legacycentral bbs

This is really weird. I had a major drop in fuel economy so I was doing some diagnostics, I put the Brat into D-check mode, did a test drive and it comes back with codes 24,33,51 and 61

I fixed 33 and 51, now I've got 24 and 61

I'm going to try and fix the idle air valve this weekend... but what the heck is code 61?

The only reference to it I can find anywhere is from some early Imprezas, but this engine, ECU and harness came out of a 91 Legacy.

Any thoughts?

Hmmm, that's very strange....yeah I've never run across a code 61 before. If you clear the ECU memory and do d-check again, do the same codes come back?

I can't clear the codes. I tried disconnecting the battery for three days, pulling the fuse and removing the ecu completely from the car. nada.

the proper way of clearing the codes by connecting both connectors doesn't seem to work, but I think you need to take it for a test drive and get the all clear before you can clear them that way, right?

Anyone ever had the idle circuit in the ECU fail?

I can control the IAC manually by grounding the pins after disconnecting them from the ECU, but the ECU won't control it itself. It just keeps it full closed.

Yes you need to drive the car with both connectors connected to clear the codes.

The ECU would keep the IAC valve closed if the idle is too high and it's trying to reduce it.


Why don't we take a step back here, what symptoms and issues are you experiencing?

Well I've always had idle problems, but I've just ignored them. Recently my fuel economy took a huge dump do and started getting hesitation on acceleration. The problem is I've got about twenty codes stored from when I was trying to get the swap running initially, and I can't clear them so I can't figure out what's actually current. I need to fix the idle problem before I can clear the codes it seems.

When I've run across codes that won't clear it is either related to two things, there is a code for the canister purge solenoid and/or the ECU thinks it is a "california" spec car.

What is the ECU part #?

Is there a wire going to connector B56, pin 11 of the ECU?

http://www.main.experiencetherave.com/s ... _page1.jpg


Do you have a code 35 stored and/or do you have the canister purge solenoid installed?

There is a code 35 stored from when I was trying to get the swap running, but there isn't a current one when I put it in d-check mode. I have a purge solenoid hooked into the wiring but its not actually hooked up to anything, but that shouldn't matter, AFAIK it only goes off the resistance of the solenoid coil.

The codes I have stored are 11,12,13,14,15,16,17,21,22,23,24,31,33,35,41,42,49,51

I only get the code 61 in d-check mode, it doesn't get stored.

I'll have to double check the ECU part number, I don't remember if that region pin was grounded or open but the wiring harness came from a canadian car, so it should be ok.
It's a hitachi ECU.

I haven't had the code 61 come back again and I think I've figured out my idle problem

Looks like the 91 manual trans car is supposed to come with a different idle control valve than what I have, a 2 pin version.

Actually now I'm thinking that my whole intake manifold is more likely off a 92. So rather than finding a 91 IAC, I'm probably better off trying a 92 ECU.... although then I'll also need a jecs maf... hmmm...

Yeah, I'd go for the newer ECU. You'll need to run a switched 12v wire to the center pin of the 3-pin IAC valve if it's not there.

http://www.main.experiencetherave.com/s ... C_diag.jpg

Additionally, the AT/MT identifier pin is wired backwards on the 92 ECU compared to the 90-91 ECU's. I talk about it here in my swap write-up

http://www.surrealmirage.com/subaru/swa ... l.html#ecu

oh my god.

It idles.
It gets 35mpg.
No more codes.

I really wish I'd dug into this a year ago. I would have saved so much money in gas...

It was the ECU?

Wrong ECU for the intake manifold. The manifold must have been off a 92-94 car. It's got the rotary valve IACV and the red injectors.

Snagged a junkyard 93 ECU and a JECS maf, and its running like a champ now.

Good to hear!

Your vehicle failed because of a fuel cap!?!

haha yea.... my old fuel tank rotted out and I replaced it with an aluminum fuel cell, but one of the screws for the fuel level sender leaks a tiny bit, and if the tank gets pressurized it leaks a lot. so I took the seal out of the gas cap until I can drop the tank to repair it properly.

It doesn't matter though, I got a new job and I'm moving in 2 weeks to a place without emissions testing, but my insurance expires in 2 days so I had to do it, even though I failed I can still get another 3 months of insurance. Then when I move I reinsure it in the new zone and thats the end of it.

The shit we do the pass inspections

I had pretty much bald tires on the Impreza and needed to get it inspected. I swapped on the set of WRX tires so it would pass and put the bald tires back on when I got home. I finally did get new tires last week, but needed a little more time between when my inspection was due and when I could get tires.

Splinter wrote:haha yea.... my old fuel tank rotted out and I replaced it with an aluminum fuel cell, but one of the screws for the fuel level sender leaks a tiny bit, and if the tank gets pressurized it leaks a lot. so I took the seal out of the gas cap until I can drop the tank to repair it properly.

It doesn't matter though, I got a new job and I'm moving in 2 weeks to a place without emissions testing, but my insurance expires in 2 days so I had to do it, even though I failed I can still get another 3 months of insurance. Then when I move I reinsure it in the new zone and thats the end of it.

I'm also thinking of replacing my crumpled gas tank with a fuel cell. What kind of aluminum fuel cell did you get? I've found some online, but its not clear if any cell will do, or if there's something special needed for a Subaru.