Welcome to the North American Subaru Impreza Owners Club Tuesday March 19, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Service & Maintenance

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 02-23-2004, 01:53 PM   #1
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default Idle air control valve circuit

Yet another problem with my 1995 impreza L. 5 speed AWD 1.8l

Something is draining my battery. The other day the car wouldnt start (fast clicking from the starter solinoid). Popped the hood and heard a high frequency electrical noise like a transformer. I traced it to the Idle air control solinoid. I unplugged it and it stopped. Then car also started at that point. With the idle air control valve disconnected I checked voltage with a multimeter across PIN # 2 and PIN# 3 on the wiring harness end. I was getting alittle over 12V with the car turned off and the key in my hand.

My question is, is this normal? should I be getting power to the IAC when the car is off? It doesnt seem right.

Also, what controls this circuit? Is there a relay somewhere that can be stuck? I have the wiring portion for the engine harness and then I have the copy of the ECU pinouts but I dont have the electrical diagrams for in between So I cannot see components in between. Any ideas?

Thanks a ton for any ideas you may have...
* Registered users of the site do not see these ads.

Last edited by Hawk296; 02-23-2004 at 04:47 PM.
Hawk296 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 02-23-2004, 04:48 PM   #2
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

any ideas?
Hawk296 is offline   Reply With Quote
Old 02-23-2004, 09:08 PM   #3
avk
Scooby Specialist
 
Member#: 17252
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: NJ
Vehicle:
'06 WX8
59E

Default

There shouldn't be battery voltage at IAC with the key off. EFI devices are powered through the main relay, and the grounds are controlled by ECU (someone please correct if this is wrong). Are you sure nothing gnawed on the bulkhead harness? That might explain it all, including ABS. Anyway, you probably need wiring diagrams.
avk is offline   Reply With Quote
Old 02-23-2004, 11:17 PM   #4
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

Yeah thats pretty much what I was thinking. Hmm Ill look closer at the harness tomarrow. There are some really strange people in my apartment complex, maybe they decided to snack on my wiring haha.

I definatly think my misfiring/stalling problem is related and also considered my ABS as well. We will see.

I just need to get the car to MI on fri...

Thank you so much for replies!
Hawk296 is offline   Reply With Quote
Old 02-23-2004, 11:26 PM   #5
Castle4kq
Scooby Newbie
 
Member#: 54670
Join Date: Feb 2004
Default

#1 Fix all

1) splash gasoline throughout and under vehicle

2) apply spark for ignition.

3) call insurance
Castle4kq is offline   Reply With Quote
Old 02-24-2004, 12:23 AM   #6
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

HAHA! I am so almost at that point right now....
Hawk296 is offline   Reply With Quote
Old 02-26-2004, 10:27 PM   #7
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH
Vehicle:
2012 Impreza

Default

I had trouble with my sensors and solenoids being powered when the car was off too. I got in the habit of disconnecting my battery when parking my car.

I did eventually trace it to a bad ignition relay. I got a replacement from subaruwrxparts.com, put it in, and all was well.

I do believe the IAC valve is powered directly from the ignition relay.

Apparently Subaru used to use better ignition relays. Loyale ignition relays have platinum contacts, so they don't wear out nearly as fast.
vrg3 is offline   Reply With Quote
Old 02-26-2004, 11:43 PM   #8
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

Thats crazy, thats exactly what I have been doing everytime i go somewhere, connect the battery, then disconnect when i get out. It just has to get me through tomarrow so i can make it back home.

Thanks for the info, I'm definatly going to check into the ignition relay. Where is that located in the car?
Hawk296 is offline   Reply With Quote
Old 02-26-2004, 11:48 PM   #9
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH
Vehicle:
2012 Impreza

Default

Assuming it's in the same place as in my Legacy, it's in a very annoying place.

It's mounted behind the driver side dash, way up high against the firewall. I was able to reach it by sitting cross-legged on the floor facing away from the car, and reaching up with my right hand. There's a cylindrical metal relay which is the fuel pump relay, and a brown rectangular one which is the ignition relay. The ignition relay is somehow snapped into its mounting bracket and I was never able to figure out how to get it off. I just disconnected the harness from it and mounted the new relay elsewhere with zipties.
vrg3 is offline   Reply With Quote
Old 02-26-2004, 11:53 PM   #10
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH
Vehicle:
2012 Impreza

Default

Actually, before I was able to source a new relay I did come up with a kinda cool workaround.

