I'm trying to make sure it's compatible with our '98 JDM Ej20G

22611 ac720
a18-000 d28

Thanks

 

http://www.ebay.co.uk/itm/Subaru-GC8...item53e7cbe90e
codes match to a (1S ECU)

 

Thanks, I saw the numbers matched on that earlier, but is there anyway to confirm it's listed right and my computer is in fact from a 97 or 98?

As I understand it the 97-98 are interchangeable. It's already wired and trying to start, so thats what I'm going with, so if anyone can confirm or deny that would be helpful

 

Yes, the 1S comes from a MY97 JDM WRX impreza saloon. The ECU is 3 plug and will be compatible with any 97/98 impreza wiring harness. (it will not be compatible with the older 4 plug version from 92-96 nor the later three plug 99-00)

 

ok, so since this is a JDM ej20G motor and the above mentioned computer, in a USDM 96 Legacy L, will we need to do the wiring/conversion for the dual ignitor set-up, or can we just wire the pin outs on the ECU to the corresponding locations on the JDM motor/sensors and have it run?

We've done the latter and can't seem to get consistent sparking, so it's leading me to think we have an incompatibility, or a faulty ecu/ignitor/coil?

 

for reference, the full Engine barcode is:

EJ20GDX1NY 308554 9B10

 

Although the 1S was fitted to cars with the "phase 1.5" engine (EJ20K) it should run a EJ20G engine without problems.

I don't know much about a USDM legacy though. The impreza runs a wasted spark system through an ignitor so the two ignition systems sound compatible from your description. Is your ignition amplifier still getting hot? That didn't sound right but I'm not sure if you've cured it.

One thing to watch is the crank and cam sensor inputs - these are reversed on UK vs. JDM cars, and if run without swapping will cause the spark to fire at the wrong point. (This prevents swapping ECU to bypass the immobiliser) I don't know whether they are swapped on the USDM vs. JDM models or not.

 

Hi Chief,

The Legacy ran a wasted spark too, but all the electronics are from the JDM EJ20G EXCEPT the MAF, which is off the Legacy. We have swapped the ignitors (same part number for both EJ20 and Legacy) with the same results. Both get too hot too touch within about 10-20 seconds. We have not cured this to this point.

We wired the cam and crank sensors per the pinouts for "without immobilizer". This is where we are at now. We did swap them around (with immobilizer) and got attempted backfiring through the intake, so like you mentioned the spark timing is wrong.

For a better explanation and part numbers, you can see this thread I started (https://www.scoobynet.com/general-te...l#post10671865) and have not gotten any replies to this point.

Thank you for your help to this point, and any future input.

 

OK, it sounds like you've checked the cam/crank sensors and got them right.

The ignitor module should not be getting that hot - it sounds like something is not wired up right. Difficult to know what though without getting a wiring diagram out and double checking everything.

I'm not familiar with the USDM legacy though so it makes it difficult to make suggestions, although the ECU designs are similar I believe so I'd be surprised if it was that different.

 

We had a bad ground (ignition) inside the harness on the car side, that was allowing 11VDC to the ignitor, not the max 3.4VDC. That is fixed. The ignitor is cool to the touch now (imagine that).

Funny thing is car still (barely) runs the same, hard to start (sometimes will start at idle, sometimes needs WOT, but nothing really in between will start it).

Once it's running - it is running on 2 cylinders, but it varies which 2. We either get the right side or the left side (and occasionally one other cylinder, totally random) to blink the timing light, but can never get all 4 to fire. Since it's the right or left side, It tells me (correct me if I'm wrong) the ignitor is firing both signals 1&2 (front coil) and 3&4 (rear coil). This leads me to think the coil is bad as the signal is "getting in" but not "getting out". Whats weird is that is the same end of both coils, not both ends of the same coil.

Coil is a Diamond F-569 and ohms out at .8 across both pins 1&2 and pins 2&3.
The coils ohm across at 20.4K and 20.2K.
some searching we've found is that the .8 is barely acceptable and others have bought brand new coils at .89 and they work fine. The coil resistance is within the specs I found of 17.3K to 23.4K.

I don not have an LED testlight to check for pulse on both ignitor feeds, but I think they are fine as both coils are firing.

Cam and Crank sensors both ohm out at 2.154 and increase as they are moved towards my metal table top. I have not found the specs, since both sensors read and act exactly the same to 3 decimal places, I'm ASSuming they are both good.

When we swap the cam and crank signal terminals, the car wants to backfire through the intake, so I think we have those right.

any thoughts or input from this point?

 

Spark seems to follow coil wires, but on left or right half of each coil, not one coil or the other. If we swap plug wires from side to side, the spark goes with them.

Yet when we pulled the wires at the coil and checked spark it was at all 4.

Also we checked the end of each wire after disconnecting from the plug and using a screwdriver to ground and got spark.

Could the 2 wires be failing under the load of the spark plugs? The plugs fire with the other wires so I'm out of ideas on what it could be??

We ohme'd out the wires and got 1&2 @ 10.9K, #3 @ 7.9K, and #4 @ 13.9K

1&3 are the wires that are firing regardless of which side they are mounted on.

 

for those following (laughing) along at home, we got new information yesterday that we have a K motor, not an EJ20G like the front cover barcode states. Apparently it was replaced someplace before we got it.

We also think we may have the Impreza Rally Edition Computer, which is mapped all wrong for our motor. It's looking for a bigger CAM, MAF, Ingectors, and Turbo...

We're making some calls and talking to some people to confirm these things, and find the proper ECU.

The spark thing was corrected with new wires, the high internal resistance on the old wires made the spark intermittent. The new wires ohm out at just over 1K