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the ej20t has started choking down at about 4500rpm. I'm not sure what's causing it, but when it hits 4500 it starts to surge and won't go any higher, almost like there's a rev limiter or something at play.

no idea how these new fangled EJ engines work, so am at a loss where to start diagnosing.

found the error code wires. Errors 22, and 33. I google them as being Knock Sensor, and Speed Sensor.

Faulty knock sensor might cause it ?

Could be a faulty knock sensor, or it could need a speed sensor input if you haven't connected it. Years ago on a Nissan transplant I did I had the same problem from not having a speed sensor hooked up, hit a brick wall around 5000rpm or so.

Sounds like an airflow meter related problem, try swapping out for a known good one. Problems like this can occur without it actually throwing an airflow meter code. Is it an early RS EJ20? If so it's handy to know that a very common early liberty EJ22 airflow meter is exactly the same so quite easy and cheap to source replacements or borrow off people.

Target the knock sensor too tho....it seems heaps of EJ looms that have been cut down spit code 33, there is a way to stop this but I forgot what it is, I think you have to put a resistor somewhere in the loom. Mine spits code 33 all the time and doesn't have your described problem so it's probably not your problem.

Have you got a boost gauge?

A knock sensor fault will retard the timing and cut boost to the minimum level. This could be your brick wall.

if its throwing a knock sensor code it would make sense to look there first...

have a look at the thing. they go brittle and crack over time. you will be able to see it just looking at the thing. they are about $140 new from subaru.

Worked out how to clear the codes, as soon as I did that the car came good. Hopefully the code doesn't come back, I've been told that it could have been a bad batch of fuel that caused it to give bad readings.

I've had several bad batches of fuel in the last month or two. The old carb'd EA82 didn't like it at all - wouldn't idle, no power (in EA82 terms) and the poorest fuel economy I've ever seen with ordinary driving...

Stinky I hope this is all that your problem is. My fuel came from a large "reputable" service station company...

Bennie

El_Freddo wrote:
My fuel came from a large "reputable" service station company...

Bennie

has to be an oxymoron these days doesnt it

have you had a look at the cat to see if its not blocked . . . . .my2c

It won't be the VSS. I don't remember which computer is in that car now. I do know that when it has/had a series 1 Legacy computer in there it would not do VSS code. With a series 2 or WRX ECU it does do the code. There is a slight difference in the pin-outs on the computers with minor sensors. The main pin-outs that run the car are the same.

It may have been the knock sensor. I have had other cars do the same thing and have been trying to remember what it was that caused it. I have a feeling that in the first white Liberty I had I had issues with the knock sensor and it did do the same thing but only when it was unplugged. It would retard the timing and have no power with it plugged in. I just took it off, cleaned both surfaces and refitted it to fix it.

Maybe yours got wet or has a bad connection. Might be worth looking at. If it turns out to be the sensor is faulty you can fit any knock sensor from an EJ as long as it has the same plug.

thanks Brett. It's been running fine and hasn't thrown any errors since I cleared the codes. If it comes back regularly I'll start thinking about taking action.

my bet is on the knock sensor too.

once they are cracked they play up when they get moisture in them. Once you get some heat in it and dry it out, the fault will go away.

unless yours is 1/3 missing and filled with silicone like a certain Byron I know... then it plays up all the time!!

Just as a note on this subject. I get a knock sensor code when my engine bay gets wet and the car runs similar to your describing. If i clean the maint engine conectors with electrical cleaner this intantly fixes the problem.

Dave