janas19

Nah, engine should be fine. One thing you might try, disconnect the vacuum line from the fuel pressure regulator and open the throttle. If the problem changes, then you were likely getting enough fuel pressure. If the problem stays the same as before, then likely the bad pump.

Might have a bad fuel pump. Sounds like a bad fuel pump imo

Nice! Gives me hope I might find a good deal on my hunt

Yeah heckuva score. Where did you buy it?

If the manual transmission sensors on the 93-95MY Imprezas can all be threaded/spliced to the 99-02 three plug harness, that wraps things up for me. Basically, all I need to know is that I don't have to do a tranny/gearbox/clutch swap. I intend to keep the drivetrain exactly the same, don't want to spend a dime on it for 165HP. Everything on the engine side will match up with the full harness swap. The headlights/taillights may be a PITA but should work out. Dash, cluster, and ignition switch will be fully swapped from 99+. Dash back is pretty irrelevant. Front harness, fan switch, and fuseboxes may be a PITA but I think it will work out. That's pretty much all I need to know, think that just about wraps things up for me here. Unless anyone else wants to chime in then I'm moving forward from the planning stage to the acquisition stage of the project. A huge thank you for all the helpful info.

Texan, I disagree. Cook your brakes before cooking your engine.

Alright, I have been straightened out thanks to matt167 and Numbchux. Here's the revised plan: 93-95 Impreza wagon 5MT EJ251 longblock 3 plug ECU harness and dash from 99-02 Forester 99 Forester ECU with MAF My unknown variable at this point is the 93-95 5MT tranny and gearbox. Is it compatible with the 3 plug JECS ECU? Here are the connector terminals for the 93-95 which I have been able to find: Backup light Neutral switch Vehicle speed sensor (VSS) Starter interlock Are the 99 harness connectors plug N play? Doubtful. Two possible options: 99 sensors plugging into 93-95 tranny. Or splicing the 93-95 connectors to the 99 harness. Anybody have an answer or should I look to the junkyard for answers?

OK, wow. I really am actually an idiot. I just realized that the 99-02 cars are SOHC. Why was I thinking DOHC? I guess I thought JECS ECU in 99-02 meant different ECU which meant different heads. Nope. Same heads, different ECU. OK, I get it now. EJ25D = 96-99, one plug ECU, DOHC. EJ251 = 99-04, with two different 3 plug ECUs. 99 Forester has the 3 plug ECU with MAF. 99-02 are MAP. Matt167 is suggesting the 99 Forester ECU and SOHC heads are plug N play. Man, I really apologize for my own mistakes and stupidity. Thank you Matt167 and Numbchux for straightening me out.

Documentation on 95 L coupe to 98-01 dash conversion: http://www.rs25.com/forums/f145/113716-rhd5280s-1995-l-coupe-2006-sti-swap-widebody-gtx3076r-now-dry-sump-8.html Looks like 4 modifications are required, 3 can be done with drills and grinders. For the last one which requires welding I am going to cold weld the dash mounting tabs using JB Weld, should be adequate.

Working link to the full 99-01 Impreza wiring diagrams PDF for reference: http://www.mediafire.com/file/ndg4nnm5tvz/Subaru_Impreza_wiring_diagram.pdf. 65 pages of wiring goodness mmmm. Going to be parsing through all this next week.

Thanks Matt. The idea is to go full Forester harness and dash, since 2.5 Imprezas are so hard to find. Nice tip. I'll definitely pick up the DOHC heads off the 99-00 to match IACV, but like I said, it's going on top of the 251 shortblock. Too risky to use the 25D bottom end when junkyard is the source... Are you aware if the 93-95MY 5MT switches match up to the 99-02 Forester harness? That's my primary concern. Thanks.

I found something interesting at the junkyard. There's a 98 Legacy hybrid. It has the DOHC, Phase II block, and a single plug ECU.

Took a trip to the junkyard today. That was enough to dispel any illusions. This will be a helluva job. I'm estimating 1-2 months, minimum, for a full OBI to OBD II harness conversion on the 93-95MY. First thing is to map and plan everything out. First, I have to do a full walkthrough on the OBD II vehicle and identify every necessary electronic signal. Then I need to get the Impreza wiring diagrams and map out each signal I have to retain. Finally, I'll have to strip both vehicles and find the terminals/plugs of all signals, fuseboxes, relays, and connectors. It will be loads of fun, I'm sure! That's only the beginning. This conversion is going to take a couple of months, at least.

