RomRaider

Hi everyone,

Ive got a 2001 bugeye wrx throwing a P0340 code in its memory, however engine light is not on, clear the code and it comes straight back when driving.

Every now and again the engine light will flash on for a second then off again after heavy acceleration right as you lift off the gas.

I have replaced all 3 cam sensors, tumble valves removed and codes disabled, new plugs, swapped coils with known good ones, checked cam and crank waveforms with a scope for any issues and all are ok, im starting to think its an ecu fault, but it only started after removing the intake manifold. I have also checked all connections and grounds at ecu and engine.

Has anyone here ever come accross this before? Cal id is A4sd501a, i did see a post on the scoobies uk page about possibly updating calibration but am unsure what calibration to update it to

you could try software upgrading it to one of the slightly newer roms but I've not seen this happen where an ECU decides there is a fault like this without some kind of external cause.

If you had the manifold off and managed to crimp a load of wires together on the harness when refitting it then you could have a problem there and that's what's throwing it off - or maybe the tensioner is giving up and some slack in the belt is happening when you lift off?

Have you logged the car to see what the VVT positions are like left and right are they matching up ok?

I believe ive solved the issue, several road tests and it has not repeated.

I spaced the cam sensor back with a washer and no more fault code.

I had scoped the output and it was not losing signal on the scope, but it is an inductive sensor so perhaps being to close was giving to high of a voltage reading, i could not find a waveform to compare at 3-4k rpm where the fault occured

that's quite strange, is it a non standard sensor or cam wheel or has someone been sanding at the engine where it mounts?

Sensor is a genuine unit, everything else i am unsure off, vehicle has had a new short block fitted not long ago by someone else though so who knows, i thought maybe the cam has some end float?

Have you checked that the coil connectors are OK? My car was throwing cam sensor codes and so I replaced the sensors, checked avcs solenoids, purchased a tactrix so I could view the avcs position, tried a heap of other things, only to eventually realise it was these coil connectors. The housings crack and allow the pins to vibrate and go loose - disconnecting the primary intermittently and sending back emf up through the wiring and causes everything to go haywire. It would only happen under load presumable when the coils were trying to pull higher current.

Coil pigtails had been replaced, i did repair the shoddy solder job on them but the fault was still present after that.

Litterally drove it with the fault occuring, ripped battery out, spaced sensor and refitted battery and road tested again multiple times without issue.