Subaru Impreza GC8 & RS Forum & Community banner

1 - 4 of 4 Posts

1999 Impreza 2.5rs
1 Posts
Discussion Starter #1
So I just want to start of with stating the whole purpose of this thread. I want to be as detailed as possible with it to give a true description for anyone who is looking to do a swap themselves. When I began my swap I had trouble finding a lot of straight up answers on what works and what doesn't and I'd like to solve that issue as much as I can. I also think it's an interesting build so far and will never be done for anyone who likes to follow builds. And to become web famous of course since that's the new American dream, jk. Just trying to share my experience and build with everyone :corn:

Me :naughty:: I have been working on cars since I can remember. I took a two year high school automotive technology at the top CTEC/VOTEC in NY state for automotive, according to NATEF and SkillsUSA. Placed first in Regional skills USA automotive technician. I worked at Healey Mitsubishi, Goshen Automotive, and currently Elite Autoworks NY. I also go to Pennsylvania College of Technology for automotive technology with a minor in after market performance.

The car started as a relatively stock 1999 Rally Blue GM6 with 78614miles. Stock everything besides a Borla cat back. Put a lot of work into it for about a year and that's when I got my current phone so that's when the pictures start.

Drove the car everyday to and from school and work. Then I began fixing the OEM drivetrain one part at a time, while dailying it as much as possible. Replaced full with a Tsudo, clutch, slave cyl, master cyl, brakes, tires, radio, shifter bushings, intake, etc.

MOMO WRX wheel

Took a few trips up Bear Mtn.

Put about 12000 miles on it.

Once I finally got it all running right, no CEL, no issues, I drove it for about 9 months just oil changes, washes, and small bits and pieces. And I drove the car hard, a lot. I loved the thing. Got my fair share of harassment from the 5.0 about my exhaust, and raced a bunch of cars for no reason, went out for every drop of snow... because I was a jackass, like most seniors in high school with loud ass Subaru's.

Until the last day of school. Being the dumb ass that I am, I decided it would be smart to try some dry pavement donuts in the teacher parking lot during lunch. Bye, bye timing belt. Snapped right in half, this is where the swap began.

I started like most people with countless hours of research. I decided on a USDM EJ205 out of a bugeye for the cost, accessability, and room to grow on a limited budget (college kid problems:gaga:).

I was able to source and fully functional engine, transmission, differential, driveshaft, and extras from a 2002 wrx wagon that was getting a full JDM EJ207/4.444 swap.

For an unbeatable price as well. So obviosly I hopped right on it. Went back down the next weekend with my moms Toyota Highlander to pick everything up (should've took the truck lol).

Once the motor was home... Parents weren't too happy :eek:rly:

A lot of other parts too.

I quickly began accessing what it needed. Ended up doing some gaskets and cleaning. Valve cover, tgv to heads, manifold to tgv, and fuel injector seals. Also did spark plugs, NGK Iridium.

Checked timing belt, which had been recently done and decided to save the money for any other necessary expenses.

White Manifold swap:

WRX ECU and JDM GC8 Boost Gauge rated in BAR

Started taking it apart in the driveway. Got off intake, starter, and unplugged the wiring harness from the engine.

Then I got my car over to the shop I work at, Elite Autoworks NY. Bless my boss for giving me full access!!!

Started tearing it apart. Trying to get as much done as possible before I had to go to school. Took plenty of picture to reference and marked things as needed!!! Very important when trying to reassemble everything

Pulled the EJ251

Brought the WRX drivetrain over from my house.

My boss was happy to see it.

Finished disconnecting everything in the engine bay.

Did the trans swap on the lift. Undercoated the whole underbody when transmission and differential where out of the car. Notice my brother being useless in the bachground. Smoking hookah doing nothing.

Cleaned up pieces as I went along;

New diff cover (replaced seal as well).

Cleaned up the second intercooler (new bov gasket).

Tore the dash apart to pull harness for merge... this is where my issues began, big issues.

I quickly realized that the dash had been pulled on my car before and a few wires had been messed with (nothing crazy). Still had oem motor and trans so I don't know why the dash was off but for whatever reason, there where wires wrapped around the dash beam instead of being ran properly.:confused:

Everything was wrapped around the steering column and dash beam.

Missing tilt steering wheel lever.

More dash removal.

Some wires ran through the dash beam.

After trying to fight with everything, unsuccessfully, I called a friend and asked if he could do the merge in the car. (PROBLEM) :wtf: Obviously, with the most confidence he agreed. So I got enough stuff out of the way for him to access what he needed to.

