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-   -   Found a short circuit (https://rennlist.com/forums/928-forum/876789-found-a-short-circuit.html)

Tommyd928 06-02-2015 03:40 PM

Found a short circuit
 
1 Attachment(s)
Hi gang,

Can someone tell me what this circuit pertains to? I found a short circuit with several burnt wires leading from the connector on the fuse panel that says "K".

I'm going to follow the loom where it connects to, but would like to know what part of the electrical system it belongs to and how to find it on the electrical flow chart to determine what else it might have damaged!

Any information will help.:surr:
Thx,
Tom

Tommyd928 06-02-2015 03:45 PM

Picture of connector
 
1 Attachment(s)
Picture of connector and fried wires...

jwyatt8171 06-02-2015 04:02 PM

I will save the other guys some time. What year model. can you tell what terminal it went to on K?

jwyatt8171 06-02-2015 04:06 PM

https://cimg8.ibsrv.net/gimg/rennlis...b235044222.jpg

Looks like the wire pointed to here is damaged as well.
could those have shorted against that wire?

Kiln_Red 06-02-2015 04:09 PM

Ah, sorry. I see it now in your signature.

Looks like it corresponds to at least relay X which is simply badged as 'Supply.' I believe that it is for your headlights, but I am not 100% as I'm not as familiar to your CE panel.

Kiln_Red 06-02-2015 04:25 PM

You can download your complete wiring at ligeti.com/928

jwyatt8171 06-02-2015 04:39 PM

The OP does not have a signature that i can see. That may be mine your looking at.

Tommyd928 06-02-2015 04:40 PM

Guess you know, it's an '82 928S.

Well the headlights aren't working but the car isn't starting either. I was thinking it led to the ignition switch and could find something there.

Thanks for the replies.

How do I find the connectors on the wiring diagram?

Tom

jwyatt8171 06-02-2015 04:42 PM

On MY90 in the diagram the connectors are near the back of the prints.

EDIT. Big difference. I just looked at an 84 wiring diagram.

Kiln_Red 06-02-2015 05:03 PM

Looks like the ground (terminal 87) to relay VI (window regulator) is distributed through plug K. Also, the power feed to relay IX (kickdown) follows through plug K.

Kiln_Red 06-02-2015 06:04 PM

As for the no-start, do you hear the fuel pump running? If not, will it run with a jump wire in place of the fuel pump relay? Bridge terminal 30 to terminal 87. Does it run? If so, replace the relay with a new one. It's a special relay.

Once fuel delivery is established, try to start it on starting fluid. Does it ignite off of the starting fluid? If not, then you likely have an issue with the ignition.

If yes, you may have a problem with the injector circuit (likely the AFC Relay) or the injectors may not be opening despite their signal from the ECU because they are stopped up by aged fuel. Choose an injector and check it with a noid light to see if their is a pulse. If not, check the AFC relay terminal 30 for battery voltage. If there isn't battery voltage here, then you may have a connection issue at the small red wire at the positive battery terminal, a ground issue, or an issue with the ignition switch. If you have 12V at terminal 30, then replace the relay. Now go to plug X and check for battery voltage at X2, X3, X4, and X5 all with the key ON. If you have 12V here, then you have eliminated a fault with the relay and ignition switch and you should absolutely have an injector pulse unless their is a wiring or ground issue or a problem with the ECU itself (rare).

Tommyd928 06-02-2015 06:28 PM

Wow, kiln_red, thanks for the troubleshooting sequence, that is so helpful.

I need to take out the dash to get to the loom where the wires are fried. I was going to take it out any way to have it recovered (doing the upholstery next).

I'll post some more pics tomorrow.

Thx to all for your replies,
Tom

Tommyd928 06-02-2015 06:30 PM

Jwyatt,

Maybe the short did start there...good observation.

Kiln_Red 06-02-2015 06:46 PM

Hold the phone..

I didn't notice the all important letter "S" in your car details. If it's an '82 928S, then it must be a Euro spec car with the earlier K-jet system; not L-jet as my suggestions were intended for.

Ducman82 06-02-2015 07:03 PM

i thought 82S cars were L-jet, 81 "S" were K-jet i know that. mine is a 81 Competition (S without the S) before they added the S... LOL


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