Mind elaborating on that? I'm using the 25D mani and harness... Why would TB and idle be an issue? Also, it seems to me that the Impreza dash/harness would be easier? The Forester has a different body so the harness and dash dimensions won't match up as easily? The 2.5RS cluster is ugly as sin. I'd rather using anything else than that cheap white monstrosity. I'm going to go to the big junkyard 40 miles from home today and look at every Subaru. I'll be taking notes and preparing for the conversion. No one here is selling a hatch. I might have to go to UT or TX...

OK, this is what I'm going to do: Junkyard EJ251 shortblock EJ25D heads, 04-06 STi MLS gaskets 99-02 2.5RS harness, cluster, and ECU 93-95 GF5 wagon 5MT Any mismatches or big mistakes here? I'll figure out the small stuff myself, but this will be the plan going forward.

Thanks. Sorry if I'm asking too many questions, the Subaru ECUs are pretty new to me. And thank you so much for sharing your knowledge. I'm thinking I'll buy the hatch first and start slowly chipping away at the harness conversion first, because that's going to take the most time. Ideally, I want to make a harness which has the 3 plug connector for the JECS ECU, but can be made to fit either the EJ25D OR the EJ251 on the engine side. I don't even know if that's possible, but that would be the most flexible and sensible solution. The big issue seems to be the MAF/MAP sensor differences. I believe everything else between the two is pretty similar and can be easily modded.

Well the other thread was about swapping a Phase II EJ251 engine into a 95-98 Legacy. I decided to ditch the Legacy chassis and go with the Impreza hatch instead. And I'm looking at a full EJ25D-1 conversion, wire harness, engine, dash and all. Seemed like it warranted a new thread. Is that alright? Not trying to break any rules or piss anybody off :-)

I like that. I want to learn more. I'm going to read over the website. So EJ251 MAF is best, then MAP second? Are the MAF ECUs only in 99MY Impreza?

Alright, guess it's best to go EJ25D or EJ251. If I get a 93-95 hatch, I'm going to do a full OBD-II harness conversion with knock sensor and full mani swap. I can pull the harness off a rust bucket at U-Pull for $40. I'm estimating around 40-50 man hours for a complete conversion, my first time. Do you have any recommendation on the best MY ECU between the EJ25D and EJ251 heads? 90% of my driving is done under 4000 RPM, so my goal is torque and complete fuel efficiency.

Yes you're right. I don't need the AVLS, I don't have to have it. I will still look for the 04-06 EJ253. Better block and intake manifold, lower mileage = less ring/cylinder wear = longer lasting better engine. I need the 04-06 instrument cluster, full harness, and ECU. What about the steering column? I don't know which dashboard is gonna work. I'm going to tear down the interior to the bare shell and map out each wire on the harness. I'll pay $400-500 for the hatch, and $700-800 for the EJ253 longblock. Might take me a month, even two months to find them for the low. Have to drive to Denver. If I can get a good EJ251 from the junkyard for $300 I'll probably go that route. Problem is I'm 40 miles away and can't drive their everyday to look, plus I have to buy a compression tester for $50

What do you mean?

Highway MPG is very important so the 3.3L is out of the question. If I'm going six cylinders I'd rather have a pickup truck. True, but I'm using a different approach. The goal is cheap and speedy, so the lighter the better. This official Curb Weight thread over at NASIOC is my bible. Most important is simple availability and price. I'm looking to spend no more than $500 on the shell which likely means non-RS. Hence the necessity of swapping.

Allow me to skip the fluff and get right to the nitty gritty. I'm actually seriously considering doing this conversion and all the man hours and work it would require. I want your highly valued feedback and don't pull your punches, give it to me straight. I want to know everything I can about an EJ251/EJ253 conversion. The reason is I'm looking for broke-down Impreza hatchbacks from '93 and up. If I find a '93-'95 MY I'm planning on a full OBD-II harness conversion. Since the full harness conversion is on the table anyway, why not look at the EJ253 with AVLS? Looking for your feedback and thoughts.

So I didn't know this but there are factory hybrids. The 98 2.5RS has the Phase II block and DOHC heads. Rumor is the 98-99 Outbacks also have the hybrid engine: Can anyone confirm?

Bahahaha. Build a hybrid in the junkyard ground? I love it! LOL Dude, you get a gold star. This is genius!