no spark / no start
 

I backed the 928 into the garage at the end of October so I could work on it over the winter. It was running at the time. I tried starting it today, but it appears that I’m not getting any spark. It cranks but won’t fire, not at all. While my wife was cranking the engine, I put the test light to the leads on the coil, the spark plug wire running from the dist. cap to the coil, the green ignition wire itself, and then elec. connector on the WUR; nothing.
I replaced A LOT of stuff over the past few months, but the things that would affect the engine are as follows:

1) All vacuum hoses under the hood were replaced.

2) I replaced the front and rear cam seals. In putting the front seals on, I had to pull the distributor out of the block. Before I did this, I put marks on it and the cap so everything would line back up to be the same as when I took it and the cap off. When done with the front seals I made sure the engine was at O/T (0°) and the cam gears were line up correctly when re-installing the timing belt. I checked it again today and everything still lines up.

3) I replaced all of the following wiring connectors with new pigtailed ones from Napa: start valve (which connects to the front of the spider), aux. air valve, and WUR. I think the original colors of the connectors were black, blue, and brown.
I thought about replacing the cold start valve elec. connector too, but couldn’t find a suitable replacement. I just cleaned the contacts on the cold start valve and then plugged the connector back on.
I soldered all joints and put shrink wrap over them.

4) I replaced the rubber fuel lines in the engine compartment with replacements from Roger. (I can’t put the new rear hoses on until I get the car turned around in the garage).

5) I put a new alternator on and the two elec. connections are tight.

6) I opened up the WUR to check the screen (didn’t see one). I made sure the little spring went back in the way it came out.

**7) The infamous green wire was spliced when I got the car, but it ran fine. I undid the old splice and attached the two ends of the green wire with one of those tube-shaped elec. connectors. I cut the plastic cover off of it, pinched both ends of it down good onto the bare ends of the wire, and then dripped solder into a small hole in the middle of the tube-shaped connector. I have not shrink wrapped it yet.


Here’s the data I have gathered so far:

a) I have fuel at the fuel solenoid valve (passenger side, top of block) and WUR. I loosened the fittings in both places and fuel started to dribble out.

b) The test light did not come one when both ends of the splice of the green wire were touched.

c) I checked all of the fuses and only the fog light one was blown. The start bridge relay is also good.

d) I tested the temp. switch on top of the water bridge / thermostat with the test light while my wife cranked the engine and there was no light.

I could really use some help here guys. I need to get might 928 back on the road. I’m going through withdraws!

get a new green wire and connect it correctly

But shouldn't there be power running from the CE panel to the green wire? Shouldn't the test light come on when touched to the green wire at a point before the splice? It would make sense to me if the splice was where the problem is at, meaning there would be no power on the section of green wire AFTER the splice.

When I did my timing belt and cam seals, just moving the distrb around caused the connector for the green wire (the side away from the distrb) to crumble.

I would replace the green line even if the car was running. You do not want it to strand you somewhere.

Okay, just ordered a new green wire from Roger. I'm still confused about not having power to the current green wire though. The splice is right around where the 14 pin connector is located. To me, it seems that there should be current flowing in the section of wire running from the CE panel up to the splice. But when I put the test light on that side of the splice, I get nothing.

Do you have power at the connector itself? If not, then the problem is still upstream of the green wire.

crank position sensor?

I can't test at the connector because there is not one. That's where the splice is. The PO removed it, for some reason, and then spliced the green wire section coming out of the loom on the passenger fender to the green wire section coming from the distributor. I ordered a connector from Roger too.
I too am wondering if there is a problem upstream since the test light doesn't shine when placed on either side of the splice.

Yep, it was the green wire. It wants to start now, but idles only for a second or two before stalling. Then it backfired out the top of the block. That makes me think I knocked the timing off when I pulled the distributor. I need to go back to the WSM now and read up on how to adjust it.

Cool, deal. Yeah, I just replaced mine rather than tinker with it since it's a known problem with starting issues.

Ah, for the days when you could run a hot wire to the coil....

what green wire
 

i have a similar problem when i turn the key the engine cranks but my dad says that its not getting spark i want to check if its this green wire problem but i dont know where the green wire is can anyone help me find it

Here's my write-up with pics.

Porsche 928 Forums dot com - View topic - Pics of my First 928 and Current Project

thx i looked for it earlier and i found it im gonna try to just clean up the contacts and see how that works