As he worked on the harness I began feeling confident that we were past most of the issues and spent some money treating her to some after market bits while installing the EJ205.
-Perrin turbo inlet (sucky fitment)
-Perrin short ram (love it)
-Mishimoto ancillary hose kit (love it as well)
-Access port (perfection in a box)
-Cobb EBCs (simple and functional, no complaints, good installation pieces).

Also examined the clutch, flywheel, pressure plate, etc. Nothing was broken, clutch was new but used so I replaced the disc, and resurfaced the flywheel
-ACT Stage 2 (haven't driven with it yet)

Got the motor all in. Nice color combos I think. Really happy with it all.

New wrx slave cylinder and lines needed. Both from the WRX.

Custom shorty down pipe fitted to a modified Tsudo rs cat back. Also did Perrin hanger front to back. This is only temporary, car will be getting a full 3in. straight pipe to dual blast pipes!!:drunk:

By this point I had to go out and be an adult, starting college:cool:. So I had to leave the Subie behind while the harness was getting finished.

Came back to weeks later, harness was done, dash ready to go on.

Put it all back together (bad idea). Especially since the harness looked like this:

Buttoning up the EJ205.

Test fitting new belt for A/C and Power steering delete.

All back together.

Connected a battery and jump pack.......

Turned it over, cranking good, no start. :facepalm:

I tested for spark, compression, and leakage, all were good and well within spec.

So I turned to fuel. Had 93octane in the tank (1/2 tank or so). Pump turned on, had pressure at the rail, nothing past the injectors. Checked with noid lights and I wasn't getting any signal.

Started chasing everything down. Had continuity from all the injectors to the ecu connectors. They all had 12v koeo. But the ecu wasn't sending a ground signal to the injectors. No pule = no fuel = no start. Traced it back to what seemed like a bad ecu. Luckily I was able to get one that weekend. Swapped it it.... Same issue.

Now is where I really got lost, and spent a lot of time chasing down issues until I resorted to the basics. :bonk: I sat down and thought, after 2 months of chasing wires, what could cause the ecu to stop sending signals to the injectors. Two bad ecu's was unlikely so I put that at the bottom of the list. Then I plugged in the snap-on ethos and a live data test with the engine off.

I noticed A LOT of issues. Every single engine sensor was reading the default reading. ect was at -40, iat was at -40, tps was at 100%, tgv open, etc. Meaning that they all had an open in either power (5v) or signal to the ecu. I quickly found my issue. None of the sensors where ran to power or ground. Which is unbelievable wince you don't even need to touch any of them for the merge. But I guess my friend just wanted to cut **** since they were all sliced. :devil: Obviously we don't talk anymore.

That little blue wire that doesn't go to anything is supposed to be the ground for a majority of the engine sensors.

I used a power probe to feed 5v to those sensors, and grounded them temporarily, and she started right up. Ran smooth!

So now the search for a new wrx harness began. I could've fixed the connections myself but I was not happy with the rest of the harness, nor did I trust any of it, so I decided to redo everything properly.

Got the wrx harness easily, no issues. But the rs was another thing. I looked for weeks without seeing a single one for sale.

**Notice I will have more detailed pictures from here on out since I didn't plan on writing this till this point.

Took a break from the Subie for a little while to work on my brothers car. I think it came out nice so I'll share it with you guys. 2012 TC with Accurair H3, D2 bags, and custom Avant Garde F230's.

Now back to fixing the Subie. Still couldn't find a usable RS harness for sale.

So I bought this... '01 RS Sedan POS. Has a good harness though, mudflaps, passenger fender is mint, winter wheels, and new suspension STI struts and spings. Picked it up for $200 so I can't complain.

Tore this **** apart withing two days. :banana:

Got the harness out and contacted iWire. If you are doing this swap just call them first. They have great customer service and you know your **** will be done right, the first time. It is well worth the money. They really are great and very helpful.

Shed is now filled with interior parts rather than parts for the swap.

So this is what I'm up to now. As I continue the build I will add more and keep trying to include everything. If I missed anything just mention it below and I will cover everything. Same if you want more detail, I want to help everyone and answer every question I can.

Just sent the harnesses out to iwire

Any suggestions on format are greatly appreciated as well since this is my first thread. :yapyap:

Hope you enjoy and appreciate it, :burnout:
_ Nick


3 Posts
Doing an identical build! I will be posting pictures in a separate thread to show the progress 🤙🏽
1 - 4 of 4 Posts