So i finally got my lazy ass around to putting together a small how-to on using the 2.5rs coil when doing a 1.8 liter swap to 2.5 (ej251) swap. here we go. This applies to 2000-2001 RS engines!! I'm not sure about earlier or later models. Also, the donor car was a 95L, but wiring diagrams from 93-95 for this is the same.

Step 1. Cut off connector for ignition coil from 2.5rs harness. save some wiring to extend from 1.8 harness.

2. cut off and throw away 1.8 coil connector (harness side)

3. Wiring. The RS coil uses a 4 pin dark grey connector. While looking at the connector end (female pin side) the pins go simply enough (left to right)- 1 2 3 4

4. At this point you can either de-pin the RS connector and supplement your own female pins with the wire colors of the 1.8 harness to make it easier to look at.

Pin #1 -- Blue/Red wire from 1.8 harness
Pin #2 -- Red wire from 1.8 harness
Pin #3 -- This is going to need to be a wire going to a body ground. Nothing more, nothing less. Just a ground wire.
Pin #4 -- Red/Green wire from 1.8 harness

Obviously soldering these wires together is your safest bet to ensure good wire integrity. Thats that for wiring up the coil. Now, onto bypassing the ignitor from the 1.8 liter.

Step 1. Unplug ignitor

Step 2. Looking at the connector the same way, (female pin side) the pins go 1 2 3 4 5 6 (left to right)

Step 3. Make 2 jumper wires, both sides with male ends that will fit into the pins on the ignitor connector.

Step 4. Jump pin 1 to pin 5
Step 5. Jump pin 2 to pin 6

Leave pins 3 and 4 empty.. There is no wire going to pin 4 anyways..

Thats it. Its really pretty simple, if i'm not clear on anything, just let me know. Thought i'd help some brothers out since info is hard to find sometimes.

Cool!

dumb question i know, but whats the ignitor?

Im used to working on vws with distributors lol.

PS THANKS ALOT! this will answer alot of the questions that swappers have regarding the wiring aspect of the 2.5 swap.

The ignitor is what actually converts the current, while the coil is what generates the high voltage. On the RS, the ignitor is built into the coil. On earliers subbies, it is seperate on the firewall.

While this is a very simple conversion, it is great to see someone write it up. When I had some similar issues converting a '90 Legacy with wasted spark to WRX with coil on plug, there was nothing out there at all. I don't think a lot of people realize how much it helps others to have documentation out there...

any pics or manual diagrams of the ignitor on an early 90s impreza? so I know exactly what we're talkin about here? lol

I "think" that its right over the rear engine/tranny mount thingy. Right behind the throttle body...

word, ill holla at that area and see what i can find, im sure ill be able to scope it out, just want to get everything in order before i go up there this weekend so I can be sure to have it all done preferably before noon on sat so i can drive it around all weekend :)

Yeah,
It is right above the pitch rod. It is a little black plate with a 6 pin connector running into the base...

oh ok, i know exactly what your talking about. Thanks!

how do you know, on the 2.5RS plug, which is #1 pin and so forth? which way do I look at it?
The colors I see are

Blue
Brown
Yellow/White
Red/Blue or green or something

anyone? :confused:

Well, I just soldered mine together so I hope it's right. Maybe somebody can confirm the wire colors?

The Black wire (aka brown) is the ground. It goes to the ground loop in the 2.5 harness so that should be pin #3.

What has me kinda nervous is that the Red and green wire from the 1.8 harness goes to the Blue wire of the 2.5 harness and the Blue/red wire from the 1.8 harness goes to the Red and Green of the 2.5. you'ld think the two red and green wires would go together.

I'm working with a '93 wagon getting a '99 2.5 but it sounds like you've got the same colors to work with.



Matt W.

the info i provided was from my personal swap.. 2001 ej251 into a 95L. I can't guarantee wire colors from other years, but 2000 and 01 seem to share everything identical as far as wiring. And 93 to 95 seemed to be the same from the wiring diagrams i've seen. At least for this particular section.

Don't let the wire colors trick you.. They change colors for no reason between generations for whatever reason.. If i had a scanner, i'd scan the diagrams in, and could better show whats going on..

I have a 95l with an ej25. Would there be any advantage to eliminating the igniter and converting to the four separate coils instead of the double one I have now?

this isn't converting to individual coils.. Just using the orginal coil on the rs engine.. Which is the ignitor and coil built into each other.. Eliminates the need for custom wires

So the ignitor is built into the coil pack on the RS? Does the WRX have the individual coil packs? I guess if they do, they probably have sequential firing as well, because the waste spark stuff probably wouldn't work on a vehicle with four seperate coils? Crap, I need to get an STI engine asap, my ignition system is feeling inferior! :lol:

Bitchin' thread.

http://i4.photobucket.com/albums/y120/83Rabbit/ignitor.jpg

Heres my jumper bit.... figured Id throw it out there, its not a permanent solution the exposed teminals and all but it gives you a very good idea of what needs to be done for the ignitor.

thats essentially what i did..

I finally got my swap to the point of starting Monday. It started right up and ran like, well, like it is supposed to. Sounds cool too. (Exhaust Video link) (http://www.clipshack.com/Clip.aspx?id=F0F879349F659092) :banana:

Idle is pretty steady, just need to get the rest of the car back together for a road test.

As far as the wiring the coil, the wires went together like my prevous post so the colors not matching was the right way. I left the wires from the 2.5 harness plug about 1" long, I should have made them a bit longer as the coil is father away on the 2.5 so the coil wire was a bit tighter than I'd like. The ignitor I just cut the connector off and spliced the wires since I don't plan on needing that again :D The fuel injectors I just trimmed the tabs off the side of the connectors and they clipped right in.


Matthew :cool:

point of note- if u have a 98 dohc, you directly plug everything in. its teh same layout as the EJ18

point of note- if u have a 98 dohc, you directly plug everything in. its teh same layout as the EJ18

please expand on this....you still have to make the two jumper wires?

The 97-99? dohcs don't have the ignitor built into the coilpack, it is seperate like my 95 and mounted to the firewall. That is why he is saying it just plugs right in, because it does. I'm not sure when they changed over, but apparently the 01 model has the ignitor built into the coilpack, just saves a little wire. Frankly, mounting the ignitor on the firewall is a better location for heat dissipation, I'm surprised they would integrate it into the coilpack.

The 97-99? dohcs don't have the ignitor built into the coilpack, it is seperate like my 95 and mounted to the firewall. That is why he is saying it just plugs right in, because it does. I'm not sure when they changed over, but apparently the 01 model has the ignitor built into the coilpack, just saves a little wire. Frankly, mounting the ignitor on the firewall is a better location for heat dissipation, I'm surprised they would integrate it into the coilpack.


i know 2000+ has the ignitor built into the coilpack. I'm not positive on the 99's.. I think its basically when they switched engines over to the SOHC as far as i can tell.

That sounds about right. Me no likey ignitor built into coil. = more expensive part. Glad to have seperate parts. :)

Alright this is an important question I have. I am in the planning stages of putting in a EJ257 (USDM sti block) in my 95 L (1.8) what obstacles will I have since the STI has the ignitor built into the coil vs how it is laid out in my L now with them separate? I already have an e-manage installed.

Damnit, why couldn't I have found this thread when I was doing my 2.5 swap??!!! I ran on the 1.8 coil with modified wires for months (right up till it blew)...!!!

GRRRR

so bumpage, for future swappers

Thanks a ton, this is the last step I need to finish the swap I started yesterday!