ok, i have an s4 na and it has burnt wires inside the car... at least from what i can see. The engine and dash is out and now i just have to fix the problem, i have a parts car to get whatever i need from...

problem is , i dont really know how i would go about testing things to know if everything is all fixed without actually putting the engine in after and seeing if it starts up...how would i test the wires individually with an ohmeter/multimeter ?

the problem the car had was it was getting no power to the cas (crank angle sensor), and therefore was getting no spark/ignition. the wires in the car that appear to be fried are all on the drivers side all around the fusebox and where the drivers side door is...

i would think i wouldnt have to replace any of the wiring in the engine bay to fix this problem since i didnt see any burnt wires upon inspecting everything in the engine bay, i checked as far as to the firewall, i can see the main wiring harness looks like it goes under the car though near the transmission...so i havent really looked at that...but from what i saw all the burnt wires are in the car ... i would think there would have been burnt wires right around the cas and/or coils but there were no burnt wires to be found...

i can take pictures of the wires that were burnt if anyone would be able to tell me what they goto ?

there are several wires burnt together and such (probably like 2-5 different ones)... i have no idea what caused the short , i got the car when it was like this...but from what i saw alot of the wires were mangled with and ill be replacing anything that was tampered with

any help would be very much appreciated.... i really wish there was someone in the area that could help me out... i dont plan on takin it to a shop to get fixed and pay 1000 bucks

 

anyone ?

well i have no idea about much of the wiring on the car , all i look at is the fsm online and im not good with wiring diagrams

but from what it looks like in the car it looks like the wiring for the cas goes through the main harness on the right side of the car (driver side) and not on the passenger side but does it go into the ecu or just into the fusebox, or both ?

im doing all the work myself pretty much with just a haynes manual and looking at the fsm on here since my printer is out of ink

 

You need to get your hands on the FSM wiring schematics first, so that you can compare wiring colors & connectors to the systems they belong to, then interpret whether or not voltage should be present at the spots you want to check...

The Haynes manual sucks for wiring schematics...

Voltage checks would be preferable, as far as I'm concerned...

 

wiring was just all tampered with... there are some wires that i go from 2 to 1 and 1 to 2 and **** like that , it just makes no sense , so im working on tracing them and taking them out or clipping them and replacing with wires from my parts car , but i may have to replace the entire harness i have no idea... i just know its all around the fuse box and im assuming that goes to the ecu and engine ?

 

What do you mean by "2 to 1..."? On some important wiring runs (fuel injector wiring from the ECU comes to mind), the one wire splices into two for the run through the connectors, for reliability reasons. Is this what you're talking about?

That engine bay fuse box is the electrical "heart" of the car- it feeds everything else on the car, including the cabin fuse box (which breaks the main power branch into the sub-branches). Just grab the FSM, and follow the wiring on the car while comparing it to the schematics (wire color, destination of that particular wire, etc...). Hi-light them on the schematics as you verify proper location, termination, etc...

Continue doing this for all wiring in question...

 

its a wire on the harness that goes to the back of the car on the drivers side, right after the clip for the harness to the back, there is a wire that hastwo wires coming into it from the back , it was taped up and crimped together by whoever was messing with it

 

Sounds like a previous owner did his own wiring, in which case I may not be able to help you much. Just follow the wiring & see where it goes to see which components it feeds, etc...

 

everything before this seems to be messed (burnt / tampered with), and aside from that i know he rigged the fuel pump to some power wire somewhere not the wire its supposed to be on ... i dont know why, but ill have to fix that too

 

if you have burnt wires i would seriously consider just replacing the suspect harness, burnt wires usually lead to circuits tying themselves together(voltage bleeding from one circuit to another) and causing all kinds of nightmarish problems to arise and try and diagnose, simply using a voltmeter or ohm meter usually won't turn up definite problems with a circuit.


if you don't have spare harnesses i usually cut the insulation back from the harness in question and visually inspect the wires all the way through for cut, burns, chafing, etc. then manually check the resistance of the wires in the circuit and lastly check voltage output from the harness.

