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afternoon guys, finally got my rebuild completed and back into the car. its turning over and sounds like its trying to start but stinks of petrol and i think its flooding after a few attempts at trying.
Rev C GTB Etune.
ive tried both a snapon verus and my laptop with the deplhi system and neither show any faults but show -40c for the IAT is that a default figure for a faulty sensor?
does the MAF house the IAT? from diagrams i can find..
Pin 55 Green Airflow meter +
Pin 124 Black Green Airflow meter Gnd
Pin 60 RedBlack sensor power source
leaves a Yellow and Blue wire into the MAF..
any other likely candidates or places to be checking?
As joe says above turbo models usually have the IAT located with the maf sensor.
JDM models do not always have the same wire colour coding as European/US models.
For anyone reading this thread "revC" by itself doesn't mean much unless you have a year or model code to go along with it (B10/ BC#/BF# : B11/BD#/BG# : B12/BE#/BH# etc. ) as revision code starts again from A for each model range.
As in a previous thread you state 3rd Gen, we are probably looking at a B12/BH# (as it's a wagon) of late 1999 to early 2001 vintage???
If your maf is 4 pin - no IAT; if it's 5 pin - IAT included.
The pin numbers you quote are pointless, without reference, as on Subaru diagrams they would be numbered 1-5
An example of a 5 pin maf and socket (different wire colours to those you quote)
Thanks for the reply. sorry for the lack of into, normally posting on a legacy page with the car as my avatar.
Its a BH5 GTB etune.
Ive been struggling to find any decent wiring diagrams so the pins i posted were off a diagram found on a single turbo conversion page. (listed as SCT_BH_Wiring.PDF Subaru Legacy BH5 rev A,B & C) and corresponds to pins from the 3 main plugs. Ive not had a chance to go digging to confirm they are all what they say they are but wire colours match to ones at the plug so im hopeful. Trying to get a plan or attack before i go start testing components.
The MAF on the car is only a 4 pin, leaving me short on the intake air temp sensor location.
Is there anywhere i can download a good wiring diagram, im finding lots of conflicting information on these cars.
The other issue i have is the o2 sensor plug (or what i assume is the o2 plug..) has only 3 wires but the sensor i have has 4 and the plugs are different. Can i splice this in or it a different type of sensor needed? would that be enough to stop the car firing up? If i can find the part number for the correct one i'll buy one to eliminate it as an issue.
Wiring diagrams for JDM Subarus are next to impossible to find.
The 4 pin airflow meter is also used on the 1999/2000 European Impreza Turbo for which workshop manuals are few and far between as they were only produced as paper copies.
The O2 sensor that fits in the LH manifold is P/N 22690AA440 and has a 4 pin plug with only 3 pins fitted
Having looked at some of the earlier classic Impreza turbo models( upto MY98) and they don't appear to have an IAT sensor, so i'm wondering whether your Legacy is the same.
Is the software you are using for diagnosis compatible with early Japanese Domestic Market (JDM) models?? as against Asian manufactured "for elsewhere" models, as most, if not all are non OBD compliant and only use Subaru Select Monitor (SSM).
Maybe that's why you get the strange reading as one is not fitted??
ECU's changed for the Impreza MY99/00 European models so probably the reason for the IAT being fitted remotely in the duct.
Having looked at some of the earlier classic Impreza turbo models( upto MY98) and they don't appear to have an IAT sensor, so i'm wondering whether your Legacy is the same.
Is the software you are using for diagnosis compatible with early Japanese Domestic Market (JDM) models?? as against Asian manufactured "for elsewhere" models, as most, if not all are non OBD compliant and only use Subaru Select Monitor (SSM).
Maybe that's why you get the strange reading as one is not fitted??
That could quite possibly be an issue. Ive used the delphi system, and a fully updated snapon verus. Sadly both show limited live data so i cant even be sure this is my problem. Im thinking if its seeing -40 it could cause an overfuelling issue. Im not entirely sure that would cause enough if a problem. Ive ordered an o2 sensor so can only try that when it arrives and go from there.
I'll be jumping back into work tomorrow to borrow the verus to scope the cam/crank, injectors and anything else i can find that might be an issue. Looks like im going to have to go back to basics and follow the process.
The biggest problem i have is i bought this car almost 5 years ago with most of a dismantled engine in the boot. I have no idea what issues it had the last time it ran except the bottom end rattle leading to the engine removal.
Bear with me hear some of this maybe incorrect but its not far away.
iirc the v3/4 jdm sti had an ats in the maf but also had a sensor in the intake scoop. Orange maf.
v5/6 sti had them in the maf too but iirc it was yes for sti and no for wrx. Depends how many wires into maf. Seem to remember jdm yes eu no.
v1/2 can't remember think it was sti/wrx dependant.
Now the sensor in the intake scoop iirc correctly on the eu models had something to do with outside air temp cause I seem to remember unplugging one and it wasn't working.
I think the legacy one is a purple maf which I should have floating about somewhere and the wiring loom and that due to the number of wires would tell us if it had an ats in it.
But the variations are endless over the years and are different between jdm and eu.
When fitting an aftermarket ecu 99% of the time you tap into the maf wires for ats.
Hope that helps/confuses you a bit
These cars seem to be a bit of a minefield when trying to find information. I was always more of an old Ford guy where you could find justabout any information you needed no matter how weird or wonderful!
Ive had a thought.. The inlet, injectors and attached loom im using is from a 2001 B4 RSK, im wondering if ive missed something when comparing the inlets and thats why im getting a fault here.
I'll go have a wee look at the scoop to see if theres anything there but i can remember seeing a sensor there. Thanks for the help guys.
Started from the start, disconected the harness plugs and cleaned them out then reconnected..
Sure enough she fired up! Lesson to be learned here i think.
Next issue..
I was getting oil at the pressure sensor when priming but the pressure sensor light never went out (sensor was an old one so ordered a new one) after she ran for maybe 4 seconds so killed it and tried to investigate. Replaced the sensor when it came, no difference then when i managed to get a hand i noticed air bubbles coming up to where the sensor is and confirmed the no pressure by cracking the turbo banjos When turning over with plugs out there is oil coming out the pressure hole but no great pressure. I put this down to it being a slowish turning engine but it looks now to be an issue.
At a guess its drawing/pumping air from somewhere, but where?
Can see me having to pull this back out and go back over everything.
Large 10mm allen key to the right of the crank pulley. Can't see why you have no pressure at all even if things were serious. Have a think over your rebuild and try and remember did you put it all together correctly with no spares.
Will have a look in the morning mate, thanks for your help.
This engine has been getting pieced together over the last couple of years so i can only hope my engine building is better than my memory. Sadly neither seem great atm
08 April 2020, 01:12 PM
IAT sensor on BH5 rev C GTB Legacy
