DIY - 1990-1994 1/2 EJ22 Subaru Conversion with stock ECU

[Buggin_74]

I thought disconnecting the battery cleared the codes?

It does but how long it takes depends on the memory battery condition.

My current ECU clears codes in about 2 hours as the battery is obviously stuffed but my original ECU took more than 2 days before the codes were gone.

[TimS]

Regardless, diagnostic mode (green plug) only displays active codes not stored codes.

[Thesatelliteguy]

I had the battery disconnected over night. IDK if i could go a few days with out driving it now.

I checked the voltage at the injector. 11.83 volts with the key in the "on" position.
Is that sufficient?

[TimS]

Yes that is good. Hmm... I would double check continuity with the wiring. It could also be an intermittent connection. Does it run smooth?

[Thesatelliteguy]

It runs smooth as far as i can tell. The radiator is leaking water so i cant really take it out on a nice long drive. But i did putt around the neighborhood and it seems to be smooth.
I ordered the radiator yesterday and it should be here tomorrow. It couldnt get here fast enough either! God i want to cruise around town sooo bad!

[TimS]

The only other thing I can think of... OEM is to have 12v to injectors permanently. I've wired up all of my conversions with the injectors powered by the ignition switch to prevent the constant corrosion. I've never had an problem or error code, but it might be worth trying to provide 12v to the yellow wire that goes to the engine plug for the injectors before the computer is turned on. It's possible that the 1990 computer doesn't like not seeing the voltage immediately? It's a stretch, but the only other thing I can think of other than defective wiring, loose connection, or bad injector. Where it's running okay, I'd not think injector.

Let me know what you find, and thanks for reporting your results.

[Thesatelliteguy]

I'll keep you posted

[Thesatelliteguy]

The injector #3 code went away.
Now its code 22, the knock sensor, but only in the stored memory. When i run a diagnostic test, the check engine light stays on.
What does the constant light mean with the green diagnostic plugs connected?

How do i check my knock sensor?

Also, the engine will intermittently studder, like its running out of gas. Then it will come back to life like nothing happened. Any idea about that?

I kind of answered my previous question about the temp sensor ohm range. Using the stock sensor for the VDO gauge seems to be right on track with the actual temp. I used a lazer temp gun and took a reading where the sensor is located. its seems to be the exact same.

[TimS]

Knock sensor is picking up the engine studder. That's means it's working. Light doesn't flash in diagnostic mode because no code is active.

I'm still thinking intermittent wiring problem. Probably to do with the engine plugs. But you know what it looks like, I don't. Try wiggling the plugs with the engine running and see if you can reproduce the studering and see where it's caused.

The active injector code in diag mode means there was something wrong. If you didn't fix anything, it's likely the same thing. Inj #3.

[Thesatelliteguy]

Also, its idling kind of high when its warmed up. Its about 1200 rpms. I remember reading a 700 rpm is appropriate.

[TimS]

1200 when warm? As in after it's driven for a while? Do your fans come on okay? Radiator get hot?

[Thesatelliteguy]

The temp was about 180ish. Rad fans were on, rad was hot.
However, I just got back from a drive and it got up to 200* F, then it was idling around 700. Also, about half way through the drive I found that the parking brake wire (coming off the computer) was not grounded when it was supposed to be. I touched it to ground and the idle went down. So i think i have solved that problem.

Now the computer is throwing another code though.
24 this time, idle control circuit.
It didnt have this code before the drive.

Could the high idle be the reason for the code?

[TimS]

Try to reset and see. Does the throttle cable go slack and let the butterfly close all the way?

[Thesatelliteguy]

Yes, the throttle cable has slack.
Ok, ill unplug it tonight and see what happens tomorrow.

[danielzink]

Silly question....but is there a guide like this anywhere....that deals with the later engines ?

In my particular area (Michigan, Ohio, Indiana).....90 through 94 complete cars are like hens teeth....

On the other hand....I can find 95-99's......$800...$900....ish...etc...

Interference motor be damned.......I'm just looking for a "strip down - bolt in" for my buggy.......

Either that...or I blow my wad on a type 4 build......




Dan