82 928 mpg help

[spooledx2]

LOL 10-4 Captain, will do. Thanks for the slap and the info.

Ramon

[JK McDonald]

Hey Ramon, As several others have already mentioned, one of the electrical circuits to verify when troubleshooting a 928 performance issue is the overall condition of the green wire and both connections between the ignition unit and the distributor pick-up coil.

Although this shielded pulsed signal can definitely cause all sorts of symptoms - other than being a sleeved and shielded wire, I don't think that the inner conductor is made up of a special type of material.

In the troubleshooting portion of our manual for the early cars, the open loop resistance of the distributor pick-up coil when the circuit is checked from the ignition unit plug (pin 7 and 31d) is 485 - 700 ohms. This takes into account the resistance of the wiring, the 2 pin plug at the distributor and the pick-up coil itself. The resistance spec’s given for the pick-up coil is also 485 - 700 ohms.

What is the opinion of the other members, could the green wire be replaced using a high quality shielded wire of the correct length and gauge ? If the 2 pin distributor plug for the pick-up coil could be reused (or located) and the removable pins at the ignition unit plug are re-soldered, could this be an option ?

I have made up a similar shielded cable for other cars that seemed to work OK - but they were simply soldered to a series of base terminals at each end.

Michael

[spooledx2]

Ok... so I want out and looked at my 1980 parts car. Luckily The green wire was in great condition, both connectors and the wire wasn't cracked and still very pliable. So I swapped it out and check the cap and rotor at the same time(still waiting on the new one). Everything looked good. I fired it back up and no change. Still blowing black smoke..... Tonight I will start checking the resistors and the pick up coil to see what they are reading. I will check the old coil versus the new one as well before I swap it out.

Thanks again for the help and info.
Ramon

[lfausty]

What About ? never researched this much more , cause grn wire still good,lol.,
two new white connectors for each end of greenwire, and the flat spaded ends to insert into connector. and this (pic) wire i forget what it is used for, speakerwire? >>>>>>> ?????? would it have enough resistance to use it, would hold up to heat, how to make connection with the wire in wire.

[lfausty]

couple more pics

[Anthony10370]

That's coaxial, cable TV or CC TV wire. In terms of electrical continuity and shielding It would work. I have no idea about the heat range.

I wouldn't use it because the inner wire is a solid wire and it will fatigue and break with the engine vibration and leave you stranded.

You could possibly use something like a high quality, heavy gauge, audio wire, but make sure it's stranded.

[JK McDonald]

A while back I had helped resolve what was thought to be a fuel injection problem on an old 280Z. Nissan uses the identical Bosch pulsed injector system as the early Porsche. It turned out to be a poor distributor pick-up connection at a small terminal block under the hood. Their distributor pick-up wiring is a simple unshielded two wire circuit that runs right along side the coil before heading to the ignition unit back inside the passenger compartment.

Just to test how sensitive the 928 ignition unit was to EMF pulses I built a couple of temporary Green Wire alternatives. 1st - I used an unshielded two wire combination out of a pair of 22 gauge wires from my junk parts bin and a set of pins - filed to fit- from an old harness . Miss Purdy (84 U.S. Model) fired right up. Next I used a piece of automotive shielded twin conductor speaker wire. I grounded the outer shielding (one end only per electrical spec’s). Both times, she fired right up and didn’t skip a beat even when I blipped the throttle up toward the red line.

Personally, I think the coaxial or triaxial wiring would be the best option.

Good Luck, Michael

[lfausty]

best option? would be not 130.00 make em and sell for 40.00 bucks. haha shipped!!!!

[Fogey1]

Originally Posted by JK McDonald

... Just to test how sensitive the 928 ignition unit was to EMF pulses I built a couple of temporary Green Wire alternatives. ...

Thanx, Michael,

I love the idea of ROLLING MY OWN. Did you or has anybody ever found a source for the connectors?

will