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pvfahrer

Parasitic current drain ECU, EJ22 1992

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Hi,

first off, its my first post here, so please be kind if i am in the wrong category. My name is Andi, i have a VW Vanagon with an 1992 EJ22 most likely put of a legacy. I bought the VW with the conversion done by the PO and had to iron out some kinks in the beginning, now the car is running nicely. However, the battery (new) is getting drained when i leave the car in the street for a week. I have checked and the battery is getting charged by the alternator, so went and tested for parasitic current draw, and i found that there are about 200mA (0.2A) of parasitic draw. Reading up indicated that this is about 10 times higher than what is usually accepted as okay. So i went ahead and checked sources for the drain, I was able to figure out that when i pull the fuse for the ECU, the drain drops to 2mA, which is from the clock and the radio code. So th ECU itself draws the majorty of the current, i wen ahead and disconnected the alternator and the relays that are connected to the ECU, non of these had any impact on the parasitic drain. I am considering to try out a different ECU to make sure it is not just some weird defect to if (i read the rarely brake) but it would still be an easy test.   

So i am coming to my actual question, can somebody tell me what ECU is compatible with mine.

The one that is in the car is a F9 22611 AA930 A18-000 RF6

I found one in the bay that seems to be very close but i wonder if it really is compatible: F9 22611 AA931F JA18-000 RK3

 

Alternatively, maybe somebody here has a functional compatible ECU lying around and would be willing to loan this to me, i would ofcourse cover the shipping and either way whether i keep it or return it, come up with a compensation. 

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Any first gen non-turbo Legacy ECU should work.

 

Although, I HIGHLY doubt it is the ECU itself. More likely something in the wiring, as the power circuit all has to be modified when doing a swap.

My first thought, is the ignition coil. In the Legacy, this power wire comes straight off the ignition switch and that wire has to be tied into a new power source (I remember it, as I missed it a couple times...), if the person who prepped the harness tied that into an unswitched power source, that would cause a considerable drain.

 

I'd grab a test light and/or multimeter and start testing power wires at the coil, ignitor, fuel injectors, etc. with the key off. 

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4 hours ago, pvfahrer said:

I was able to figure out that when i pull the fuse for the ECU, the drain drops to 2mA,

Is this using the fuse holders from the 92 Legacy? If so, is it fuse 16 (15AMP) that you are pulling?

That fuse feeds 12v to Pin 12 (Yellow wire) of connector B58 (ECU 12 pin connector) ONLY with the Key ON and START positions. If it is hot all the time move the source of the fuse to the IGN wire from the IGN SW.

There are 2 other pins on the ECU connector B48 (22 pin connector) Pins 2 and 13 (Yellow/Red stripe) that get voltage from the IGN Relay contacts and the coil of the relay is triggered by the ECU and then kept closed with power through a diode from the alternator when the alternator is charging. Those two pins should be dead with the IGN key OFF.

In case you don't know, when looking at the wiring diagrams in the FSM the connector plugs are shown looking at the pin side and numbered left to right. Looking at the wire side of the connectors it is the same row but the pin numbers are backwards right to left.

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21 hours ago, Numbchux said:

Any first gen non-turbo Legacy ECU should work.

 

Although, I HIGHLY doubt it is the ECU itself. More likely something in the wiring, as the power circuit all has to be modified when doing a swap.

My first thought, is the ignition coil. In the Legacy, this power wire comes straight off the ignition switch and that wire has to be tied into a new power source (I remember it, as I missed it a couple times...), if the person who prepped the harness tied that into an unswitched power source, that would cause a considerable drain.

 

I'd grab a test light and/or multimeter and start testing power wires at the coil, ignitor, fuel injectors, etc. with the key off. 

 

16 hours ago, Rampage said:

Is this using the fuse holders from the 92 Legacy? If so, is it fuse 16 (15AMP) that you are pulling?

That fuse feeds 12v to Pin 12 (Yellow wire) of connector B58 (ECU 12 pin connector) ONLY with the Key ON and START positions. If it is hot all the time move the source of the fuse to the IGN wire from the IGN SW.

There are 2 other pins on the ECU connector B48 (22 pin connector) Pins 2 and 13 (Yellow/Red stripe) that get voltage from the IGN Relay contacts and the coil of the relay is triggered by the ECU and then kept closed with power through a diode from the alternator when the alternator is charging. Those two pins should be dead with the IGN key OFF.

In case you don't know, when looking at the wiring diagrams in the FSM the connector plugs are shown looking at the pin side and numbered left to right. Looking at the wire side of the connectors it is the same row but the pin numbers are backwards right to left.

Thanks folks! i will look into all these suggestions, the fuse that i am pulling is an additional in-line fuse in the conversion wiring loom, i will check what pin the 12V input is connected to and if it is hot all the time, but i am almost certain that it is. What pin is the main power-in supposed to go to? 

I have already looked into voltage output on a few sensors in off position, i found that the VSS, the inhibitor switch and parking break indicator light all show 5V when ignition is on or off, i believe this should not be the case.

However the current draw is 0.2A when ignition is off and 3A when on (engine not running), so i guess the ignition relay or at least parts of that circuit work properly.  

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Check pin 12 on the 12 pin connector. Does in have voltage and does it go away when you pull that fuse you mentioned.

The VSS is wired into the Transmission Control Unit on auto transmissions. Is this a 4EAT? Check what I posted here. There is a pic of the TCU connectors.

 https://www.ultimatesubaru.org/forum/topic/171518-1990-legacy-fwd-automatic-transmission-problem/

 

You can get the 92 FSM wiring diagrams here. http://jdmfsm.info/Auto/Japan/

I also found this. They fit 8 different models in 92.

Engine Control Module

Part Number: 22611AA933
Supersession(s): 22611AA930; 22611AA931; 22611AA932

I found this on one Subaru site for the 22611AA930. Production Date: 199105 - 199204

I looked up a 92 Legacy at subarupartsdepot.com and found this.

  • SKU:22611AA933
  • Other Names: EGI Control Unit
  • Description: Legacy. Without turbo, manual trans

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On 9/25/2020 at 2:27 PM, Rampage said:

Check pin 12 on the 12 pin connector. Does in have voltage and does it go away when you pull that fuse you mentioned.

The VSS is wired into the Transmission Control Unit on auto transmissions. Is this a 4EAT? Check what I posted here. There is a pic of the TCU connectors.

 https://www.ultimatesubaru.org/forum/topic/171518-1990-legacy-fwd-automatic-transmission-problem/

 

You can get the 92 FSM wiring diagrams here. http://jdmfsm.info/Auto/Japan/

I also found this. They fit 8 different models in 92.

Engine Control Module

Part Number: 22611AA933
Supersession(s): 22611AA930; 22611AA931; 22611AA932

I found this on one Subaru site for the 22611AA930Production Date: 199105 - 199204

I looked up a 92 Legacy at subarupartsdepot.com and found this.

  • SKU:22611AA933
  • Other Names: EGI Control Unit
  • Description: Legacy. Without turbo, manual trans

thanks for the info on the ECU, unfortunate somebody bought it of the bay before i could act... 

I am using the Volkswagen automatic transmission so i don't use the TCU, going to check the pins later this week!

 

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