3barboost

Hi

Help again please !

The car is a MY98 STi4 2 door - previous owner may have "swapped" the ecu

With ecu code 75 it boost cuts at .6bar but revs to 8krpm (in the car) shows error code 44 permanently - with wastegate solenoid error

With ecu code 6S it doesnt boost it revs to 8k rpm and goes very WELL - no codes

With ecu code 3I it boost but limits to 6.5k rpm (spare from breakers) - no codes

The ecu code 6S was loaned from a MY97 4door sti ?

These are all the ecus with the correct plugs to plug into the sti4 harness that we have access to here in South Africa

I need to know what ecu the sti4 should have please, what options are there for mapping and any for sale ? (once I have the correct code I can go shopping !)

Thanks for the help - again !

H

Sprint Chief

Correct ECU for a v4 STi is the 75.

The 6S is the correct ecu for the v3 STi.

0.6bar will be the actuator only boost, caused by going into "limp home" mode following the fault code. Did you try a reset? (Although disconnecting and reconnecting will achieve this). Have you tried the test connectors and listened to the boost solenoid, make sure it is clicking?

3barboost

Hi Sprint

ok - with the 75 ecu the car immediately throws the wastegate solenoid error code - shown by counting the check engine light flashes - by connecting the test connectors - I will go listen to see if the solenoid clicks - we have tried as many wastegate solenoids as possible and hooked up the boost lines differently - ithe error is the same - f we plug in the other ecu it allows it to boost but rev limit is reduced and no error code is shown - so that shwos the solenoid is working - my thinking is that by this elmination that one of 3 ecus throws a wastegate code - maybe that ecu has a fault in its wastegate circuit ? anyone got a spare correct ecu for sti4 for sale ?

Sprint Chief

Agreed, if you've done all of those checks it sounds possible that the ECU has developed a fault. Just trying to think of anything else that might cause this problem? I'm surprised the 6S doesn't boost at all though.

I'm not familiar with the 3I though, ecus I'm familiar with for 97-98 are 1S/2S/3S/6S/8S/75/88/89/8Z/SP. I wonder if the 3I is for your local market? (The 8S is the UK/European local market ecu).

As a short term fix you could consider running a manual boost controller to control your boost. This would bypass the 75's boost control circuit. You will need to make sure you stay below the boost cut, and it would probably be wise to monitor the car for knock levels, just in case there is another problem hiding somewhere.

Apexi PFCs as a mappable aftermarket ecu are very cheap for this year of car, available from Nengun in Japan at very reasonable rates, although you have to wait for it to be shipped. You might have a local supplier who can help.

Specialist subaru breakers in the UK would probably charge around £100-150 for a 75 ecu, and I wouldn't expect to have too much trouble finding one in the UK, but I don't know what the situation is like where you are - lots of JDM scoobies around these parts

3barboost

hi - being in South Africa there are only 2 legitimate (and about 3 illegal) imports of sti 4 in the country - no sti 5 and 12 sti 6 and 1 22b
so breakers are out of the question !
I have helped fit apexi to other classics - but the idea is to keep the 2 door as close to orig as possible.

I have a post in the wanted section looking for an ecu as I think its wastegate circuit is stuffed - the actuators default is .5 and even with a pipe looped from compressor to actuator the boost cut still gets triggered as the boost creeps slightly up as the revs increase !

Thanks for the info and if you know of any that are up for grabs please let me know