WRX ignition coils on EJ22T ECU

[DaveK]

Hi all,

I've searched and searched but not coming up with much on my specific question. I would like to upgrade to WRX ignition coils. I've seen writeups on how to convert an EJ20G ECU'd car to run WRX coils, and I've seen writeups on making EJ22T ECU'd car run EJ20G coils. Here's what I've got:

- EJ22T ECU (1994)
- EJ20G motor with TD05h turbo (1996?)
- 2002 WRX coils with wiring pig-tails

From speaking with some folks, it sounds like you can simply snip wires at the EJ22T ignitor and run them out to the new coil on plug assemblies, maintaining the wasted spark setup. I'm a measure twice cut once kind of modder, so I'm wondering if anyone can confirm this. Here's what I've figured out by looking at varying wiring schematics:

The wiring at the EJ22T ECU #47 connector is as follows (but I don't know colors and know that even if I did, there's no guarantee the colors are the same once the wiring is out at the ignitor):

- Pin #9 is for ignition signal on coils 3 & 4
- Pin #10 is for ignition signal on coils 1 & 2
- Pin #15 is for ignition ground (is this be ignition key on position type thing, not to the ignitor ground?)

The wiring on the 2002 WRX coils is as follows:

- Pin 1 is RY and carries 12v signal
- Pin 2 is BY and is the ground
- Pin 3 is GY and is the trigger

What I couldn't find is the wiring schematic at the EJ22T ignitor. I wasn't able to get the ignitor pulled off the firewall to see what wire colors are there, but my chilton manual shows the following, but no positions:

- B is ground
- Y/Bw is coming from the ECU
- R/G is going to the coil pack
- G/Y is coming from the ECU
- L is going to the coil pack

Any help or thoughts much appreciated!

Dave

[subaru_styles]

it seems reverse productive to use the 2.2t ecu since you have a 20g motor. might as well use a 20g ecu with wrx coil swap

[DaveK]

I don't have a 20g ECU. I do have a full EG20G wiring harness, but I absolutely hate wiring work and merging harnesses. From what I was told, the EJ22T ECU can control the EJ20G motor with no issues...well, other than the factory EJ22T ignition not really being up to the task.

FWIW, I've heard that many folks with EJ20G ECUs have terrible hard start problems when the weather gets cold. This car is my weekend warrior to Steamboat Springs...a damn cold place and I can't have the car not starting on me.

Dave

[Legacy777]

Dave,

Have you d/l'd the factory manual from me. It has much better wiring diagrams & info than Chiltons. If not, check out the stuff you need to know forum.

As for using the WRX coils, in theory I think you could do the wiring so this would work, but what is going to be different is the dwell settings for the coils. I really don't know if it's a big deal though.....so if you can get the wiring sorted out, it would be interested to see if this works.

Once you get the wiring diagrams from me, let me know if you need any additional help sorting through them.

[subaru_styles]

you dont need to merge harness's to run the 20g

http://bbs.legacycentral.org/viewtopic.php?f=19&t=43959

http://bbs.legacycentral.org/viewtopic.php?f=19&t=43744

[kimokalihi]

I thought without tuning the japanese ecu would run poorly because of our low octane fuel?

[mike-tracy]

Depends on the ecu. I have the least aggressive 20g ecu (a wrx wagon one), untuned, and it runs fine as far as I can tell. A Z4 Sti one on the other hand...

[cj91legss]

I've wanted to o COP for awhile now

[DaveK]

Damn, all this uncertainty has me thinking maybe I should just swap out the old stock fuel pump for this walbro I picked up and hold off on the coil pack thing for a bit. Maybe I should try and source an EJ20G ecu for one of the less aggressive ones...but will those work ok with the TD05 turbo, or are those meant for TD04 equipped cars?

Dave

[mike-tracy]

The least aggressive ones are the WRX wagon ones, and are designed for a td04-sized turbo and 440cc injectors.

I am running mine with 440cc's, and... a td05. I'm running all the stock equipment, stock boost for the ecu (10PSI) and everything runs fine now. I'll be getting the ecu chipped with a robtune once I can afford that + the injectors.

