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Can I ask a clarifying question here - will the injectors pulse regardless of whether there is fuel in the lines or not?
That is to say, even if the system is totally dry will the injectors still pulse? I'm asking because I don't want to be chasing an electrical issue that's nonexistent because it's actually a fuel dependency. Does that make sense?
Nothing like a sick car to teach you the ins and outs of a vehicle eh?
EDIT - replacing the battery ground strap did no change anything. Nate - she fires right up on the cold start so I don't think I've got a timing issue.
I think I found it-I was going back and checking grounds and I realized I never checked to make sure that I had good continuity on this ground. This is the critical one I believe, and I currently have infinite resistance. In other words even though I have a good ground when I check my resistance using the multi meter it's always infinite. That suggests that there is a break in that grounding circuit that needs to be addressed, right?
^ Ha. I was just about to suggest you check this ground and clean it. There is a second ground just aft of that one below the diverter valve (it connects via #3, #10 washer and bolt). Make sure both are clean and the remove any oxidation on the cam cover where the ring surfaces touch. Also squirt some DeOxit in in their fastener hole. Basically clean the snot out of all the ground surfaces.
That is very good news. If you aren't getting continuity from the grounds at the connector, neither are your injectors.
Happy hunting! Have you thought about pulling the whole injector harness so you can inspect wire condition and to make sure that everything gets re-connected to something.
OK - thinking about this but not sure I have this right.
If these grounds connect into the main engine harness (022 906 239) then they will end up at the L-Jet connector to the ECU, right?
That means I am going to end up tracing them back to the L-Jet connector plug for the ECU, right?
If they are going to end up at that plug is there a reason why I can't carefully open up that protective cover, isolate the brown wires that are dead and then ground them near the fuse box? That should give me a good ground which should allow the injectors to pulse, right?
There are only four grounds here, are those the same four grounds that go to that cam cover groundi on the cam cover underneath the air valve? If so then I can pull these wires back through the harness and ground them locally and I should be good.
That one's above my pay grade. If it was that easy, though, it would seem like the factory would have saved costs of wiring runs and installation.
First of all, thanks for all of the help. I very much appreciate your and the rest of the Rennlist'ers help here.
I was wondering about that too. It seems they mainly located ground points nearby the component being grounded, but if the ground is good the resistance should be so low I am not sure that matters.
The fault in this engine harness strongly appears to be in the brown grounding wires, and I've traced them back to where the harness disappears into the firewall. Short of pull the whole thing, which is a good suggestion that I haven't lost sight if, the best option to see if this fixes it is to run a local ground. If it does then I can carefully put the harness back together and wrap it up in electrical tape (which I hate as much as the next person but I want to drive the darn thing) and call it good. If it doesn't work then I need a new engine harness anyway and I'm not much worse for having tried.
Make sense? Am I missing something? Yes/no/better way anyone?
My only thought is, if the harness is this bad, even if you rig it up to verify that it runs, the chance of it flaking out on you and causing all manner of weird behavior down the road is pretty high. By all means, do this to verify that it's the problem, but for peace of mind, a replacement harness is not a terrible idea.
Makes sense, I just want to clarify some 928 terms in case you order a new harness. People usually call the harness that runs through the 14-pin connector the engine harness. You're having trouble with your injection harness.
Of course they're NLA from Porsche either way, but some of our vendors make replacements (but not as certain about '84)
Have you done a continuity check with a multimeter on the 4 ground wires in post #83? The ones that you have disconnected and fount that 2 were broken?
If these go to pins 5, 16, 17 and 35 of the L Jet connector, that may be your problem. You will be able to check the individual wires now that they are separated.
Does the 84 wiring diagram show 4 wires going from those pins to a common ground point?
It appears from your photo that there were originally more than 2 wires at the ground point (the 'ring' connection that you have cut off)
06-20-2017, 03:35 PM
