No 12 Volt to the Coil

[JJ 911SC]

After finishing detailing the car (1983 SC with an updated 1986 3.2L Engine) inside/out and replacing the Air Filter, I started the car. It idle for 5 minutes and I took it for a ride. At the end of the driveway, it "died". Push her back and start faultfinding.

I pull a spark plug wire out a plugged an old spark plug and crank it, there was no spark. Check for 12 Volt at the coil and it is missing. As I have read in a faultfinding guide, I put 12 volts directly to the coil and the car started. I check all the fuses and find one that was physically broken (not blown) but it was for the Engine Fan Compartment, which now works. I "borrow" an ignition but the problem remains. My next step is to change the Fuel Pump Relay. Also the grounding strap was broken on the engine relay panel (on the left).

It could be as simple as a wiring problem that could be hard to trace as the car was an electrical mess when the previous owner bought it.

Is there a danger to apply the 12 volts directly to the coil when I need to move her around as in bring it to a shop?

Being a 1986 Engine, could be related to the DME ECU module?

Help

[ericinboca]

After finishing detailing the car (1983 SC with an updated 1986 3.2L Engine) inside/out and replacing the Air Filter, I started the car. It idle for 5 minutes and I took it for a ride. At the end of the driveway, it "died". Push her back and start faultfinding.

I pull a spark plug wire out a plugged an old spark plug and crank it, there was no spark. Check for 12 Volt at the coil and it is missing. As I have read in a faultfinding guide, I put 12 volts directly to the coil and the car started. I check all the fuses and find one that was physically broken (not blown) but it was for the Engine Fan Compartment, which now works. I "borrow" an ignition but the problem remains. My next step is to change the Fuel Pump Relay. Also the grounding strap was broken on the engine relay panel (on the left).

It could be as simple as a wiring problem that could be hard to trace as the car was an electrical mess when the previous owner bought it.

Is there a danger to apply the 12 volts directly to the coil when I need to move her around as in bring it to a shop?

Being a 1986 Engine, could be related to the DME ECU module?

Help

Does it have a CDI? Capacitive Discharge Ignition box? the 83 SC does, and it apparantly dies often. Neighbors 83 SC had the same symptoms - turned out to be CDI - we have it rebuilt at ECUdoctors.com

[JJ 911SC]

After finishing detailing the car (1983 SC with an updated 1986 3.2L Engine) inside/out and replacing the Air Filter, I started the car. It idle for 5 minutes and I took it for a ride. At the end of the driveway, it "died". Push her back and start faultfinding.

I pull a spark plug wire out a plugged an old spark plug and crank it, there was no spark. Check for 12 Volt at the coil and it is missing. As I have read in a faultfinding guide, I put 12 volts directly to the coil and the car started. I check all the fuses and find one that was physically broken (not blown) but it was for the Engine Fan Compartment, which now works. I "borrow" an ignition but the problem remains. My next step is to change the Fuel Pump Relay. Also the grounding strap was broken on the engine relay panel (on the left).

It could be as simple as a wiring problem that could be hard to trace as the car was an electrical mess when the previous owner bought it.

Is there a danger to apply the 12 volts directly to the coil when I need to move her around as in bring it to a shop?

Being a 1986 Engine, could be related to the DME ECU module?

Help

Does it have a CDI? Capacitive Discharge Ignition box? the 83 SC does, and it apparantly dies often. Neighbors 83 SC had the same symptoms - turned out to be CDI - we have it rebuilt at ECUdoctors.com

I'll check tonigh. As the engine is a 3.2L 1986 version it may have DME ECU module.

[70Sixter]

The CDI makes a shrill hum whilest alive and working.

[wvicary]

Check all of the fuses with a test light/volt meter. They often corrode at their ends so it's best to test for voltage on both ends of the fuses. The CDI module controls the coil ground path.

[JJ 911SC]

Being a hybrid, it makes this a bit harder. The 1983 CDI engine was replaced with a 1986 3.2L so I am expecting a DME Control Unit.

I only had the car for 8 days and the repair manual is in the mail (I went with Hayes because on book covers all model (1965-1989) while I would have need two books with Bentley, 1978-1983 & 1984-1989. The previous owner bought the Bentley books but having moved twice in the last year, he is still going through the boxes.

Now I got pictures of both units so I should be able to locate them.

I though that the DME ECU module would have been under the driver seat.

[ericinboca]

Being a hybrid, it makes this a bit harder. The 1983 CDI engine was replaced with a 1986 3.2L so I am expecting a DME Control Unit.

I only had the car for 8 days and the repair manual is in the mail (I went with Hayes because on book covers all model (1965-1989) while I would have need two books with Bentley, 1978-1983 & 1984-1989. The previous owner bought the Bentley books but having moved twice in the last year, he is still going through the boxes.

Now I got pictures of both units so I should be able to locate them.

I though that the DME ECU module would have been under the driver seat.

CDI in an 83 is mounted on the left rear corner on the wheel well wall in the engine compartment. A box about 5x3 - something like that. I think there is one cable in at the bottom of it.

[JJ 911SC]

Being a hybrid, it makes this a bit harder. The 1983 CDI engine was replaced with a 1986 3.2L so I am expecting a DME Control Unit.

I only had the car for 8 days and the repair manual is in the mail (I went with Hayes because on book covers all model (1965-1989) while I would have need two books with Bentley, 1978-1983 & 1984-1989. The previous owner bought the Bentley books but having moved twice in the last year, he is still going through the boxes.

