EJ25 confusing power issues

foxx510 · Post by **foxx510** » Wed Jan 30, 2008 1:27 pm

If you leave the battery disconnected for a while it resets the ecu, yes. Short disconnections don't reset it.

SUBYDAZZ · Post by **SUBYDAZZ** » Wed Jan 30, 2008 1:47 pm

How long is a while? I assume it doesn't use a flash memory then.

foxx510 · Post by **foxx510** » Wed Jan 30, 2008 2:22 pm

I'm not sure exactly, but I had to leave mine for more than a few minutes.

FROG · Post by **FROG** » Wed Jan 30, 2008 3:00 pm

i always thought an hour then take it out for a hard run up through the rev range

madmat · Post by **madmat** » Wed Jan 30, 2008 7:17 pm

i was doing about 10 minutes with the ignition on so that it was pulling any power left in the system. it worked

foxx510 · Post by **foxx510** » Wed Jan 30, 2008 7:36 pm

Sorry if this is obvious, but you did do the same ~10mins cooldown without resetting the ecu and the problem remained until you did a cooldown and reset?

madmat · Post by **madmat** » Wed Jan 30, 2008 8:28 pm

yes it is always there and the only time it goes is after the ECU reset.

i have just put all the original sensors etc back and it made no difference. it is just gutless no power at all. seems to idle ok and revs all the way but not as crisp as i would expect.

this is what i have swaped the igniter, AFM, Knock sensor, Crank angle and Cam Angle sensors and they make no difference at all it is just the same. i can bearly drive it

when i pull the injector plugs the cylinders drop even amounts which says to me they are working the same amount.

i'm going to take it to a mate with a code reader and see if he can get more out of it than i do. fingers crossed.

madmat · Post by **madmat** » Thu Jan 31, 2008 10:46 am

I am going to persu a new avenue af thought now;)

lying in bed last night i was thinking maybe the the cam gear is different on the new heads and so sending poor info to the sensor:rolleyes: i will swap it over today and see. fingers crossed.

FROG · Post by **FROG** » Thu Jan 31, 2008 10:50 am

what you get the new heads out of?

98choppa · Post by **98choppa** » Mon Feb 04, 2008 6:52 pm

i think...
please change your 02 sensor,if you can try anothr one in there do it.my gen2 rx ran just as you described!i was very shocked at the massive effect of the sensor on the car....going up hills started to hurt,car nearly bunny'hopped at times,went hard for a second then back again?!

ive actually seen on another car the harmonic-pulley bolt come loose after a major service(wiggling-in-your-hand loose)and the timing was found to be physically off its dial'

madmat · Post by **madmat** » Mon Feb 04, 2008 7:37 pm

Thanks 98choppa i have tried that. i have swapped out every sensor and pickup in the engine managment system. i even changed the wiring harness for the engine sensors etc. i have swapped the ecu as well. i've cleaned all the earth conections as well. iv'e used different plugs, leads and coil. nothing makes a difference other than if i reset the ECU it will run perfect until it gets up to full temp. then i can watch as the revs drop during a stall test from 2200 to 1700rpm in about 2 seconds. it is totally repeatable.

iv'e got so desperate i'm going to swap out the transmission that i put in while i had the engine out to do the heads. my faint hope is that the auto is sending the ecu some sort of i'm not happy signal that makes the ecu pull back the power of the engine as a way of preveting further damage to the auto.

:???::???:

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Mon Feb 04, 2008 11:53 pm

Just another thing to check, your knock sensor isnt loose is it? If it is the ECU will be detecting knock all the time and flooding the engine with fuel and retarding the daylights out of the ignition timing.

madmat · Post by **madmat** » Tue Feb 05, 2008 7:51 am

i have changed the knock sensor and it made no difference.

madmat · Post by **madmat** » Sat Feb 09, 2008 8:47 pm

An update on this in week 5 now. as a last ditch effort i swapped the trans back over hoping it was causing the problem and you guessed it it was not the problem. i was talking with a neighbor today and he has suggested i check the voltages at all the sensors going into the ECU to see what values are going in.

we have a love hate relationship with the Subaru at the moment. i hate to love it and it hates to love me.

foxx510 · Post by **foxx510** » Sun Feb 10, 2008 1:12 pm

Changed the ecu yet?

madmat · Post by **madmat** » Sun Feb 10, 2008 8:16 pm

yes did that

Morcs · Post by **Morcs** » Sun Feb 10, 2008 10:00 pm

I think you may have a cam timing issue, My Brumby with ej20 had a problem that couldnt be found by a few mechanics before i bought it. Had it at my place found that the woodruf key on the crankshaft had shorn off and let the cam timming wonder. It would start and run for a few seconds then die no codes etc. Would explain backfires and not running above certain revs etc and no codes. Mine had freeplay on the belts i could rock them back an forward 1/8 turn before it would start to turn motor over. Check it out as this is quiet a common problem.The bolt had bottomed out and pulley was able to move around eventually shearing key. There is a fair amount of load on this key from 4 cams etc.

madmat · Post by **madmat** » Mon Feb 11, 2008 7:20 am

Thanks Morcs i have checked this out 4 times already and it is all in Good condition.

Morcs · Post by **Morcs** » Mon Feb 11, 2008 8:15 pm

Vavle Clearences maybe too tight causing vavle to ride open when every thing heats up (expands).
Can you get access to a data logger?
I would have ago at logging afm and O2 senser.
Afm Sensers can be finiky things at the best of time,
log to see if they go out off range.
All else fails could be making a trip down sydney l8tr this could try swaping it for my link ecu.
As link Ecu does not use AFM input.

foxx510 · Post by **foxx510** » Mon Feb 11, 2008 8:18 pm

Stick a vac meter on the inlet manifold and see what's going on, the Haynes manual I have here explains what faults all the different readings mean.