Subaru Impreza GC8 & RS Forum & Community banner
1 - 8 of 8 Posts

·
Registered
'98 2.5RS
Joined
·
5 Posts
Discussion Starter · #1 ·
Hi all.

We got the new motor (still a 96-99 EJ25D) in.
So far:

- It cranks, timing is correct.

- Spark is present.

- Fuel is getting to the rail.

The camshaft position sensor is a known-good item. The crank position sensor is brand new. Fuel injectors are also known-good items.

Essentially, everything is functioning properly, except for the injectors.
I've perused the internet for a good wiring diagram for an EJ25D, but only single-cam cars are covered.

What else runs on the same circuit as the fuel injectors?
Any help is greatly appreciated.
 

·
Registered
Green 97 OBS
Joined
·
1,840 Posts
Can you check CELs? Do you know you are not getting fuel in the cylinder?

The fuel injection circuits should be essentially the same as any other subaru. The ecu pins may be different, the plugs may be different but the design should be the same. The #2 and #4 injectors both share a ground as do the #1 and #3. They are individually triggered by a direct signal from the ECU, each have a dedicated signal wire from the ECU to the injector. There isn't any fuses or anything else between the ecu and injectors however.
 

·
'MURRICA!
Hybrid Camry
Joined
·
5,700 Posts
Are you certain that BOTH the crank and cam sprockets have the same number and location of teeth as your stock motor?

Also, try putting the connectors for the injectors on backwards. Subaru changed styles somewhere in the years, so you might have to plug them in backwards (need to trim off the tab on the side and they should plug right in). Try it with one, see if it works, then repeat if it does. If it doesn't work, no harm no foul.
 

·
Registered
1995 WRX 2015 F150
Joined
·
1,886 Posts
How are they know good? How long did they sit around? They stick shut when they sit.

One wire on at the injector is 12+ whenever the key is on. The ECU grounds the other to fire the injectors. Connect a test light to the both and see if it flashes when you crank it.
 

·
Registered
'98 2.5RS
Joined
·
5 Posts
Discussion Starter · #5 ·
Can you check CELs? Do you know you are not getting fuel in the cylinder?

The fuel injection circuits should be essentially the same as any other subaru. The ecu pins may be different, the plugs may be different but the design should be the same. The #2 and #4 injectors both share a ground as do the #1 and #3. They are individually triggered by a direct signal from the ECU, each have a dedicated signal wire from the ECU to the injector. There isn't any fuses or anything else between the ecu and injectors however.
No code reader here. I'm positive I'm not getting fuel in the combustion chamber - I unbolted and lifted up the rail. No fuel while cranking.

Are you certain that BOTH the crank and cam sprockets have the same number and location of teeth as your stock motor?

Also, try putting the connectors for the injectors on backwards. Subaru changed styles somewhere in the years, so you might have to plug them in backwards (need to trim off the tab on the side and they should plug right in). Try it with one, see if it works, then repeat if it does. If it doesn't work, no harm no foul.
Sprockets were matched up while rebuilding the new motor. They're identical.

This is the same harness and set of injectors that worked just fine when I pulled it into the driveway less than a day before trying to start on the new setup. Something happened as everything got swapped over. Could the ECU have shorted? I plugged it in after the entire harness was connected and all grounds were secured.

How are they know good? How long did they sit around? They stick shut when they sit.

One wire on at the injector is 12+ whenever the key is on. The ECU grounds the other to fire the injectors. Connect a test light to the both and see if it flashes when you crank it.
They're known-good because they worked in the car less than twelve hours prior to trying to start it.

I'll go over the injectors with a test light later today. I'll report back with results. Thanks guys.
 

·
Registered
'98 2.5RS
Joined
·
5 Posts
Discussion Starter · #6 ·
We tested the injectors; no pulse at the connectors.

I'm going to jump power to the injectors via the ECU connector, then ground the pins that ground the corresponding injectors. This should fire them, so hopefully we can eliminate the ECU as a possibility.
 

·
Registered
Joined
·
1 Posts
I just did a 2.2 to a 2.5 swap in a 97 Impreza I ended up with the same exact resultsfuel pressure to the fuel filter and spark,it would start with starting fluidbut would not start on its own.It turns out it was just the fuel supply and return was swapped.I spent a day and a half tracing wires and sensors checking fuel injectors and all sorts of other things turns out I had my fuel supplyon the fuel pressure regulator side and the return on the fuel rail side if anybody else comes across this old post you could try this good luck all
 
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top