 

i agree with ^^ that guy... if it's burnt, it might be cracked, etc.
Plus, DIY wiring is generally a bad idea...
To test thow.. find the positive and negative wire for whatever you wanna test (dummy light, etc) and see if there's 12V+ across it when it's sposed to be lit up with the multimeter. If that doesn't make sense to you, might not be a bad idear to get somebody to help you. This is a BAD place to make a mistake.

 

youre talking about the foam on the firewall right ?

ihave most of the stuff out already , dash , seats, and rug, and the engine.. so i just have to get a printer to print the fsm

 

yeah i really do need someones help, i dont know shizzle about using a multimeter testing wires... all i know is that u put it on the + and - but im sure its a pain to find the + and - for the wires

if i made a mistake testing would i be frying more wires

 

I just finished "simplifying" my rear harness for my track FC. There are several places where the harness has crimped lines, notably in the chassis ground lines. The factory crimps are taped and use little folded bits of metal about 2-3mm long.

It sounds like your prev owner had either an aftermarket fuel pump at one point, or had tried to put in a fuel-cut relay.

Debugging the harness can be a real bear. Just take your time, have paper and pen handy to write down notes as you go, and use a DMM with a "continuity" setting (it will beep when it detects a connection).

Good luck,

-bill

 

they look tampered with tho, was it green tape around the spots that had the crimpeted wires ? mine has green tape around it and looks like it didnt come from the factory

there are several wires i will need to replace entirely, or the entire main harness on the driver side, i checked and it looks like its not the wires from the fusebox...but you cant really tell because it was ' modified ' to run after it was fried.... two red wires with blue dots, and one other wire (forgot color), ill try to get some pics up soon...

it sucks i dont have ink for my printer to printout the fsm , that would help me alot

 

should be getting printer cartridge later...found the mainly fried wire is a white wire with green stripe

 

upon further inspection i found there is a wire on the harness fore the main fuse box that is white with a green stripe, the retractor fuse...what is this for ?

i have to trace the burnt wire in the car and see how far it goes...but im thinking this harness is where it ends up , just that its not burnt atall in the engine bay , seems to be be burnt right around the firewall inside, so burnt that all the shielding came off...

well if this is just for the lights then it cant be my problem i know the lights worked before... but still wondering what wire(s) are causing my ignition/cas problem

 

looked at some more wires... there are wires tampered with (taped together , on the signal ecu (3 wires into one wire) and also found thre were wires on the dash harness right near the clip that must have caught some heat since they were still completely intact and not cut but the shielding was missing and covered with electrical tape ...

well i may end up having to pull all the harnesses for all i know just to solve the problem , but if i do that i might as well replace them all with harnesses that i know are good... has anyone ever done this ? i imagine its a pita but i want to have a clean nice looking car, the other car is all fine and well but its ugly and rusty/beat looking compared to the one with the wiring problem

if anyone wants to see some pics of my project just tell me , i got a digital camera... i probably will take pics sometime soon when ive advanced in my progress


one other question ? could having your timing so far off create no power to the cas/ no ignition at all .. or would it just be misfiring ?

when i bought the car hoped it was just abad cas but i guess it turns out to be alot worse than that ! oh well at least i have a nice clean cas to put on my rebuilt engine

 

In answer to your earlier question, I believe that the bright green taped areas are that way from the factory. Some of the factory splices, while perfectly functional and reliable, aren't the best looking things in the world :-)

My S5 FC project is a completely stripped shell, so the only harnesses in it right now are the ones in the doors. I was going to try and get the front and rear harnesses reinstalled yesterday, but the weather wasn't cooperating <:-(

If your main(front) harness is really butchered, then replacement may be your best choice. Repair isn't difficult work, but it is long and tedious.

(hmm, come to think about it, I may have a spare S4 front harness around somewhere, but I'll have to check)

Good luck,

-bill