Ive fitted a 2.5 sti engine into my wrx, having swapped the loom, sensors and removed the avcs. The engine runs, but doesn't idle. Do I just need a remap? (Ecu-Tek ECU)

 

So just to be clear, you have used the 2.5 heads that came with the engine?

 

Further to the above, have you used your WRX inlet manifold (+injectors etc.) or the STi one?

 

Oh dear, can of worms.

 

I'm doing the same with my 2002 WRX but with a small difference.

I'm fitting AVCS heads which will be run by the Syvecs ECU using the std 2002 WRX harness the AVCS will be activated by the redundant tumbler wiring as I have a Spec C manifold therefore tumbler delete.

You will definitely need a remap to get the engine to run safely plus if you have AVCS heads and do not connect the AVCS then you will lose a lot of top end as the cams will not open. My suggestion is to get onto one of the aftermarket ECU mappers e.g JGM, Pat Herborn, Zen etc.

 

Most would convert a WRX the same way, seems minge will have a few problems getting his going properly the way he has done it if he gets it going at all on the OE ECU

 

hmm......unfortunate

 

yeah, used the 2.5 heads and sti intake manifold.....

 

bump

 

p.s tomtit88's a w@nker

 

What model year is the original car? If it's a pre-2006, the reason it won't idle is, among other things, because the injectors in the STi 2.5 manifold flow something like 50% more fuel than the ECU currently expects.

The cam timing is likely to be all over the place too. Non-AVCS engines pick up their camshaft position via a single sensor reading reading pulse marks off the back of the left hand inlet pulley. Single AVCS cars have a pair of sensors (one per bank) keyed off the camshaft itself. Having never actually compared them or tried it I have no idea whether you'll be able to make this work satisfactorily on a non-AVCS ECU. If the reluctor marks on the AVCS cam are different (or in a different rotational alignment) to the ones on the back of the pulley, for example, the ECU won't be able to establish the timing properly.

Even if all the timing marks are cross compatible, you're running STi cams on an ECU expecting WRX ones.

Short answer is yes, it needs a remap, but even that may not get it running satisfactorily, due to the differences between the engines. As has been said, this is a bit of a can of worms, and the easier ways to do this job would have been to use either the matching STi ECU and loom, or an aftermarket one capable of controlling the valve timing properly.

 

Splitpin....... Just a quick question along the same lines

If I buy a 2.5 short block can I put my MY02 WRX heads and ancilliaries on it (includes pink injectors and TD05 18G) and map the thing ?

Shaun

 

the injectors are 550cc as were fitted on the engine that came oot.