Interior wires and ECU...

#1

I appreciate your reply’s and expertise!

Been gutting interior harness’ and wires like… central locking, mirrors, stereo, windows, lights, etc.

I unpluged and cut away the 3-wire pig tail from the ECU(yellow 380) I know STUPID!!! The wire colors and pin identifications are Blk/Blu(#6)-Output RPM, Grn(#27)-Input Ignition & Wht(#32)-Fuel Rate Out. It seems to me the critical one (full race) is Ignition input Grn, as the car won’t start. Is this correct and do the other two need connected??? I can’t recall where I cut the green from, can it just be tapped into a green “switched” wire? Any recommendations where to tap???

Also, above the steering columm attached to the body/firewall is a “relay” What is that for? is it needed?

One more… is there any use for the yellow plug-in in the cluster?

5/87 325is

Thanks!

#2

PS: In pulling the on board computor wires/harness, I also took out the plastic black box mounted at the firewall driver left, realoem says its the on board computor relay. Looks like the green ignition input wire from the ECO (3-prung) leads to that? Do I need to put that back in to run?

THANKS!!!

#3

[quote=“NASA144” post=71446]I appreciate your reply’s and expertise!

Been gutting interior harness’ and wires like… central locking, mirrors, stereo, windows, lights, etc.

I unpluged and cut away the 3-wire pig tail from the ECU(yellow 380) I know STUPID!!! The wire colors and pin identifications are Blk/Blu(#6)-Output RPM, Grn(#27)-Input Ignition & Wht(#32)-Fuel Rate Out. It seems to me the critical one (full race) is Ignition input Grn, as the car won’t start. Is this correct and do the other two need connected??? I can’t recall where I cut the green from, can it just be tapped into a green “switched” wire? Any recommendations where to tap???

Also, above the steering columm attached to the body/firewall is a “relay” What is that for? is it needed?

One more… is there any use for the yellow plug-in in the cluster?

5/87 325is

Thanks![/quote]
IIRC green is always switched hot so any will do.

The ABS relay is in the area you describe. I think of it as being above driver’s left knees. They are usually metal and slightly taller than most relays.

#4

I know of the ABS relay… it’s attaches under the columm by the ignition switch. This one is tuck up back in there above the columm at the firewall/column body support.

I wired the green to green "switched and the blk & yellow-wht back to the blue cluster plug and I’ve got nothing… GRRR! No starter!

Oh boy… I think I’ve cut something bad.

List of wires I’ve cut out… from source to finish (power/grnd).
stereo
central locking
windows
fogs
brake pad sensors
sun roof
on board computor
mirrors
glove box light/flash lite
horns
exterior temp sensor
Two temp t-stat for aux fan/radiator
Ck control
Seat-belt warning?
Misc unused plug ends (under dash)

Basically trying to leave cluster (gas/tach/speedo) and defrost.

Juat thought of something… there is a switch on the clutch pedal, like the brake switch. Is it important? what does it do? I pulled the wires!

HELP ME PLEASE!!!
Thanks,
Will

#5

The Hot in Start and Run circuit from the ignition switch goes through the OBC code relay. If you removed the relay a bypass is required.

The DME must have the START signal on C104 to run and if you want the tachometer in the cluster to work the tach output signal is required.

The clutch switch only affects the cruise control.

The The Hot in Start lead doesn’t go directly to the starter. The car’s body harness has to allow for the Park & Neutral switch of an automatic transmission. If you cut any of that out you will have to find the black yellow wire under the column and splice it back in before it foes through the firewall.

#6

I think the clutch switch is only used by the cruise control.

#7

Thanks Turbo…

Jim,
To “bypass” the relay, just run a green lead directly into the ECU switched input pigtail? Or do you recommend leaving the relay?

Thanks,
Will

Ps: I’ll check out the blk/yellow wire soon… I’m sure I cut them, Damn!

#8

[quote=“NASA144” post=71462]Thanks Turbo…

Jim,
To “bypass” the relay, just run a green lead directly into the ECU switched input pigtail? Or do you recommend leaving the relay?

Thanks,
Will

Ps: I’ll check out the blk/yellow wire soon… I’m sure I cut them, Damn![/quote]
The easy fix for the code relay is to jumper the switched socket pins or splice the wires if you cut out the socket.

#9

same as… green direct?

do you know what the relay is mounted high above the column into the firewall-steering column body support?

Jim, I appreciate your help & expertise!

#10

Not off hand, and there were variations as to what got mounted where over the production life of the E30’s. Trace the wires to see where they go and use that information and the wiring diagrams to see what the relay does.

#11

“The The Hot in Start lead doesn’t go directly to the starter. The car’s body harness has to allow for the Park & Neutral switch of an automatic transmission. If you cut any of that out you will have to find the black yellow wire under the column and splice it back in before it foes through the firewall.”

Where does the blk w/yel strip wire come from and go to?

#12

As I recall it goes into a harness that goes over to the tunnel area. The back through the firewall to C101 (pin 18)qn

#13

Not off hand, and there were variations as to what got mounted where over the production life of the E30’s. Trace the wires to see where they go and use that information and the wiring diagrams to see what the relay does.[/quote]

Looks like it may be the “over voltage protection relay” is it needed?

#14

Not off hand, and there were variations as to what got mounted where over the production life of the E30’s. Trace the wires to see where they go and use that information and the wiring diagrams to see what the relay does.[/quote]

Looks like it may be the “over voltage protection relay” is it needed?[/quote]

Correction… it’s the “seatbelt warning timer” no need.

#15

As I recall it goes into a harness that goes over to the tunnel area. The back through the firewall to C101 (pin 18)qn[/quote]

Not sure I understand you on this…
There is no blk/yl wire going to the tranny.
Is C101 the main fuse box or diagnostic?

I’ve got the tach and “switched input” tied back into C104-DME :slight_smile:

#16

As I recall it goes into a harness that goes over to the tunnel area. The back through the firewall to C101 (pin 18)qn[/quote]

Not sure I understand you on this…
There is no blk/yl wire going to the tranny.
Is C101 the main fuse box or diagnostic?

I’ve got the tach and “switched input” tied back into C104-DME :)[/quote]
C101 is the round connector next to the fuse box.

If the car has a manual transmission it won’t have the Park/Neutral safety switch for the starter. But the few cars I’ve turned into Spec E30’s did have part of that harness.

#17

I got everything wired up and no start… then relized an hour later I forgot to screw C101 back together, DUH!

All good… THANK YOU!!!

#18

Another issues… fuse #10 (tach/gas/speedo-cluster) keeps blowing randomly. I quick wire trace shows nothing obvious. Is there any known issues with this? Anything specific I should look at? I bumped it up from 7.5 to 15amp and its holding, but may not be a good fix.

Thanks for your replys!

#19

Fuse 10 also powers relay K7, the reverse light switch, the Check Panel, and seat belt warning timer. Some of that may not still be in the car, but if the wiring remains there could be a short.