be 11-12v. Start the engine and rev to 2000rpm. The voltage across the battery should be higher, circa 14v but less with high load (all lights on, etc).
For a proper test, disconnect the b+ wire from the regulator (don't let the loose wire short out against anything). Then measure the volt between the b+ terminal and ground at 2000rpm. This is a "no load test" and should measure 13.5-14.5v I think. Then pull the coil 12v wire off and as the engine dies watch the voltmeter. The volts should drop to zero just before the engine stops turning (cut out function of regulator).
Beyond the voltage tests you need to look at amps if you still think there is a problem. This is easier with a dc clamp meter than a normal meter.
Not sure about the green/blue wire as it isn't on the wiring diagram commonly available. Can you see where it leads?
When you got the test bulb to light between the regulator and the battery which connections did you link to? If you connect a test bulb between b+ and 61 on the regulator, it should behave like the ignition warning light.
Hope that helps.
With the engine off, battery volts should be 11-12v. Start the engine and rev to 2000rpm. The voltage across the battery should be higher, circa 14v but less with high load (all lights on, etc).
For a proper test, disconnect the b+ wire from the regulator (don't let the loose wire short out against anything). Then measure the volt between the b+ terminal and ground at 2000rpm. This is a "no load test" and should measure 13.5-14.5v I think. Then pull the coil 12v wire off and as the engine dies watch the voltmeter. The volts should drop to zero just before the engine stops turning (cut out function of regulator).
Beyond the voltage tests you need to look at amps if you still think there is a problem. This is easier with a dc clamp meter than a normal meter.
Not sure about the green/blue wire as it isn't on the wiring diagram commonly available. Can you see where it leads?
When you got the test bulb to light between the regulator and the battery which connections did you link to? If you connect a test bulb between b+ and 61 on the regulator, it should behave like the ignition warning light.
Hope that helps.