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Old 12-11-2003, 09:38 PM   #1
Murray
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Join Date: Oct 2001
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Location: ghettoville, PA
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2009 Gray
Legacy 2.5i

Default MY99 EJ25 into MY97 EJ22..idle control help

anyone out there other than me run into the problem with the incompatability of the 6-wire MY99 idle control motor on the 97 3wire ECU?

im currently using a IAC motor oout of a old Saab 900, its a 3 wire motor, which has double the internal resistance of the stock one..which seems to cause the motor to idle high, then low, and occasionally stall out.
im wondering if theres a better IAC motor i could use to better serve the ECU's demands.
engine has been running this way for about a year now.

my curent setup is a large hose from the intake to the IAC motor, then another large hose run from the IAC to the throttlebody, where the stock 2.5's IACmotor went, its kind ahalf-ass glue'd/epoxy'd/sealed into place.. then i blocked off the stock holes thru the T.B.
it works..but like i said, its a little slow reacting.

the old 1.8 had a 3 wire IAC motor...in the same basic shape of the EJ25 6wire motor.. anyone know if this will work?
i know the current one on my car is Pulse width modulated for fine-tune controlling of it...but i thought i heard the 1.8's wasnt P.W.M. controlled..

any help on this would be appreciated.

Murray
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Old 12-12-2003, 12:44 PM   #2
rob
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It tastes like burning

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Likely the one from the 1.8 is the same type as the original 2.2. The one on the 2.5 is a completely different type of unit; stepper motor vs PWM bi-polar valve. Hopefully you haven't burned anyting inside the ECU trying to run the SAAB part.
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Old 10-20-2004, 04:29 PM   #3
Hondaslayer
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Bump

We currently have this car in our shop, any thoughts?
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Old 10-20-2004, 06:24 PM   #4
Murray
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last i heard was ECU troubles... which i didnt have when i had the car.
i DID however have carbon tracking across the ignition coil to the one grounding bolt, which on cooler, wet mornings would prevent Cyl 1 from firing..

the idle fix is easy.. do what RalliSpec did with a Ver. 6 swap (this is where my idea came from)

take the throttle body, weld in a piece of metal conduit about an inch and a half long, there should be a size pipe that will almost exactly fill the hole in the TB(DONT BLOCK THE HOLE LEADING DOWN TO THE INTAKE MANIFOLD!)
on this hose, place a large vacuum-proof hose and route that back to the Bosche IAC motor... from the IAC's inlet back to the intake tube.

i never used the conduit... never had time to pull my TB off to measure and weld and all... i jsut glue'd in the vac. tube and then placed "helper tape" to hold it in place... kinda rigged, i know, but while it was working..i figure i shouldnt remove it.

please make sure hte IAC has the 2 ground wires on the correct sides..it WILL NOT WORK with them reversed.. i really wish i had taken the extra 15 minutes to find a true male and female connector to use instead of the cheap crimping Male and female terminals (soldered on...of course)


this sucks... i miss that car so much now. if i could only afford 2 cars....
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Old 05-13-2005, 12:23 PM   #5
WRX-ECE
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Doing the same swap as Murray I found a better way to fix the IAC issues.

I used a throttle body from a 93 1.8, although all of the 1.8s I looked at had the same design. They have the IAC valve on the TB like the 2.5 but it is a compatible three wire.

All we had to do was make a custom gasket to seal up the hole in the 2.5 intake manfold where the air for the IAC would go through. In the 1.8 the air flows is conatained completely in the TB. Was easy, bought a roll of gasket material from autozone.

Only three issues with fitment:
1) mentioned above, the custom gasket
2) the throttle pos. sensor has a diff plug, so we needed to splice on the correct plug. Shouldn't be a problem if you use a TB from same year as your 2.2
3) Throttle cables don't quite work out. Needed to add about 1/2+" of spacing to the trottle cable bracket from the 2.5 to get WOT. Also the hole for the cable is too small on the 93 TB, so we had to drill it out. Again, shouldn't be an issue if you use the same year TB.

Other differences:
1)The 1.8 TB has a coolant temp controlled idle adjustment, we left disconnected
2) the 1.8 TB has a couple vacume lines on it. We capped them off.

PS - the TB cost me $23 with sensors at the junk yard. I got a Saab IAC too for $5 just in case.

PSS - the 1.8 IAC will NOT fit the 2.5 TB, close, but different. Also the TPS is different between the 93 1.8 and 96 2.2, but the 96 2.2 and the 99 2.5 are the same.
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Old 05-13-2005, 12:27 PM   #6
WRX-ECE
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Also, I'm seeing the high then low idle issue, but only at startup. Goes to about 2K then dips to <500 then idles great after that. Rock solid between 750 and 1K

Jeremy
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Old 11-09-2010, 02:50 PM   #7
saab90089
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I know this thread is VERY old but I wanted to add some additional information to this thread.

I replaced my 1997 2.2ltr engine with a 1999 2.2ltr engine. This presents many of the same electrical problems as the 2.2 to 2.5 swap.

I too used this '1.8 throttle body trick' on my setup. So I used the wiring harness from my 1997 transplanted to the 1999 (changed connectors for the fuel injectors) and used a 1.8ltr throttle body. The Idle controller from the 1997 harness plugged into the 1.8 t-body. The TPS sensor connector from the 1997 would not plug in though, I had to grab a connector from the 1999 harness and cut/soldier to the 1997 harness.

End result everything worked fine. No CEL's and the car idles fine. Once warm it idles low (300-400RPM) but nothing too bad.

Ian
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Old 11-09-2010, 03:50 PM   #8
Storm
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Good to know!

Thanks for the update, as I've seen this question a few times now. I never got around to putting my EJ18 TB on my car to verify this would work, even though I had a feeling it should.

Jay
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Old 11-09-2010, 07:47 PM   #9
ballitch
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When I swapped my current motor I MacGyver'd my IAC valve.

I remote mounted it on the firewall so I could plumb it into the intake. This required the help of a piece of scrap 1/2'' aluminum plate drilled for the stock bolt pattern as the IAC valve. Drilled and tapped the plate for a 90* 1'' pipe fitting to get idle air plumbed into the intake tract. I then drilled and tapped a hole in my EJ25 sohc intake manifold, threaded for a brass fitting that you can attach a 1'' ID vacuum hose to.

Ran extended coolant lines from the stock location, unwrapped stock wire loom to get more wire and voila, problem solved. Maybe I should take a picture....



~Josh~
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