Full 10psi arrived at 2.5k rpm with my old td04 which was a hoot (as people who drove my car can attest. Now is it at 3k rpm with the td05. I believe that bypassing the BCS with a MBC would help spool time.

I have a full ej20g setup.

[oldscoobyturbo]

I will 2nd that the ej20g hates cold starts my RS-RA is not very good when I cold start it in the winter and that's in my partially heated garage!

[mike-tracy]

^^3rd - with temps in the 40s and 50s in the morning, it's already not starting too nice.

[kimokalihi]

Really? Strange. Mine starts just fine every time. Runs awesome. Even in 15-20F it still starts fine. 0_o

[mike-tracy]

You don't have stock ej20g ecu lol

[kimokalihi]

Oh I was thinking you guys had rob tunes too. Nevermind. What octane fuel they run in japan? 98?

[DaveK]

From what I've heard on other forums, the rating used in Japan isn't the same rating used in the US, so its not as much of a difference as 98 to 93 (or 91) would actually indicate, but there is still a difference.

FWIW, I've dug into some other areas of the car so this coil thing is on hold for at least a bit. Had a leaky oil pump seal, so knocking that out along with a full timing belt service (belts, pulleys, water pump). Also have a WRX catless downpipe and STi axle back exhaust that'll be going on. Thinking I will try to stick the stock legacy single cat mid-pipe in there.

Dave

[Legacy777]

I don't think the cold start is related to the fuel octane being difference. As Dave pointed out there's not much difference, you can check out some of the various fuels on the wiki page

http://en.wikipedia.org/wiki/Octane_rating


Just out of curiosity, anyone running an ej20g ECU have you tried running 89 octane or less and if so, did the cold start up issue change, better or worse?

[wtdash]

Hi,
I apologize if this is too much of a thread 'hi-jack' but apparently I 'missed the memo' on the CoP being better than the stock coil pack? I guess that makes some sense since the EJ22T is the only EJ-series turbo engine NOT using them, and it also runs the lowest boost level @ 8.7psi:

EJ20G ECU INFO
Here's an incomplete list :
U8, 2C - 1993/1994 WRX - 11.47psi
W6 - 1993 WRX RA - 11.47psi
W9 - 1994 WRX RA - 11.47psi
SA (STi chipped) - Ver1 STi (Sedan and Wagon) - 14.94psi
SB (STi chipped) - Ver1 STi-RA - 13.64psi
SC (STi chipped) - SAME AS Z4 - Ver2 STi Wagon - 12.78psi
Z4 - 1995/1996 WRX - 12.78psi
Z5 - 1995/1996 WRX-RA - 12.57psi
6K - Ver2 STi Sedan - 13.34psi
7K - Ver2 STi-RA - 13.19psi
Prodrive UK ECU (Prodrive Chipped) -- SAME AS 6K - 13.34psi
1C, 3B, V9, V5 - All WRX Wagons 10psi, dropping to 6.8psi
V7, 7D, 6D - 1993 to 1996 UK/Euro 11.47psi

Have you looked into options for other coil packs? I know the Mopar/SRT4 coil pack is supposedly an upgrade (requires modified plug wires), and may be others.....probably easier than adding Cop.

RE: the EJ20G ECU:
I also had cold (weather)-start issues, but it wasn't terrible - mainly annoying - as the car always started right-up on the 2nd try....and always started fine once warm....you'd probably want to use an engine heater in Steamboat anyway (great resort, BTW!).

GL,
Td

[DaveK]

From what I gathered, the stock EJ22T coil packs are garbage and lots of folks were upgrading to the EJ20G coils especially when wanting to run more boost. However, the EJ20G coils were know to fail on a regular basis (plastic cracking with age), and now it seems folks with full EJ20G swaps were updating (not sure if an upgrade technically) to the US WRX coils. I have a set of EJ20G coils, but figured why deal with an upgrade that might have issues and instead just jump to the ones that are readily available in the US. Hopefully the timing belt job goes smoothly and I can experiment with the coils this coming weekend.

Wish I had time to ski there, but I'm busy instructing here: www.winterdrive.com

Dave

[wtdash]

Wish I had time to ski there, but I'm busy instructing here: http://www.winterdrive.com

Dave

Hmmm, I'd like as much 'practice' time as I could get.....nice gig!
TD

[Legacy777]

I'll throw my two cents in regarding coil packs & COP.