Now I got pictures of both units so I should be able to locate them.

I though that the DME ECU module would have been under the driver seat.

CDI in an 83 is mounted on the left rear corner on the wheel well wall in the engine compartment. A box about 5x3 - something like that. I think there is one cable in at the bottom of it.

Getting Closer...

I am loosing the 12 Volts between the Starter (#1) and the Coil. The attached schematic shows a Control Box (# 3), Resistor (# 8) and Resistor Relay (# 51). I need to physically locate them to take a voltage measurement. I start to suspect # 51 especially if it is the Fuel Pump Relay.

Electrical_Schematic.PDF

[JJ 911SC]

Being a hybrid, it makes this a bit harder. The 1983 CDI engine was replaced with a 1986 3.2L so I am expecting a DME Control Unit.

I only had the car for 8 days and the repair manual is in the mail (I went with Hayes because on book covers all model (1965-1989) while I would have need two books with Bentley, 1978-1983 & 1984-1989. The previous owner bought the Bentley books but having moved twice in the last year, he is still going through the boxes.

Now I got pictures of both units so I should be able to locate them.

I though that the DME ECU module would have been under the driver seat.

CDI in an 83 is mounted on the left rear corner on the wheel well wall in the engine compartment. A box about 5x3 - something like that. I think there is one cable in at the bottom of it.

Getting Closer...

I am loosing the 12 Volts between the Starter (#1) and the Coil. The attached schematic shows a Control Box (# 3), Resistor (# 8) and Resistor Relay (# 51). I need to physically locate them to take a voltage measurement. I start to suspect # 51 especially if it is the Fuel Pump Relay.

[JJ 911SC]

I did find the DME Control Unit (911 618 111 05) under the passenger seat...

[ericinboca]

I did find the DME Control Unit (911 618 111 05) under the passenger seat...

My PET says that is for an M30.21 motor - hopefully someone can tell you a few things about that motor.

[JJ 911SC]

]

The Engine Serial # starte with 64G... I think the G is for 1986. I dont' know when the 3.2L was installed in the car.

The Carfax report the 1st ower in Toronto (11 yrs), 2nd owner in Montreal (4 yrs), 3rd owner in Victoriaville (6 yrs), 4th owner in Ottawa (5 yrs) and I'm the 6th and will the last owner.

I got Odometer reading from Service Facility at 37,076 Miles in 1999 & 54,718 Miles in 2003. I got the car on the 15 June @ just over 67,000 miles.

Since I did not have the history of the engine (could have been installed at the Service Facility reported, the PPI included a compresion test and the result was from 160-170 PSI across the 6 cylender (about 6% variation).

[ericinboca]

]

The Engine Serial # starte with 64G... I think the G is for 1986. I dont' know when the 3.2L was installed in the car.

The Carfax report the 1st ower in Toronto (11 yrs), 2nd owner in Montreal (4 yrs), 3rd owner in Victoriaville (6 yrs), 4th owner in Ottawa (5 yrs) and I'm the 6th and will the last owner.

I got Odometer reading from Service Facility at 37,076 Miles in 1999 & 54,718 Miles in 2003. I got the car on the 15 June @ just over 67,000 miles.

Since I did not have the history of the engine (could have been installed at the Service Facility reported, the PPI included a compresion test and the result was from 160-170 PSI across the 6 cylender (about 6% variation).

64G00001 through 10000 matches 1986 3.2L - and you have the right part number for the DME for that motor. I've noticed wvicary knows there older 911s really, really well. Wonder if he can pass along any advice. He helped me with an 83.

[JJ 911SC]

Well, I should have paid close attention to "wvicary” posting on the 23 June...

On Saturday, I put a new DME relay and a Gas Pump Relay with the same result. So I decided to re-start from scratch.

So, I decided to re-check the fuse box but using voltage vice continuity as per "wvicary" posting. One fuse had 12 Volts on one side but 0 Volt on the other side post. I check in the middle of the fuse and 12 Volts was present but nothing on the post, I took a close look at the fuse and it was physically broken (not melted) at one end (this is as per the one that was on the Engine Compartment Blower) .

I put a new fuse in (Indicator Signal and Back Up Light position) and turn the ignition and "voilas" the engine started... but would not stop even when I took the key out (had to unplug the DME relay to get it stop).

I started to go over all the events... When the car first stall, my first step was to check the fuse box, right away I noticed that there was NO fuse in the "Fuel Pump" location so I though that it had sprung out and it would fix the problem but it did not.

So, I decided to remove the Fuel Pump fuse. So I am back to the way when I got the car. It is starting and stopping as per normal and there is no fuse in the Gas Pump position.

If you got a Fuel Pump relay, is there also supposed to be a fuse in the Gas Pump position? The car is running as per normal without one, the way I got the car. I will track down where they actually (probably done during the engine upgrade) running the pump on and fixup the mess.

As per what it seem to be a Porsche Standard Operating Procedure, I now have good spare Fuel Pump and DME relays in the glove box along will spare fuses and fan belt

On Sunday, I attended the Carleton Place car show. There was over 200 cars with about 25 imports. I took 3rd place in the Import Category, the red one took 2nd.

Thanks to all, involve.

J.J.

[wvicary]

Glad you got it sorted.