Classic misfire.
 

Just replaced my engine on a V2 STi Wagon with a motor from a V2 STi saloon. I have a slight misfire under load.

Now the old motor was 260ps the replacement is 280ps. Was that extra 20ps gained from ECU mods? I mean there is nothing different with the two engines is there?

New plugs, gapped at 0.7mm and new coils in so am a bit stuck, no air leaks at all, all new gaskets replaced when i did the engine. Timing is perfect too.:freak3:

The ECU's are different ? My wagon has a specific STi wagon Chip GF8, I assume the saloon has a specific chip GC8. I don't know why this would cause a misfire though as the guts are the same ! Boost cut is 1.2 IIRC what does it read ?

STi v.2 wagon = 260PS
STi v.2 saloon = 275PS

I believe the extra power (and a bit more torque) is obtained, as you say, by the saloon's ECU running a bit more boost/fuelling/timing. I think they are the same engines, hardware wise.

Are you running the saloon's engine on the wagon's ECU, though?! Its lower boost/fuelling/timing could be the reason for your misfire - but no reason why it should be!

If you are running the Wagon's ECU, then the saloon's motor wil theoretically be making only c.260PS too.

Interesting. According to Roojai...

Roojai Subaru Impreza

... Saloon has a TD05 16g running 380s
BUT Wagon has a VF23 running 440s!

So, if you wholesale swapped over to the saloon's engine - INC. its different turbo and smaller injectors! - BUT still using the wagon's ECU, then the fuelling/timing no doubt won't be appropriate.

Whether it could promote an ignition misfire though; not sure(?)

FWIW my wagon and most others I have fondled :D have had TD05 and 380's, I think it depends on what was on the shelf at the time of assembly tbh.:lol1::D

I've only ever seen V2 STi wagons with a TD05 and 380cc injectors, I wouldn't put any stock into that link.

Yeah I agree!

I'm sure it still does have a TD05 top entry and 380's - it's the "phase 1" STi engine still, after all.

I agree as above - sti wagon or sti saloon pre'97 should have a TD05 & 380s. Your Ecu should have 6K written on it to match the engine for 280ps.

Check under the passenger footwell for the code (doubt this would cause a problem though unless you had an non-sti wagon ecu in it at the moment as they run TD04s I believe)

But if it's a wagon STi ECU you won't have the map for 280. Doesn't answer the misfire question, but good to know all the same.:)

This is my ECU removed in favour of Simtek. Top left you see it is GF8STi.

http://i166.photobucket.com/albums/u105/BMGC/jecs1.jpg

53WRX is right.

As I posted above:-

-STi v.2 wagon, 260PS
-STi v.2 saloon, 275PS (not 280, lol) - so different map to the wagon's.

Only the MY97-00 (v.3-6) saloons had 280PS (both STi and WRX)

As said, doesn't necessarily answer the misfire question though.

Sorry, my bad. Should have said 275ps (not 280ps).

Fatsboyslim - I would still check what ecu code is currently sat in there as they do tend to get swapped about over the years for whatever reason, unless you know it is the original one but not mentioned it.

It is a standard Z4 ECU. I just used the replacement long block, all the rest is my standard stuff. Maybe i should do a ECU reset?