I would have to disagree that the EJ22t coil pack is garbage, it's not. The diamond coil pack is a pretty decent coil pack. I don't have any figures right now on its specific capacity, but it works fine. The issues I'm sure you've read about is when people up their boost, they have misfire or other issues unless they narrow the spark plug gap. This is really an issue of the entire ignition system.

I run an MSD Dis-2 ignition system that goes between the igniter and coil pack. I have run 19-20 psi without any misfires or any ignition issues whatsoever. I attribute my lack of issues due to the DIS-2 ignition system that bumps up the voltage of the ignition and also produces multiple spark events. This is the info from MSD on the Dis-2:

Spark Duration: 20°- 4-Cyl. Max Sparks - 12
Energy Output Max: 105-115 milliJoules per spark.
Output Voltage: Primary (into coil): 460-480 volts
Secondary: (w/stock coil) 43,000 volts


With that being said, the issue with the coil pack setup that hurts it, especially with higher revving engines is that since it is a wasted spark setup, it fires on both the power and exhaust stroke, so the coil has less time to "cool" so as you start bumping up the rpms, the problem gets worse and you can either fry the coil or have ignition irregularities.

The COP setup contains the igniter & coil all in one setup, and is referred to as a "smart" coil where the ECU can directly control the coil's dwell. This is pretty much the standard across most cars now a days. Some of the less expensive ones may still have a coil pack setup, since they do work fine.

My ideal ignition setup would have a separate igniter & coil and use a DIS-4 ignition to boost the ignition voltage. IMO, that's the one draw back of the COP setup. The problem is finding a coil that has good specs and is small enough where I can mount it and rewire everything. I really haven't found anything yet. The non smart LS1 coils are a possibility, but are likely still too big. For the time being, I've put that project on the back burner since the current ignition system works well.

[DaveK]

Ok, I will rephrase my thoughts on the coil pack. In stock configuration they must not be that great if I have to re-gap my plugs to run less than 15 lbs of boost. I have already put in fresh plugs and the shop that installed them is familiar with EJ20 swaps and my issues, so I'm pretty sure I'm not running any sort of large gap. Guess I could pull them out to double check - but what gaps are recommended for 10-12psi on the stock ECU?

My point of reference is that on my Evo which has COPs, I run a gap of about 0.25 and 30psi with zero blow out issues (running E85 fuel). Of course the other issue I've got (although minor), is that the EJ20G heads are of a different shape and don't have a provision for mounting a coil pack. The plug wires I've got are a bit on the short side too...so all in all, I just want it outta there.

Made good progress on the timing belt, oil & water pumps, and new pulleys last night. Not sure if I'll get to trying this wiring coil pack swap soon or not. I do believe that my buddy Max is running that exact setup on his EJ20G motor/EJ22T wiring harness with success.

Dave

[wtdash]

Hi,
Stock gap is .039-.043 per Owners Manual. The NA and turbo EJ22 use the same plug and gap: NGK BKR6E-11

Bumping to 10-12 over the stock 8.7psi, shouldn't require a gap change, IMHO. But I'd probably pull it in to .035, to help.

I think running 15psi should require less gap, and it sounds like something similar to your EVO experience would work.


When I used the Revtronix chip on the stock ECU and had the Rob tuned EJ20 ECU, I changed to ~.028, IIRC, as I was pushing 16-18 psi.



Td

[DaveK]

Thanks for the info and wow, that's a huge gap for a turbo car! FWIW, I'm running ~6psi now (manual boost controller fully backed out, running on wastegate pressure) and I've got some bad something going on. The car feels like its breaking up and then bucks pretty bad around 3500rpm.

I've recently replaced the fuel filter (2x now in ~5,000 miles just to be safe), and also dropped in a brand new high flow walbro, but no change noticeable from either the last fuel filter or fuel pump...so that's leading me to the ignition.

Dave

[wtdash]

Hmmm, that's an issue I've read of b4, but can't recall what was the resolution....hopefully JC or one of the other smart guys will reply.

Td