You say 1973 model, what intake? CIS is slightly different than earlier.
Cyl head temp sensor is tough to get to and needs slotted socket to clear attached wire, old and new style are different sizes. I'd hold off till it is running to see if it is a problem.
Yellow/Bk and Brown Aux. engine fan, not used if heat is backdated and fan eliminated.
Green wire, A/C or O2 sensor? My harness was a hacked euro so some can be difficult, mine was not set up for O2, which I added later.

First connector by DME, do you have the altitude correction sensor?
http://forums.pelicanparts.com/uploa...1376860704.jpg

I do not have that altitude correction sensor - not that I know of. It is not present near the DME itself on the drivers side floor.

The engine is a Euro '85 model 3.2. It has backdated heat exchangers and a Steve Wong euro model chip.

Even the Row had the Alt correction sensor. It is typically mounted near the dme. As far as a special socket, go to Auto zone and buy a cheap one and cut it. It works fine. Cut the wire for taking it out and use the other socket for installing. Check the resistance is in spec on the cht sensor first.

The Gry/W is not used.
The twisted and capped red wire would have been the feed to the CDI box.
The R/W, R/Bk are the rear defroster.
Brn/Bk, not needed.

The altitude correction module is open below 3000 feet, so having the wires disconnected should not be an issue in Georgia.

The green wire at the coil should be pin 1 of the 35 pin connector at the ECU.

Pin 5, 16, 17 of the ECU connector is ground. The ECU gets it's ground in the group of wires at the left rear of the motor intake rail, which means that the tranny ground strap must be connected.

Pin 13 is CHT sensor. (the top of the 3 motor connectors)

Pin 27 of ECU is speed sensor. (I think the middle of the 3 motor connectors)

Pin 25 & 26 is reference mark.(I think the bottom of the 3 motor connectors)

When I had bad solder joints at the ECU, I have been able to start the car by tapping on the ECU and DME when turning the key.

Mike

The Bl/Y and Brn/W wires are for Sportmatic and not needed.
As Mike wrote, altitude sensor won't keep it from running.
Interesting that it started once and now nothing. Heres a trouble shooting chart.
http://forums.pelicanparts.com/uploa...1376930226.jpg

Thanks for the graph for testing.... tough to use some of it because I do not know where the noted sensor is located.

Which items would prevent spark? The coil shows battery voltage, but a test spark plug confirms that the car is getting no spark. So - what specifically could be wrong that would prevent spark?

My father and I both have been digging into this - we went through all of the tests in table F that E Sully posted and found no problems. The only test we could not complete was the one for the ignition coil because my volt meter cannot show a "pulse voltage signal".

We definitely have no spark. I took the DME out and apart again and checked everything, no issues noted. The DME relay appears to be working fine. I cannot find anything that would prevent the car from running - but there is definitely no spark.

I am at a loss. I guess its off to a Porsche shop and a big bill. :( Totally infuriating given that it ran the first time I turned the switch and then refused.

I am wondering if the coil went bad? How can I determine if there is an internal failure in the coil that is causing this?

Bentley says the coil should read ~0 ohms across the + and - screw terminals, and 5000 to 8700 ohms from the screw + to the high voltage connector that goes to the cap.

Mike

PS - the speed (DG) and reference (BG) sensors can read good, but not be set correctly. If the reference isn't seeing TDC, the ECU won't know when to fire the plug. Both sensors should be set to 0.031" from the teeth.

I will test the coil, thanks for the help on how and what to look for.

Can those sensors be adjusted with the engine in the car? Where are they located and how best to reach if it is possible?

Thanks!

Terry

http://forums.pelicanparts.com/uploa...1376962584.jpg

There's some threads about this. I think I loosened the 2 bracket bolts, put some shim stock under the sensors, shoved the bracket down, (with engine at TDC), and tightened the bolts. It's not easy to get to - removing the rear left wheel helps.

Mike

Mike - In that photo, it appears that measuring the actual gap so you can adjust it to spec would not be possible with the engine in the car nor with the transmission attached to the engine. It appears that the engine is out of the car and the transmission is detached. I cannot see how one would be able to use a feeler gauge to set that gap correctly with the engine in the car, but I will jack her up again and check it out later today.

I also cannot see how that setting could be the issue given that the car ran and then quit, but at this point I cannot come up with anything that makes any sense.

