T&T Racing

The wire key to the 9 pin connector, early for 1984 year

orig944

Thanks for the update, pin 4 is actually black/grey on the schematic (damn my eyes.) I think the early cars (California only) used a two pin connector for the o2 sensor heater, with wire colors not specified on the schematic.

Edit: This one: https://forums.pelicanparts.com/pors...onnection.html

T&T Racing

Yes on the cut wires, the non cut wires are low current signal wires to instruments and are ok

Acantor

Ok cool I have some more interesting wiring issues with this car that I need to address, but I think I will make that a separate thread. As for now I am supposed to get the temp sensor I'm tomorrow, and in the meantime, I will clean up this soldering mess. I am going to put shrink wrap on the ends of the cruise control wires and everywhere else that I re soldered.

harveyf

You can get the wiring harness from the 9 pin plug into the rest of the engine bay, in particular the injectors, from the "usuals". I might suggest you bite the bullet in that regard.

Acantor

Here is my progress. I put some heat shrink on the small cruse control wires just to be safe aswell.

T&T Racing

Hi Acantor,
Wiring re-splicing looks good and clean. I believe the no start issue is resolved.
Tom

Acantor

@T&T Racing @orig944 I just put the new sensor in. It won't run. I unplugged it, and it took a couple tries but eventually it started. I tested the sensor and it is reading like 1 ohm. Did they send me a bad sensor? I unplugged it and tried it again, and it wont fire but had fuel pressure.

Acantor

does it need to be wet or something? I am very confused and a little ticked if the sensor is bad.

T&T Racing

Acantor,
Below are the resistance readings, I would test the sensor by placing one probe on ground on the engine and then use the other probe to measure each contact of temp sensor to ground to see what is the resistance to ground for each contact.


Procedure

1.  
   • Turn the ignition switch OFF.
   • Disconnect the DME computer electrical connector.
   • Connect an ohmmeter between terminal 13 on the disconnected DME plug and ground.
   • Check for the following resistances:
     
     NOTE
     The next part of the DME temperature sensor testing assumes that the temperature gauge on the dash is working properly.
     
     
     
   • Connect the DME plug connector.
   • Start the car and run until the temperature gauge on the dash indicates approximately 80 °C (see dash temperature gauge section). If you suspect that the dash gauge is not working properly, you can check the surface temperature on the block near the DME temperature sensor.
   • Turn the engine OFF.
   • Disconnect the DME computer plug and connect ohmmeter as described in Step 3.
   • Turn the ignition switch back ON (Do Not Attempt to Start Car) and check dash indication is still reading 80 °C. Alternatively, check the surface temperature on the block near the DME temperature sensor. Compare resistance to the value in the table below.
     
   • If the resistances don't meet the tolerances listed, the DME Temperature sensor should be replaced. If the resistances indicate higher than the specs, it will cause a richer mixture. Lower resistances than the specs will result in a lean mixture.

T&T Racing

This is the Bosch part number

• 0280130026

This is the Porsche part number
94460612500

harveyf

The DME temp sensor (the one with the blue plug as shown in your photo), with the plug removed, has 2 small flat blade pins. Put your two ohmeter leads on each pin to measure the resistance of the sensor. This should give you something close to the reference values quoted above so in the range 1000 to 3000 ohms (1-3 kohms). Now hook it up and check at the DME plug in the cockpit under the dash. It feeds pin 13. Checking resistance from pin 13 to a known ground should also give you the same resistance values. You can also check the sensor you just took out. It is called a Temp II sensor because its resistance increases as the temperature of the device goes down. There is a Temp I, where the resistance increases with temperture.

The sensor does not need to be grounded or wet.
BTW, the generic blue plugs that terminate a lot of your wiring harness connections are call Amp Junior connectors. They come in 2, 3, 4, etc pin configurations. They are common on European cars which means you can probably obtain bucket fulls of them at your local pick and pull. The ones on the 944 are a PIA because of the wire clip that must be prized away with a small tool. The clips tend to go missing. The better ones on later cars have a clip that releases when you squeeze them with your fingers.

There is another sensor, which is nearby, that runs the temp gauge on the dash. It has a single male blade terminal and it is grounded by its threaded fittings in the block. It has a single wire going to it with a female blade end.

Acantor

Ok so in the picture I sent, it again should not read 0 even from terminal to terminal. And from the dme with it plugged in, it should read the same right.

harveyf

Yes.
Maybe an issue. Some meters are wierd. I see you have it on the 2K range. And the meter is showing 00.2. That "may" mean 0.2 of 2K, I don't know or something like that. If you just hold the two leads together, that is what zero looks like on your meter. You might want to compare notes with someone with another meter and make sure you are reading the meter correctly.
And yes, the bottom line is that you need to read a reasonable resistance value at terminal 13 on the DME plug, which is what the DME brain will see and use as part of its algorithm.

orig944

The on/off switch at the top of your meter appears to be in the wrong position.