Need help with a start issue

76carrera3.0 · 07-25-2009, 03:20 PM

Well my father and I have just spent all day trying to track down the problem and we are both at our wits end. I will try to explain what is happening and hopefully some of the electrical gurus here can steer us in the right direction.
The car is a 76 carrera 3 liter and I have been experiencing a hard start problem for a long time and have been trying to track it down.
We have confirmed that we have no spark with the ignition switch in position 3 yet have spark with the switch in position 2, and if lucky enough to have everything work out the car will start and run no problems. We have tested the ignition switch and it is functioning as it should. The problem would appear to be at some point after the switch. We are stopping for a supper break right now but I will go back out in a hour or so and re check the voltages at the CD connector and the coil and points connections and then post these results in a hope that somebody will have a solution as we are completely stumped right now.
Thanks in advance for the help.

GH85Carrera · GH85Carrera's Garage

I would look at the points first. That sounds just like the problems I had with my 74 914.

76carrera3.0 · 07-25-2009, 06:54 PM

Points have less then 2000 miles on them. I pulled the distributer again tonight and the points look like new and are adjusted and should be fine. We started to check voltages tonight, and well we just became more frusterated and confused. My father worked as an electritian all his life and there is not much he cant seem to get right and he is absolutely stumped. I think if some one in the now could give us some details as to what voltages we should have at what point with the key in what ever position we could start to sort out the situation.

Once again I appreciate any help some one can give us cuase right now we are no futher ahead then we were 12 hours ago.

lucittm · lucittm's Garage

Please give us the voltage at the battery connection of the coil (+12V) with the key in all positions. Also, do you hear the CD box buzzing in all key positions?

Good Luck,
Mark (Had a 1976 911S)

crustychief · crustychief's Garage

My Volkswagen acted like your car, I think the circuit is similar. If the starter draws to much current it will do the same thing but will be exaggerated when it is hot.

76carrera3.0 · 07-25-2009, 07:51 PM

This thing is driving us nuts we have checked voltages for at least 4 hrs, we just went out and checked the voltage at the coil, and now we are seeing Zero volts in position 1, Zero volts in position 2 with points open and points closed and zero volts in start position. Which isstrange because I would swear that at one point today we had 12 volt at position 1, 12 volt at position 2, and 2.8 volts at position 3.

The CD box will whine in position 1 and 2 of the switch, whine confermed in position 3 with starter solenoid yellow wire disconnected.

I know the zeros across the board don't help much, let us know if there is anything you want checked and we will start fresh again in the am. Gotta get some shut eye it has been a 14 hr day at it all ready.

Regards.

76carrera3.0 · 07-26-2009, 06:00 AM

A morning bump and a back out to the shop to start again.

76carrera3.0 · 07-26-2009, 03:40 PM

To all those that tried to help thanks again, we finally got it figured out, turns out the POS previous owner had moved the power wire to the CD "B" terminal to a different position 8 in the front fuse box instead of position 11. This in turn would allow for 12 volts to the CD unit at position 1 and 2 of the ignition switch and only 1.8 volts in the start position of the switch, which was not enough to power up the CD unit. We moved it over to Position 11 in the fuse box and finally the problem was over. We know have 0 volts in pos 1 and 12 volts in pos 2 and 3. I have owned the car for five years and it has never let me down which is amazing, but it realistically may have been this way for the past 20 years or so, which is when the car was bought by the POS previous owner and later imported into North America when his Military tour ended.
I am just glad that we found the problem 2 men 16 hours of head scratching each, that would be one hefty bill at a wrenches shop!!!!

To all thanks again, Trevor.

pete3799 · pete3799's Garage

Don't think your problem is over yet. Your saying the car ran fine when it was wired to fuse #8
for five yrs.?(maybe 20Yrs.)
Hopefully you've cured it but I have my doubts.
Just say'n.