Ludford

I've been having issues with the car late and so many people are saying so many different things to me I'm starting to suffer from too much information

So I better start from the top this might be a long story.

I bought a 1995 Import WRX Model GC8C48D Engine EJ20GDW4HE a few weeks ago and a few days later it started throwing up 2 check engine codes. O2 sensor and Idle speed. And developed hesitant acceleration

Took it to a garage where it was discovered that the car didn't even have an O2 sensor, so I booked it in for a decat downpipe and o2 sensor install. This didn't stop either code showing up or the hesitant acceleration so the ECU was checked and it turned out it was running a chipped Z4 ECU which I was told was incorrect for the car. It was changed for a U8 ECU and the check engine codes and hesitant acceleration stopped.

Fast forward 1 week and the check engine light is on again and the hesitant acceleration is back. And now I'm being told that the U8 is the wrong ECU by another person and I need to go back to my chipped Z4 or risk engine damage with my mods (440cc injectors, Turbo back Exhaust, Pod filter). And not to worry about the check engine codes as it's cause I'm running catless and have a BOV.

So what do I do? Who's giving the right information.

Ludford

Second question. Can a chipped Z4 ECU be mapped?

jayallen

iTrader: (31)

You should be using 380cc injectors not 440's....Even with a chip in the board because i dont know any chips for pre 96 ecu's that are mapped for 440's

Ludford

I was told that the Z4 ECU isn't for stock injectors, arn't 380 stock? I've been told my injectors are 440 because they are grey and slanted.

You can see what I mean by conflicting info now

jayallen

iTrader: (31)

If they are grey then they are 380's, the Z4 is for stock 380cc injectors

marcevs72

iTrader: (5)

a z4 is for standard 380 injectors and tdo5 turbo,i have this fitted to my 93 wrx.get hold of a standard z4 ecu and swap out the chipped one.
the z4 ecu had a better map on as was from a later classic but is good upgrade for early cars and ups power to 260.

jayallen

iTrader: (31)

No need for anothet Z4 ecu just remove the chip and re connect the J1 resistor

Ludford

Also there's a bit of confusion over the way my ECU has been chipped, someone says it was a bad job.

In this image I've circles where a mircochip has been placed and the orange diode has been cut.



Says it should have been done like this image

jayallen

iTrader: (31)

The j1 resistor needs to be cut for the chip to work......

Ludford

Well I will try going back to my Z4 ECU and see what happens. I'm being told I don't need to worry about the check engine codes, they are a side effect from no cat and a BOV.

Hesitant acceleration is probably coil packs and nothing to do with the ECU.

jayallen

iTrader: (31)

Which resistor has been cut in your ecu? The resistor you circled is not the J1 which is the one that has to be cut for the chip to work.

A bov and no cat will not throw a CEL light.....Why dont you try reading the codes?

Also, usually coil packs cause problems under high boost unless they are totally fooked.

Ludford

Codes are O2 sensor and Idle speed.

There's nothing wrong with either of them so something's causing a false positive.

Don Clark

From the same Subaru-Impreza.org thread..............



and J1 resistor cut............. (not the same as yours)

dj219957

as above z4 ecu is for 380s. check the colour of yours. grey are 380s. if they are not 380s you are gonna need a remap hence poor running. if you dont wana run the chip no need to remove it just re connect the j1 resistor, or replace it with a switch on some wire to flick between maps.

Ludford

Can it be mapped if it has a chip on it?

dj219957

and z4 ecu, or u8 is fine for your car so long as it has 380s, z4 is the better ecu though.

jayallen

iTrader: (31)

Yes and no....No if its the stock ECU or the Stock ECU with a generic chip fitted but yes if it has an ESL live mappable board fitted.

dj219957

depends on the chip.

dj219957

best to confirm your injectors first.

Ludford

It's just a generic chip.

Worth getting an ESL and having it mapped? Is that expensive?

jayallen

iTrader: (31)

ESL i think is £500ish supplied fitted an mapped.

TBH, for the mods you have the stock ECU should work ok....with bov and decat.

dj219957

if i were you id ditch the bov and injectors and go from there. bov can cause all kinds of running probs and offer no performance improvment.

Ludford

Here's my engine bay, if someone can just point out where the injectors are on an Impreza I'll go check them out.

jayallen

iTrader: (31)

Right and left hand side of the inlet manifold.....If 380's they will be grey if 440's they will be yellow..

Have you tried a replacement MAF?

dj219957

that looks like a standard re-circ valve to me. injectors are next to each of the "prongs" of the inlet mani, where it meets the block

Ludford

They are grey.

Tried a new maf but the codes didn't go away.

jayallen

iTrader: (31)

Is the CEL permanently lit? If so it must be in Limp mode.

Ludford

Yes it is. But it's not in limp mode. I've been driving it hard daily.

dj219957

i would not drive it hard with cel on. it is there to tell you of a problem. if the car is running right and modded properly then it should not be on.

Ludford

Well I've been told that the light is just from the decat and bov so I shouldn't worry about it.