The green wire that is shown in the wiring diagram I made and posted - noted as being a strange wire with an insulated wire running inside another insulated wire - that wire has continuity with the green wire at the coil. No idea what it was intended for.

Btw - car was CIS originally.

Yes this is a pic with the engine/trans separated, but you can access the sensors with the engine in.

If you study the picture, you'll see the two sensors sit in an bracket, and it's the adjustment of this bracket that sets the gap. Once the bracket is in the right place, the sensors can be removed without disturbing the bracket.

To reset the gap with the engine installed, the trick is to remove the sensor bracket with sensors, and glue pieces of paper to the sensor tips. Reinstall and press them against the flywheel, the paper will give you your gap. Once the engine starts the paper will tear away. The glue or paper residue if any remains will not affect the sensors.

HTH,
Chuck.H
'89 TurboLookTarga, 361k miles

Chuck.H
Good idea about gluing paper to the sensor.

Tspringer
I may have given you poor instructions about the reference sensor - You set the sensor gap when the TDC pin is at the sensor (see pic), the engine may NOT be at TDC.

http://forums.pelicanparts.com/uploa...1377005159.jpg

I agree that this doesn't make sense, because the car ran before the seat went in. If the bracket that holds the sensors is tight, I'd look elsewhere for the cause. I've had the same symptoms with bad solder joints on the ECU - it will run, then not. My thinking keep going back to the DME and ECU under the seat. The green wire at the coil should be pin 1 of the ECU connector under the seat.

Mike

I tested the coil as per instructions - the coil itself does not have any + or - markings on it for the terminals. Across the two screw terminals there are 0 ohms. With a lead on the high voltage output connection and the other lead on the black wire terminal I get about 7100 ohms. BUT - across the high voltage output lead and the green wire terminal I get about 6900 ohms.

Is this correct? Should I get a reading from either terminal and the high voltage output?

I do have continuity between the green coil wire and terminal 1 at the DME plug and also continuity between the black coil wire and DME relay plug. I also tried jumpering the DME relay as linked in the other thread and that made no difference.

Seems its either a bad DME or bad coil.

I checked my spare coil, and it reads ~6k ohms from either screw terminal to the high voltage connection, just like yours.

It sounds like you have the correct wires at the coil. If you have completed Sully's troubleshooting chart, my guess is the ECU (ECM).

Mike

Ok - maximum frustration.... no progress. Grrrrrrrrr

I took the DME apart checking for any arcing marks or breaks in the circuit board or anything I could identify as a problem - found nothing, it looks perfect.

With the GREEN wire disconnected from the coil and an old needle style volt meter attached to the green wire, when the car is turning over attempting to start I DO NOT have any pulse signal indicated. I see voltage - but no pulsing at all. This would seem to indicate that the DME is not sending a signal to the coil for it to pulse/fire spark plugs.

There is no arcing or other problems with the plug wires or distributor cap.

I see nothing wrong with the connections going to the reference sensors. Given that the car did initially run, I cannot think of any reason why something relative to these sensors could have changed.

??? If something is not correct relative to the reference sensors - would that cause the DME to NOT send a fire signal to the coil?

What other defective sensors or engine connections would cause the DME to not trigger the coil?

Is there any way to figure out whether the issue is something other than the DME without sending the DME out for testing? IF it has to go out for testing - who is cheapest / best / fastest ?

I just cannot get over why did it run and then refuse??? Just makes no sense. The car was sitting for 2 years... but then it fired right up? Second attempt - nothing and no spark since.

Any suggestions or ideas are greatly appreciated!

I had a similar problem with my DME when I did my swap. Mine was a no start from the beginning though. I was fortunate that the local Porsche shop was good enough to test my DME in a running car they had at the shop. Mine was a no start in their car, so I knew I had to send it for repairs, and an upgrade to the later style chip while it was being done.

E Sully - where did you send it for repairs and upgrade?

I am going to do more testing this weekend, but really don't know what to look for at this point. I do not know if a bad injector connection or such would cause no spark? All I really know for sure is that there is no pulse signal going to the coil and thus there is no spark.

I will try calling around to local shops on Monday to see if they have any 3.2 Carrera's in that they would test my DME in. What years 3.2 with DME would work to test this?