924Board.org

brian19600 · Joined: 28 Oct 2013 Posts: 375 Location: NJ/CT

Paul, I may be saying the same thing you are, but isn't there 2 wires that go to the starter solenoid (like a 12 ga and a 16 ga- not the battery cable)? If you get them backwards, you will have a no crank condition? And the connection of them seemed counter-intuitive....the thicker wire went to the smaller terminal or had a smaller screw. I remember thinking that they look like they should be reversed, but I paid close attention when taking them off after reading about all the problems people have.
_________________
78 924

j03k64 · Joined: 26 Jul 2010 Posts: 123 Location: Urbana, Ohio

Fusible link, no wonder I cannot find an ignition resistor anywhere.
I've never seen this referred to in my collection of manuals!

I haven't fundamentally changed anything in the wiring/setup since it started and then failed to start thereafter.

All the wires on starter are connected properly. The harness will not let you connect the solenoid wires incorrectly as the screws/eyelets are different sizes. I took it apart again to check and also tried swapping them, using bypass wiring; no result. I'll take a photo of it so you guys can have a look.

(Edited to maintain continuity of the thread)
_________________
1979 Porsche 924
1980 Porsche 924

Paul · Posted: Wed Sep 21, 2016 3:24 am Post subject:

Using great care with the car verified in neutral and the parking brake on hard use a remote starter to make sure the solenoid, starter, positive battery cable and ground are all good. If you don't have a remote starter a cable from the positive battery wire connection on the solenoid to the red black wire terminal will do the same.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Wed Sep 21, 2016 3:32 am Post subject:

In regards to the fusible link, the 1980 wiring diagram shows a 15 ohm fusible link at the end of the black wire circuit.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Wed Sep 21, 2016 3:41 am Post subject:

To test the red black wire attach a 12 V test light at the end of the wire at the starter and ground the other side of the test light to a good ground. Turn ignition key to the start position,lamp should light. A voltmeter is not good enough for this test.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

j03k64 · Joined: 26 Jul 2010 Posts: 123 Location: Urbana, Ohio

Thanks Paul!

(Post text removed to avoid confusing readers of this thread due to my own negligence; see following post)

Photos of the ignition switch wiring and T3 connector retained for reference.

T3 Connector (located outside of battery box)

Ignition Switch Wiring

_________________
1979 Porsche 924
1980 Porsche 924

Paul · Posted: Thu Sep 22, 2016 1:59 am Post subject:

The R/B has no fusible link. Check terminals A10 and E17 on your fuse box.

At T3, the smaller R/B feeds the cold start fuel injector and GN/WT feeds the cold start thermo switch.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

j03k64 · Joined: 26 Jul 2010 Posts: 123 Location: Urbana, Ohio

Apologies for the confusion. Bad week apparently

Thanks for being patient.

- Red/Black is just a big wire; disconnected or fried somewhere.
- Black is fusible, assuming near the starter(?), and in good order as tested.

Is there a schematic/photo of the backside of the fuse box with the terminal information? I've had the fuse board hanging a few times for maintenance/repair. I suppose it's possible that the wire has been dislodged as a result.

I tested both wires this evening using a 12v test light and a voltmeter at the starter. Red/Black wire has 0v going to it. Black wire has 6v going to it. Obviously, neither result will tripped the 12v test light. I'm assuming the combined voltage when you close the key trips the starter solenoid?
_________________
1979 Porsche 924
1980 Porsche 924

Paul · Posted: Thu Sep 22, 2016 10:28 am Post subject:

The back of the fuse box has sockets labeled A to F. 6 wiring connectors plug into these. You need to check pin 10 on A and pin 17 on E.

The R/B wire itself is probably OK.

The ignition switch R/B is connected to E17, the starter to A10. They are connected internally in the fuse box.

The black wire is connected to the ignition coil. Since it has a 15 ohm resistor built into its path to the coil it will read something less than battery voltage when the ignition switch is in the run or start positions. It has nothing to do with activating the solenoid.

I suggest you take a hard look at the back of the fuse box and make sure all connections are connected and tight before doing anything else.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

j03k64 · Joined: 26 Jul 2010 Posts: 123 Location: Urbana, Ohio

I pulled the fuse box wiring loom as far forward as possible today and stuck my head in there - found all the missing numbers Paul!

I found that E-connector was pulling out of position, slightly odd as I checked to make sure those were all secure before starting the car for the first time. I pulled it completely out to inspect it as you recommended. E17 seems to be in good order. I rolled it over in my hand... it looks like the maniac who owned the car before me attempted to literally cut E2 pin out of the connector using a Dremel!?

That's the black wire that runs from E2, to ignition switch 15, to the cluster gauge, to the tachometer and then to track VI-11 (Coil or ICU?). I tried to tidy it up the best I could and ensure that it went on the pin correctly. I'm assuming that's why it's pushing out of the fuse box. Formal repair is going to be needed...

A-connector is in good order on inspection.

R/B wire checks out:
Tested the R/B wire from A10 to the T3 connector.
Tested the R/B wire from the E17 to ignition switch connector.
Tested the points the plug into on the relay board.
All registered as complete circuits.

Carefully put the fuse board on the bracket. Connected the wires to the starter - you can't put them on wrong due to the size of the OEM eyelets and bolts.

It cranks now, but intermittently... 70% of the time it cranks, 30% it does not.
I also noticed some odd electrical sounds from the engine bay, while cranking. Not entirely sure where it is coming from.

Attempted to start it; resulted in flooding. I thought weak spark might be to blame, bright lemon yellow on test, the plug slid away from the ground while cranking according to the observer. Too much fuel flow is also possible. Figuring out a fix for the wiring first is probably a good idea.

Could a weak connection at E2 result in intermittent starting and or weak spark?

E-connector

Starter Wiring

_________________
1979 Porsche 924
1980 Porsche 924

Paul · Posted: Fri Sep 23, 2016 11:02 am Post subject:

E2 is a very important connection. That terminal powers most things that need power when the car is running.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

nickthompson · Joined: 26 Mar 2013 Posts: 873 Location: Central Georgia

My car won't turn over with the key either. I've got so much to do on my car I haven't even started to try and figure it out.

j03k64 · Joined: 26 Jul 2010 Posts: 123 Location: Urbana, Ohio

Seems to be the season for no crank issues after skimming recent posts!

Heading out to the shop to try to fix E2 this afternoon. I think the E2 female connector is pushing back in the E fuse block connector due to the damage, causing a very poor connection as the pin and connector would barely be touching one another; causing intermittent cranking, bad spark, and so on...

I'll pull the other fuse block connectors for inspection to make sure they haven't been tampered with. I saw C is linked in the wiring diagram to A block, hope he hasn't gotten to that as well.

I'm going to try to remove the E2 pin and wire, put a new female connector on it, hollow out the damaged area in the pigtail, plug E2 in and then try to get E connector plugged back in securely. I figure the less cutting and splicing, the better.

If that doesn't work I guess I'll have to somehow find a new pig tail and replace the wires one by one to repair the damage...
_________________
1979 Porsche 924
1980 Porsche 924

Chaos · Joined: 07 Nov 2005 Posts: 289 Location: Newark, DE, US

Yup. Must be the season for it. Add mine to that list, as well...

_________________
'81 US 931 "Rochelle"

Paul · Posted: Fri Sep 30, 2016 10:43 am Post subject:

E2 is the ignition circuit, not the starter circuit. E2 will definitely cause running/starting/flooding issues, but it will not keep the starter from cranking.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.