SBF-2 in the underhood fuse box was responsible for feeding power to the ignition relay's contacts. So, I stuck spade connectors into the fuse box and wired a relay in series with the fuse. Then I had the coil of that relay driven by the parking light wire. The end result was that power was cut to the whole engine management system whenever the parking lights were off. Since they cut off automatically when you turn the car off, that worked well. As a bonus, if I turned off the lights manually, the car wouldn't start -- an anti-theft device.
vrg3 is offline   Reply With Quote
Old 02-26-2004, 11:54 PM   #11
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

haha, so youre still carrying around a dead relay!? awesome.

Seriously though It probably is in a similar place seeing how subies are so alike. Ill check it out. It really sounds like this could be it. Its been driving me nuts. Thank you much.
Hawk296 is offline   Reply With Quote
Old 02-27-2004, 08:34 AM   #12
avk
Scooby Specialist
 
Member#: 17252
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: NJ
Vehicle:
'06 WX8
59E

Default

The ignition (a.k.a. main) relay is plugged into the harness that goes through the firewall. It's indeed brown and has two pairs of switching contacts, so spotting it shouldn't be very hard. But it's much easier if you remove the lower trim panel.
avk is offline   Reply With Quote
Old 02-27-2004, 02:00 PM   #13
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH
Vehicle:
2012 Impreza

Default

Hawk296 - Yup... The whole ordeal has now made my car slower due to added weight.

avk - It must be easier to see on GC/GFs than BC/BFs. On my car it was hard to see even with the trim removed. I ended up doing it by feel because I could never see it and touch it at the same time.
vrg3 is offline   Reply With Quote
Old 02-27-2004, 08:40 PM   #14
avk
Scooby Specialist
 
Member#: 17252
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: NJ
Vehicle:
'06 WX8
59E

Default

Yes, on 1st gen. Legacy it may be harder to work in the footwell because ECU is in the way, and on your (vrg3's) car likely the cruise control, which a '95 Impreza wouldn't have from the factory.
avk is offline   Reply With Quote
Old 03-06-2004, 02:59 AM   #15
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

ok so i have located the main relay. It is indeed getting stuck on but its not the relay. I bench tested the relay and it works fine. It also returns to its open position when the battery is disconnected and reattached. It stays this was until the key is turned and the ECU engergizes the relay again. THen once energized the main relay stays that way (with 12V running through the coil) when the key is off and removed.
There are two large 16 pin connecters that connect the engine harness to the main harness that goes through the firewall. One is grey and one is blue. If you disconnect one of these there and leave the otehr connected the relay works fine and switches on and off with the key. When both are connected the relay gets stuck on until its reset by removing power all together by disconnecting the battery cable. I have been chasing wires all day. This defys all logic and I am completly burned out from it.
Hawk296 is offline   Reply With Quote
Old 03-06-2004, 03:06 AM   #16
wagman01
Scooby Specialist
 
Member#: 3894
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: Royal Oak, MI
Vehicle:
2002 WRX Wagon
Battlewagon Black

Default

Quote:
Originally posted by Hawk296
ok so i have located the main relay. It is indeed getting stuck on but its not the relay. I bench tested the relay and it works fine. It also returns to its open position when the battery is disconnected and reattached. It stays this was until the key is turned and the ECU engergizes the relay again. THen once energized the main relay stays that way (with 12V running through the coil) when the key is off and removed.
There are two large 16 pin connecters that connect the engine harness to the main harness that goes through the firewall. One is grey and one is blue. If you disconnect one of these there and leave the otehr connected the relay works fine and switches on and off with the key. When both are connected the relay gets stuck on until its reset by removing power all together by disconnecting the battery cable. I have been chasing wires all day. This defys all logic and I am completly burned out from it.
I worked with Hawk296 for a few hours tonight on his car, and I want to add that we checked for shorts through the sensor side of the gray harness, using a continuity test on each pin. We originally thought we had found a short, but it turned out to be an injector that we had left plugged in.

I'm by no means an electronics wiz, but I do know my way around fairly well, and this has me completely stumped. The relay is switched on by 12v from the ECU (light green wire). We tried swapping out the ECU, and it did the same thing.

