SB928

Hi Guys
Asking for help diagnosing a no start problem on a '79 RoW/Euro Auto that I bought several years ago and am finally getting around to get it running again.
Actually I'm not worried about starting it right now as much as I'm just trying to get a couple of electrical bugs worked out, namely getting the key/ignition switch to actually turn over the starter, and for the headlights to come on when they are raised.
Without boring you guys with the whole history of the car, I will say that a couple of years ago I had basically everything working. Key would bump the starter, and engine would start, and headlights would raise and light. Then it sat for a few years. So, of course, i started with the grounds and replaced the battery neg. cable. Again, I think every light and switch works with the exception of the starter by the ignition switch, and the headlights by the headlight switch.

The engine is currently undergoing a FD/WUR rebuild by Larry at CISFlowtech as well as replacing/rebuilding the engine wiring harness. Found an almost new harness on eBay for $75 that I only needed to add the electrical 2-pole fitting for the WUR as it did not have that fitting. The old harness was completely shot.

As both of these problems are electrical, after numerous searches, I have done and confirmed the following:

battery is a few months old and has a full charge (12.7v).

pulled the 14pin top connector and bumped the starter by touching the large
yellow wired pin (forgot the # as I'm typing) and starter did bump.
(that alone did a lot in confirming battery/wiring/starter/14pin OK, right?)
Just still wondering about the starter solenoid, though.

Next, after reading a thread here about jumping the starter relay block at pins #30 and #87, I got the ignition switch to bump the starter, great, but now what?
What does jumping those two wires do and how close am I to getting the key to work the starter?

As far as the headlights, I have confirmed the wires to the headlights are not broken and they work, as I put a battery on the fuses at the CE panel and both lights do work. Headlight switch? Anything I can test although the reason I'm here is I'm better at house wiring/electrical than car, but I've done pretty good up until now.

Any help/observations greatly appreciated.
Bob

Kiwi'79

Gday and Welcome!!

Unfortunately I am a noob, therefore, not qualified to fix your problem, the gurus will get back to you soon.

Meanwhile did you happen on this one (below) a few days ago? great stuff in there.

https://rennlist.com/forums/928-foru...art-issue.html

Anyway please DO bore us with the history!!! We love this stuff especially the OB clan.

Oh and pictures please!!!!!

SB928

GDay Kiwi, Thanks for the response. Still narrowing my problem down to wiring between the bottom half of the 14 pin connector to the CE panel. I'm 90% sure it's not the ignition switch as I can hear the starter relay click when it's turned, plus I get voltage at the #15 starter relay.
The strangest part about all this is that they both worked no problem a couple of years ago and nothing was done to anything. I keep wondering if there are still remnants of a security system I torn out when I bought the car, but i had it running after I did that also.
I've cut open in several areas the wiring harness on the passenger side fender like I said from the female side of the 14 pin connector to the firewall above the CE panel and find no areas that look overheated or damaged, but I know I'll probably have to inspect EVERY wire. Probably would be smart to get one of those electrical tools that puts a tone in the wire to be able to trace the wire and check for continuity.
I was hoping this issue, along with my headlight issue, was familiar to someone here and could help point me in some direction before I start destroying wiring harnesses.
Thanks again
Bob

SB928

What does NOT having voltage on the female side of the 14 pin connector at pin #14 (large yellow wire) mean ? I know i have voltage at the jump post and I can bump the starter by touching the #14 pin to the jump post.
I'm thinking there is a burnt/broken wire between the connector and the ignition switch, or the CE panel.

The starter will NOT bump by the ignition switch.
From the female side of the 14 pin, where does the power go? to the CE panel or to the ignition switch and gauges, etc.?
Thanks
Bob

dr bob

First, welcome to the group!

-- You'll benefit greatly by getting a copy of the workshop manuals including the wiring diagrams. Electrical troubleshooting without them is frustrating and can be expensive. There are links in the "new visitors" thread at the top. One of our vendors, 928SRUS, offers a CD set that includes an indexed and linked workshop manual set as PDF, plus a slew of technical pubs and articles that will help you support the car. Worth the money IMO.

The starter circuit in auto transmission cars includes a neutral safety switch intended to disable the starter circuit unless the gearbox is in "neutral" or "park" positions. There's a "starter blocking relay" in position XV that has a coil (86) connected to circuit 15 (true on "run" or "start" position) with the other side (85) routed through the neutral safety switch via CE connection U7 and on to ground. Connection 30 on that relay is connected to the ignition switch 50 (key in "start" position), out of the CE panel at O5 (that's "oh" not "zero") and on to pin 14 of the connector by the jump post. You can test for the neutral safety switch and ground with your DMM on Ohms connected to 85 in the relay socket. Should show almost-zero Ohms to ground there and at U7 with the gear selector in neutral or park. If that doesn't happen, look at the switch (side of the gearbox) and the connector in the spare tire well. Check the ground in that same area.

SB928

dr bob, Thanks for the description and advice, I think. I had to read your paragraph about 10 times S-L-O-W-L-Y to have it start to sink in and figure out what you were explaining.
I've been doing fairly well up to now with this electrical issue(s), but it seems this is getting to another level and why I came here for advice.
I've been thinking about even temporarily bypassing the large yellow #14 wire on the female side to the CE panel with a new wire since I'd rather not cut open the entire harness trying to find the break or short. But now, as you mentioned and I forgot, the neutral safety switch and if bypassing would affect its operation.

I was beginning to think I had narrowed my problem down to a bad wire from #14 pin to the CE panel since I'm not getting any reading at #14 on the female side, but now I'm not sure where the neutral safety switch comes into play here.

Have to ask, but what/where are connections/slots O5 or U7?

Thanks again,
Bob

SB928

Nevermind the last question, think I found them. They're the alphabetized female sockets at the bottom of the CE panel right?
Will just need to find out how they are numbered.
Thanks

dr bob

The connections are numbered from bottom to top, then left to right. So the bottom left connection is 1, bottom right is 11. They then number up as you move up on the connector. The early cars (like yours) have fewer rows than the later cars, but thanks to the way the pins are numbered they can use the same numbering system.

There are a few guides available on this stuff. Search for posts by RL member Alan here. He's shared some great guidance on this stuff. I've been able to decipher wiring diagram stuff well enough to generate troubleshooting steps for some of the more common issues. I used to teach this stuff in industrial (power plant and manufacturing) environments. Meanwhile, Alan's guides are more structured and may be easier to understand.

docmirror

The ignition switch is also a high failure item. If you check the voltages at the connector to the ign switch, and find that the power is coming in, but still no start with the key, it may be faulty ign switch.

SB928

Again, Thanks to the two Dr.'s for responses.
dr bob, checked for ohms at #85, nothing and at U7, there seemed to be a fluctuating reading. Will have to check that again. One question though, do I take these readings with the ignition switch on or off?

docmirror, yeah, at first, I was leaning towards the ignition switch, but I can hear the starter relay click when it's turned, and when I jumped the starter relay #30 and #87 pins, I got the starter to bump with the switch. Should be good, right?

Right now I'm trying to find the neutral safety switch on the side of the transmission, need to get the CD's dr bob mentioned.

Thanks guys

Bob