Attn: Outback BH (99-03, EJ25 SOHC) Drivers + Libs/Imps

Phizinza

Phizinza

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Attn: BH (all 99-03 Subarus) Drivers Outbacks/Libs/Imps

I need your help.

If you drive a BH Outback I need you to tell me if you sense any of these symptoms described here https://offroadingsubarus.com/forum/index.php?topic=1209.0

Please let me know, and also let me know if it is an auto or a manual you have.

I have driven only two BH Outbacks, and this has been an issue for both.

Also this applies to other EJ25 SOHC models such as the Liberty's and Impreza's.
 
Last edited:
Gidday Phiz

My 2006 N/A 2.5L Fox doesn't do anything like that ...

The electronic throttle does have a slight flat spot just out of idle, but that seems to be decreasing as I get more used to both the car, and the electronic throttle. Felt a bit weird for the first 5,000 kms or so.

I reckon that is also part of the explanation for my initial high fuel consumption around town - giving it more 'floor' than necessary. Initially, I was getting around 12.4 L/100 Kms. The latest tank (all on shopping pram duties) I got 10.7.

If I had the real time fuel meter that SWMBO's SH has, I reckon it would teach me to drive more economically in very short order!
 
There's been a few posts on this issue but I cant find them, they're either on ORS or AuSubaru.

I cant remember if a solution was found, hope you can...
 
Thanks for the link.

I know exactly what is causing it. It is not the clutch, as I replaced mine along with the flywheel for an aftermarket one.

If you watch the ECU (with OBD plug and FreeSSM) as soon as the idle switch turns to off (which is just as soon as the TPS reads a change) the IAC opens about 3 quarters feeding the engine more air/fuel and revving it. This means you never have just a little bit of throttle, its off or 1700RPM on.... It is all logic, nothing wrong with sensors or valves. The idle switch is a logic switch (not physical) and turns off when the TPS changes up.

I was hoping it was an isolated ECU problem to particular models, but it looks like it affects most, if not all, the EJ25 SOHC pre 32bit ECU's...


And the big problem is, the only cars that came with the 3 plug ECU compatible with these Outbacks are from cars with the same engine and era (which all have the same problem from what I can find out).

It really is driving me nuts. Almost at the point of getting rid of this car and getting another Merc (as well as getting an older subie again for a 4x4 toy).
 
Sorry I can't help out with any type of solution mate.
Hope you can find an answer & get it all sorted :)

Regards
Mr Turbo
 
None of the described problems with my '01 AT Outback.

Hope you can find an answer, sorry to hear of the troubles.
 
I would be very interested to see logs of the ecu from romraider or see what the IAC does in freeSSM with the auto outbacks...
 
hey Phiz.

I know it's a potentially expensive solution, but would an aftermarket ECU solve it?
 
I don't have the first problem (sensitive throttle, jumping to 1700rpm) but have certainly on occasion felt the cyclical surging on light throttle, usually when going downhill as you describe. I think the effect (and discomfort) is exacerbated by the amount of backlash inherent in the drive line as it clunks between acceleration and overrun.

I don't recall having felt it for a while - maybe I've sub-consiously learned to drive around it or have just got used to it. I'll try to replicate it again and report back.
 
Phiz, is there any possibility that re-programming the ECU (or whatever) could be the answer?
 
Yes it probably would. Finding one with available tunes for a NA EJ25. Maybe I will just have to go all out and boost it with custom fuel maps and all....
 
Can't reprogram the 16bit ecu's. And the 32bit ecu's won't work with the older cable type throttle ej's.
 
Driven a BH 03 Outback for a few thousand km and never had this problem. Not once, I found it to be very smooth and didn't have that dead spot just off idle most EJ25's of that era have. I would plug the scan tool in and measure it but the only problem is now that Outback has an EJ20T WRX spec engine and driveline in it.
However when RSR get's around to finishing my engine next time he is back(hopefully) I will be running it with my current EJ20 manifold, sensors and ECU(2 pin, OBD I) with a possible tune or aftermarket computer if needed.
 
taza said:
Driven a BH 03 Outback for a few thousand km and never had this problem. Not once, I found it to be very smooth and didn't have that dead spot just off idle most EJ25's of that era have. I would plug the scan tool in and measure it but the only problem is now that Outback has an EJ20T WRX spec engine and driveline in it.
However when RSR get's around to finishing my engine next time he is back(hopefully) I will be running it with my current EJ20 manifold, sensors and ECU(2 pin, OBD I) with a possible tune or aftermarket computer if needed.
Click to expand...

Few thousand is a bit of a large stretch :iconwink:

It did have the surging on idle/light throttle which was particularly annoying in stop-go traffic. The throttle was sensitive, but it didn't jump up to 1700 as yours does, usually it would go to about 1400 at lightest touch of the throttle.
 
I don't have the reported problem. I go along with what SIMSX says a few posts previously.
OB manufactured Nov 02, manual.
 
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