hella24

iTrader: (8)

I have a 1986 turbo 2 with a haltech sprint re .I was driving the car and it suddenly died. I noticed the fuel pump wasn't priming when I tried to restart the car.

While looking for the problem, I discovered switched 12v supply wire to the haltech had no power. The previous owner used the black wire with blue stripe from the stock ecu f31 connector to supply switched power.

I then connected the sprint ecu switched 12v to another 12v switched supply. The fuel pump and haltech started working again.

The car still won't start.

I cannot restore power to the stock ecu f31connector black / blue stripe wire. I have checked every fuse.

Where does the Black/Blue stripe get its power from?
What does it run through that would kill a running car?

I would appreciate any suggestions you could give me . Thanks

satch

iTrader: (1)

First things first. There are two types of switched power. There are wires which have voltage w/key to on and start as well, and then there are wires which only have power w/key to on but not key to start thus if you pick the wrong wire then it can appear you have voltage w/key to on but not key to start so this would cause a problem if you are trying to power up an integral component such as an ECU.

Now if you are certain that the wire previously used is Black/Blue and not Blue/Black then the B/L wire running to F-31 runs to two components. One is the split air solenoid and the other is the over the top switch. Now the thing about these two components is the ECU is responsible for sending a voltage signal to these components meaning the ECU does not receive voltage from B/L but the other way around. W/respect to the solenoid, this item has two wires connected to it. One wire is B/W which is power from the main relay while the other wire is the Black/Blue wire running from the ECU. If the B/L wire has voltage then the solenoid turns off. If the B/L wire has a ground on it then the solenoid turns on. The over the top switch has a ground wire plus the B/L wire. W/the switch closed the ground makes its way through the switch and grounds the B/L wire which in turn turns on the split air solenoid. If the switch is open then a voltage source is applied to the B/L wire. In summary, this is not the proper wire to use at all unless both these components were overridden and the wiring to each item was altered. Even in this case the voltage on the wire comes from the ECU so it is an output wire and not an input wire. Understand?

Normally the ECU is powered by the B/W wire that would be found in pin 3I which has voltage w/key to on and start and comes from the main relay.

hella24

iTrader: (8)

Looking at the back of the connector the wires near it are ... black / red stripe , then the b/l , then g/b , then l/o.

So that wire must have been wired into power elsewhere?

Em-03 fem-02 b/l wire to circuit opening relay is a different wire?
The car ran for 2k miles with me the way it was!

Where does the b/bl wire go to it's next connection? driver or passenger footwell area?

Also, what would be a good switched 12v source?

satch

iTrader: (1)

How many miles doe the gauge cluster read?

The B/L wire which runs from the ECU to FEM-02 connects to a B/W wire which then runs to the circuit opening relay. The B/L wire comes from pin 3B at the ECU and not F-31 which you initially brought up, thus they are different wires.

If you are asking where the B/L wire that comes from pin 3B runs to it would go to the circuit opening relay via under the dash. Pin 3B has this wire coming in from the starting circuit and then goes outbound to the circuit relay. This B/L wire has voltage w/key to start and not key to on as it is part of the starter circuit.

A good switched power would be the B/W wire as previously mentioned. The B/W wire leaves the main relay and runs to the front side of FEM-02 and splits into two wires before arriving at this connector. Then there are two B/W wires on the emission side of this connector. These two wires would be side by side in the connector. After the emission harness side of the connector the wire unsplits into one wire so it can again split into two wires where one segment runs to pin 3I of the ECU and the other segment powers the engine solenoids.

hella24

iTrader: (8)

I was thrown off by the fem02 wire colors.

The car has almost 180k miles.

It seems I need to figure out why / how the f-31 B/L had power.

The fem-02 plug to the old split air doesn't plug into anything now and the b/l wire is uncut here as far as I can tell.
I will look around the fuse panel area for a cut in the fe-02 over the top switch side of the wire next. Thanks

hella24

iTrader: (8)

I connected the switched 12v line to the black/white wire you suggested and it runs again!

"Not all 12v switched is the same " was the key.

I never did find out what was powering the black/blue stripe wire up until this happened. Thanks for all your help.

satch

iTrader: (1)

Good to hear.

jjwalker

You just learned the difference between a true ignition and an accessory circuit.

Good job!

pfsantos

iTrader: (1)

Lol that's a third one. Accessory, ignition, and start!

jjwalker

I'll go ahead and add to this thread what I mean about "true ignition".

Ignition #1 = "true ignition" because it is powered up when the key is in the ignition and start positions.

Ignition #2 = NOT "true ignition" because it is only powered when in the ignition position but not during start or accessory positions.

Accessory = Powered when switch is in accessory and ignition positions but not powered during start

The above is true for most vehicles. The one thing that will never change no matter the vehicle is the definition of "ignition #1" as stated above.