How-To: Convert To GD WRX Coil On Plug w/EJ20G ECU

[James614]

Ah OK. I can see how that can cause issues, with the valve covers being insulated by the gaskets and grommets on the valve cover bolts.

[SILINC3R]

Yea I never even thought about it until after I fixd the issue. You live and you learn

Also I have stickied this thread

[kimokalihi]

Ro-sham-bo you for it mike. I go first...

lol you two weren't the only ones! I was laying in bed the other night trying to fall asleep thinking about tony's issue and it dawned on me to check his pics of his grounds and I spotted it! He chose a different ground than I did and one of them was on the head and the other side was on the valve cover. Texted him immediately.

Keep your two bucks tony you'll need it for that coolant funnel!

[cj91legss]

Lol, yeah invest that elsewhere.

[rob]

Repositioned ground with added chasis ground.

[/quote]

Unless that extra wire to chassis ground is directly attached to a chassis to battery ground point, then are creating a likely ground loop that can cause all kind of funny problems.

-Rob

[James614]

I had to read up on ground loops to understand where you were coming from. So would you suggest those of use that have the coils grounded to the mounting bolt instead run the grounds to the main ground on the intake manifold?

[SILINC3R]

That wire is grounded to the ground point where the canister mounts. There is another ground there and haven't had any problems.

[rob]

I had to read up on ground loops to understand where you were coming from. So would you suggest those of use that have the coils grounded to the mounting bolt instead run the grounds to the main ground on the intake manifold?

Any point on the head should be fine. Even a cam cover bolt on the head side of the grommet would be fine. The issue is there is more than one path to the battery ground.

That wire is grounded to the ground point where the canister mounts. There is another ground there and haven't had any problems.

There isn't a need for the second wire (assuming your head grounding point is good shape) and could be causing noise issues that would show up in non obvious ways. It is probably ok, but if it were me, I would remove it. It caught my eye when scanning the pictures, so just thought I would pass it on.

-Rob

[Legacy777]

I typically run my critical ground points back to the battery to eliminate issues. That's what I did for the ECU ground point on the back of the intake manifold.

[RckyMtnLegacy]

Wired up everything and just got it to crank for the first time in 4 years but no fire.

[RckyMtnLegacy]

Check all grounds and the only one we are not getting continuity from is the MAP ground we repinned to to b48 21. Where does this wire go?

[Legacy777]

Check out my ECU I/O spreadsheet.

http://bbs.legacycentral.org/viewtopic.php?f=19&t=53822

B48 pin 21 is for the coolant temp sensor and shouldn't be tied into the MAP sensor ground.

[RckyMtnLegacy]

Would this cause my crank issue?

[RckyMtnLegacy]

We checked all grounds from ECU and only found MAP ground open. No REF or 12v to cam or crank sensor but checked wires to ECU.

[RckyMtnLegacy]

Check out my ECU I/O spreadsheet.

http://bbs.legacycentral.org/viewtopic.php?f=19&t=53822

B48 pin 21 is for the coolant temp sensor and shouldn't be tied into the MAP sensor ground.

21 was empty to begin with I never depinned it, I only merged 5 into it following the thread. Still just cranks for days no fire. Could the ECU be bad and not sending signal to the cam and crank sensor in turn giving 0 spark?

[Legacy777]

The crank and cam sensors generate a signal to the ECU to read/interpret. So I would start there, however I think you would need an oscilloscope to check that. If those are good, it could be the ECU.

[RckyMtnLegacy]

So I was able to check the sensors with my multimeter on AC and both are good. Cam sensor has voltage going to ecu. Crank sensor doesn't. Found crank sensor Harness after the sensor connector to be a mess. Need to find shielded wire to re wire to ecu

[RckyMtnLegacy]

When I say a mess I mean a mess

[Legacy777]

Yeah, that's definitely a mess!

Look at microphone cable. I don't know if it'll have two leads in there, but if you can find one that does that may be an option. I seem to recall someone posting information about where to get shielded wire so you may want to search.

[RckyMtnLegacy]

I have $15 for whoever can help lol. After checking the cam and crank sensors we are only getting max 10 mV between the terminals while cranking. We now have injector pulse but no spark.

[Legacy777]

Did you replace the wiring?

[RckyMtnLegacy]

Replaced the crank sensor wiring from the harness connector to the ECU. I have also printed out the USDM and JDM pinouts and am going through each terminal to match everything up. I would like to run a couple things by you and let me know if I need to move this to my build thread instead.

Are these the same thing just worded different? Left is USDM pinout and right is JDM pinout descriptions.

Self-Shutoff Control and POWER TO MAIN RELAY
IDLE SWITCH and TPS
IGNITION SWITCH and FUEL PUMP RELAY IGN
POWER SUPPLY and MAIN RELAY IGN
BACK UP POWER SUPPLY and FUEL PUMP/IGN SWITCH

Other items I had questions with are:

I assume MAP on USDM pinout is considered BOOST PRESSURE in JDM pinout?

What is TI MONITOR? USDM has one JDM does not

[Legacy777]

Can you post the pin outs or if you got them from me or somewhere else, let me know which ones you're using and I'll take a look.

[RckyMtnLegacy]

Check out my ECU I/O spreadsheet.

http://bbs.legacycentral.org/viewtopic.php?f=19&t=53822

B48 pin 21 is for the coolant temp sensor and shouldn't be tied into the MAP sensor ground.

I am still confused by this when the write up explains to do this:

MAP ground (B48-5 ; Red) :: Merge with B48-21. B48-5 is used for the stock JDM EJ20G cat efficiency EGT sensor. Not having an the stock EGT sensor has zero impact on how the ECU runs. The EJ20G harness combines the MAP sensor ground with all other sensor grounds at B48-21.

[RckyMtnLegacy]

Can you post the pin outs or if you got them from me or somewhere else, let me know which ones you're using and I'll take a look.

https://redirect.viglink.com/?format=go ... M%20UK.pdf

http://www.surrealmirage.com/vrg3/ecupins/