Long story short, about a week ago we purchased a '79 928 that was running like dream and appeared to only need a little cosmetic work (mostly a good cleaning) A few days after getting it home, we awoke to a car that refused to start. After many suggestions from other 928 owners, and racking our brains and begging the car for answers, I think we have the problem solved. The scenario was this: seemed to be a fuel system problem as we had spark and the car seemed to be starving for fuel. Nope. I was determined it was the timing, checked that last night. Nope. It would fire with ether (I know, not a good thing to do) and would also fire (sometimes) if we advanced the distributor. The alarm was going off all by itself (usually while someone had their head under the hood!) so we thought maybe it was the kill. Nope. Turns out, through some pretty impressive deductive thinking, my SO figured out that it wasn't actually advancing the timing that was starting the car, he was moving something else in the process! There is a fairly heavy guage green wire running into the distributor. Apparently, this was our problem. After 'wiggling' this little demon the car is starting like a dream!

My question is this: Is this little green wire a power feed of some sort? We're still waiting for the manual to get here so I can't look it up yet. My hunch is it's corroded inside the distributor and/or causing a short. (the battery mysteriously died over the weekend too). This will be some investigative work for the weekend. Was just curious if someone could give us a leg up on this so we know what we're dealing with.

Thanks!

 

Ha, congratulations on your find. I have been hunting for a problem for two and a half weeks. My 79 would be running perfect and while driving just start running horrible and die. Then it wouldnt start. And then after moving stuff around in the engine compartment it would start up again, run fine and then run bad and die again. I traced everything fuel, ignition everything. Then I ran across the green distributor wire which everyone says it doesnt go bad often. This wire is a sheilded wire. Well the one end near the ignition control unit was hard and brittle and started breaking apart. The inner part of the wire would ground on the shielded part of the wire. when this happens the car will die. What the green wire does is comunicate from the distributor to the ignition control unit telling it when to fire the coil. If you have no signal the car wont start, if you have a poor signal the car will run like crap. You might want to check and make sure its connected okay inside the distributor. You should remove the wire and check with an ohm meter. make sure you move the wire, twist it and whatever to see if it shorts on itself. Maybe you just have a corroded connector inside the distributor or the other end that you can simple clean up a bit. But remember that this is an important part of your car.

I just bought mine just the other day from 928 international from Jim. (714-632-9288) Tell him I sent you his way. The price has shot up on that little baby. It was 40 bucks now with shipping it came up to be like 72 bucks. I have not installed the green wire yet but I am positive that this will be the cause of all my trouble.

Please let me know if you have other problems with your 79. I have been through just about everything with mine. Including checking my entire fuel delivery system to make sure it was within spec. I had to make just a few adjustments to it but nothing serious.

Do all your instruments work in your dash pod?? I have been through mine and could help out a bit.

Good luck!

 

Thanks a bunch Curt! Funny how things work, we were ready to rip into the fuel system until we found the distributor wire. Seems to me in order to trouble shoot these things we're going to have to think more electrical than mechanical. Not my forte!! The instruments seem to be working fine for the moment, but I'll let you know if we run into anything there. We are having a hard time figuring out the a/c fan. It ran momentarily but again, mysteriously died. The power seat on the passenger side is possessed also, moves forward all by itself. I picked up a new wiring harness the other day hoping that will solve that problem.
Thanks again for your help!

Anne

 

Anne, welcome to the workd of 928 ownership! You've had a baptism by one of the most notorious demons under the hood. Good job on findig that one by yourselves!

Curt, have you ever hear of anyone using a standard co-axial shielded cable to replace the green wire? It seems like any shielded wire would do the job. Any comments from anyone else on this? My GW is fine (for now...) Just wondering if it could be done.- Ruf

 

I also may have problems with my green wire. Have all but exhausted all routes with the fuel system and am now looking to ignition components.

Would also be interested to see if anyone has replaced with a piece of co-ax.

 

Anne the green wire also used on many 911 cars is notorious for failing and causing strange running problems . One very good repair shop I know refuses to work on cars with obviously old green wires too many issues too much lost time when it starts to break down . The seat moving by it's self is probably the extra switch on the back rest which when you tilt it forward as though you intended to get into the rear it moves forward to ease access to the rear seat .

 

Im not sure about the co-ax, you would have to make your own ends which might be kinda difficult. I bit the bullet and just bought a new one that will last the rest of its life.

Sean what kind of problems are you having?

Anne, luckily I dont have power seats. Thats one less problem. Oh, and the A/C fan should come on when you turn on the A/C, also, with the A/C off and when im sitting in traffic when its how outside, the temp of the car comes up and at a certain point the A/C fan will kick on and cool down the motor. Once the temp drops the A/C fan kicks back off. You might want to check your fuse panel to see if it has blown the fuse. Mine has a few times. Also, if you havent already changed out all the old fuses its a good idea to buy new and replace all of them per your manual. When I got my car all the fuses were old and wrong sizes had been put in.

 

Anne - welcome aboard. Being that your in my kneck of the woods, you should come out to the next PCA event and meet the Rest of the 928 gang. There aren't too many of us but like the marines.

The Few...the proud ...you get my drift.

Richard A. is the local 928 Guru. He owns three sharks, in fact one is a sweet track car. The man KNOWS 928's.

I have recently becomed involved with the PCA although I do most of track racing/course officiating with Professional Auto Sport.

Drop me a line if you would like, yourself and your SO are moe then welcome to come out and see what it's all about!.

Kudos to you both! <img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" />

 

Thanks for the help guys. We're going to tear into the distributor problem this weekend, along with the seat and the a/c. I'll let you know how it all turns out

Drew, we checked out the PCA and PASA websites and they look great. We'll try to get out this weekend if the shark doesn't keep us tied up

 

Curt, my problem is hesitation which occurs when hot at low speeds with no apparent pattern. I have replaced :

plugs / wires / rotor / ballast resistors / coil / ignition control unit / checked timing.

injector bushings / spyder rubber tubes & gaskets / all vacuum hoses & tees/ removed EGR / throttle o-ring & rubber tube / gasket between air flow meter & lower plenum.

WUR / fuel filter / cleaned in tank fuel pump screen / checked control & pump pressures/ jumpered fuel pump relay / gallons of Techron.

I have the two fuel pumps on order from Devek and am hoping that maybe there has been an intermitant fault with one or other pump.

The above posts about the green wire could be another possibility