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EA-82 Distributor/Coil Voltage Question


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6 replies to this topic

#1 BirdMobile

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Posted 16 July 2014 - 03:27 PM

Hello!

About a week after my EA-82 Rebuild for my 1987 GL (Carbed), my fuel pump control module (6 pin Mitsubishi cube) died. I figured out the wiring, and jumpered the keyed-12V wire to the fuel pump power wire. Works fine.

Now... the other half of the story. Apparently, the distributor/coil ignition system ALSO gets its power from this module. I jumpered the keyed-12V wire to the distributor/coil wire, and that works fine (for the last 2 weeks) as well.

My question:

I showed my fix to a mechanic friend, and he told me I might have a problem... he says that many distributor/coil systems run 12V when starting, then some lower voltage (around 8V) when running, He thinks the fuel pump control module "shifted" the voltage, and that by running my disty/coil at 12V all the time I'll fry them.

Is this true? Do Subaru distributors and coils run at 12V all the time, or only at startup? If only at startup, what voltage do they like during normal running?

Much appreciation for any feedback!

#2 Gloyale

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Posted 17 July 2014 - 11:58 AM

No it's 12V all the time.......

 

And it should not GET power from the Fuel pump unit........The fuel pump unit is provided power by the coil wire circuit.

 

Should be 12v+ on the Black/White wire to both the Fuel pump control and to the coil + side.

 

The Fuel pump control unit DOES also power the electric choke, and the cutoff solenoid, and bowl vent solenoid.......so if you didn't give those power also that can cause running issues.



#3 BirdMobile

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Posted 17 July 2014 - 12:05 PM

Interesting. Apparently I have an "open" in the harness on the black/white disty power wire then... it measures 0V to ground with key on. Just assumed the module supplied it with power after measuring this.

Two of the blue wires (Blue and Blue/Black) also seem to power the module - I'm measuring 12V when key is on at the Blue wire, and 12V when key is on (but NOT when starter motor is active) on the Blue/Black. Is this correct, or do I have another problem in the wiring somewhere?

I'm currently taking the power for the fuel pump and disty from the solid Blue wire - it's working fine, but I'd like to have things wired correctly if possible.

Edited by BirdMobile, 17 July 2014 - 12:59 PM.


#4 BirdMobile

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Posted 17 July 2014 - 12:36 PM

Just a side note... does anyone have a schematic they could post for the fuel pump module wiring to the car? Or at least a functional description of the 6 wires and where they go?

What I know for certain:

Black - Ground
Black/White - Distributor/Coil +12V Power
Yellow - Distributor/Coil Neg. (Tach Pulses)
Blue/Red - Fuel Pump +12V Power
Blue - ?
Blue/Black - ? (Seems to be keyed +12V, except when starter motor is engaged)

The module is Subaru part # 22631AA080,
Mitsubishi part # K8T65073
.
.

Edited by BirdMobile, 17 July 2014 - 02:29 PM.


#5 Gloyale

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Posted 18 July 2014 - 11:20 AM

Black/white wire should get power from fuse 11 (Ig. on and start)

 

Blue/Black gets 12v+ from fuse 14 (Acc. on and Ig. on.......not in start)

 

Blue/Red supplies 12v+ to fuel pump

 

Blue supplies 12v+ to Choke, Vent solenoid, and Cutoff  (anti-diesel) solenoid

 

Black is Ground

 

Yellow is tach pulse.

 

I'd start by checking fuse 11 for power with key in Ig. on



#6 BirdMobile

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Posted 18 July 2014 - 11:36 AM

Thank you!
I'll start checking... wonder why my blue wire is keyed +12V? Interesting.
Appreciate the info!

#7 Gloyale

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Posted 19 July 2014 - 09:33 AM

Thank you!
I'll start checking... wonder why my blue wire is keyed +12V? Interesting.
 

 

My guess is someone has jumpered a wire to the Choke.....look at the engine wiring see if anything has been chopped/spliced/added.






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