So we've basically eliminated a bad ECU, bad sensors, bad harness, bad relay.

Any other suggestions?
wagman01 is offline   Reply With Quote
Old 03-06-2004, 11:45 AM   #17
avk
Scooby Specialist
 
Member#: 17252
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: NJ
Vehicle:
'06 WX8
59E

Default

All that comes to mind, maybe the "cold" side of one of the two switched circuits somehow came in contact with the positive side of the coil inside the housing. Then the relay would become self-latching. Can you disconnect the relay and check for continuity between the pin that connects to light green/white, and the other pins? You should only have continuity across the coil.
avk is offline   Reply With Quote
Old 03-06-2004, 12:39 PM   #18
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

With the relay unplugged, there is no continuity between any of the pins ecept the the Light green wire that connects the ECU to the coil and the ground for the coil which is directly across from it. So there is no continuity except for across the coil.

with the relay powered to the closed position, there is continuity between the two pins that normally are connected to B+ and their respective pins. This to me indiactes that the relay is operating correctly with no internal shorts.

I also got a jumper wire and 12V and put 12V to the two pins that are normally hot from the battery and grounded the other two. Then added 12V to the coil to make it switch (thinking that once it was switching it was shorting internally to the coil keeping it powered) but as soon as I removed the 12V from the coil it disconnected and opened up.

So overall I tested the relay just about everyway i knew how and it passed all my tests. I even connected the relay to the harness via jumper wires one at a time and everything works fine UNTIL the dark green wire is attached. Everything but this green wire can be attached and it switches on and off fine. As soon as the dark green wire is attached it will switch on and get stuck on.

This dark green wire is the one that runs from the relay to the MAF and to power the injectors. That is what led me to try and disconnect that side of the engine harness from everything else discovering that once its disconnected it works. From there we disconnected every component and tested continuity as mentioned above.

I am going to take everything off, fab up a manifold, and switch to a carburator and distributer. haha.
Hawk296 is offline   Reply With Quote
Old 03-06-2004, 01:10 PM   #19
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH
Vehicle:
2012 Impreza

Default

Is the ECU's "ignition switch" pin getting voltage for some reason?
vrg3 is offline   Reply With Quote
Old 03-06-2004, 02:34 PM   #20
avk
Scooby Specialist
 
Member#: 17252
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: NJ
Vehicle:
'06 WX8
59E

Default

When applying 12V to the "hot" switched contacts with a jumper, why did you ground the other two? Can you test it w/o grounding? To positively exclude an internal short, there has to be 12V at the "cold" side. If I misunderstood, never mind.

Add: The green wire connects to ECU, too. So what happens when you unplug it looks like correct behavior. At this point I second vrg3's opinion.

Last edited by avk; 03-06-2004 at 10:08 PM.
avk is offline   Reply With Quote
Old 03-08-2004, 12:37 AM   #21
Hawk296
Scooby Specialist
 
Member#: 14555
Join Date: Jan 2002
Chapter/Region: MWSOC
Location: MI
Vehicle:
1995 Impreza L
Baja

Default

I had to head back to IA today so i didng get much time. But I did aquire a new main relay from another car. It is for sure a good relay but when in my car gets stuck on also. So I can now safetly rule out the relay and look deeper into the circuits it connects to and the ones that control it.

And youre right that green wire does go to the ECU also....

And last night I went back and Re-checked all my fuses (have done this already and all were good) But this time the 20A fuse for the "main fan" was blown. I replaced it and so far all is good on that end of things.
Hawk296 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
P0508 and the Idle Air Control Valve Chigliakus Service & Maintenance 11 01-30-2007 08:28 PM
Idle Air Control valve??? NavyRSt Normally Aspirated Powertrain 13 11-28-2006 06:37 AM
TX idle air control valve wanted styleandspeed Private 'Wanted' Classifieds 0 05-15-2004 01:16 PM
WRX Idle/Air control valve djerickd Private 'Wanted' Classifieds 11 12-02-2003 11:37 AM
idle air control valve, after a turbo mod mild_se7en Normally Aspirated with bolt-on Forced Induction Powertrain 1 08-10-2002 07:45 AM

All times are GMT -4. The time now is 04:15 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.