Hi guys

any one got any ideas about this one ? i have a 1996 wrx that will start and run perfectly from cold for about 6 to 8 minutes then it will missfire and stall
it will then restart relutantly and only run cleanly above 2500 rpm !!
if i push the cam sensor towards the ferite pick ups un the plastic cam wheel it runs ok at all rpm for a while then it gets worse again, the only way it will run ok all the time is if the sensor is actualy touching the cam wheel
i have changed the sensor for new one tried another ecu and cheked the wiring for high resistance which is all ok

so what do ya think any sugestions ???

 

Any fault codes stored in the ECU ??

 

no forgot to say it is on a gems ecu so no fault codes but i can view live data and see what is hapening with the cam signal

 

The running issue sounds like it could be the coolant temp sensor. When these fail, car will start, run for a bit, then stall

Just a guess...

 

If your convinced its the Cam sensor causing the problem and have replaced the Sensor, then check the resistance of the wiring harness from the Cam sensor to the ECU (with sensor and ecu disconnected) to see if you have any breaks/corroded terminal pins etc.

 

Sounds like a wiring issue, also worth inspecting the condition of the cam pulley and pick up points if possible.

 

allready done all that and all ok realy got me stumpt this one coolant temp sensor values are good but changed it any way and still no better ??????????

 

sumbody else must have come across this one surely ???

 

Back to basics then,
Has this happened since fitting the Gem's ecu?
Have you done any mods Prior to the problem occuring?
Compression Test - any sign of a head gasket failing?
Spark plug gaps and condition - coil pack breaking down?
Is the Fuel pressure/fuel supply ok when the problem occurs.

Just a few thoughts tbh

 

yep all these ok the car has run ok for 6 months on the gems ecu but i have tred a motec ecu and the problem is the same

new plugs coils fuel pump nowt makes any diference to it only pushing the cam sensor forward to touch the pulley it gets gradualy beter untill it actualy touches then its fine !!! how bizare

 

i had the same issue on my old wrx. would start from cold but not again if it was slightly warm. turned out to be the cam sensor. just replacing the sensor cured it for me. so sounds like the wiring or maybe the pickup on the cam.

 

yeh but new sensor fitted and wiring all checked out ok and still just the same its doing my head in now
surely some of our resident experts must have some idea of what to try next
please help cheers

 

was it a bran new sensor

 

Is it a genuine Subaru sensor - OEM Camshaft sensor is shielded and the resistance of the sensor should be 950 ~ 1250 ohms.
The air gap between the sensor and trigger segments on the back of the LH Inlet Cam pulley is fixed by the position of the mounting lug on the cam cap - so might be worth checking the trigger segments for wear/dirt etc on the Bakerlite pulley and ensure that the cam pulley retaining bolt is tight.

Mick

 

thanks for that mick do you know what the senson air gap should be by any chance ? and yes it was a new genuine subaru sensor that was fitted

cheers

 

does any one know what the air gap on the sensor should be ??

 

Dont think any of the manuals will give an air gap setting as it is fixed and non-adjustable.
You need someone who has their heads off the car/doing an engine build etc to measure the gap for you as when the engine is in the car,the LH Inner Timing Cover shroud's the rear of the pulley where the trigger points are.

Mick

 

i have mesured the pick up gap and its the same as on my other car within
0,05 mm so i recon thats not the problem

any more ideas ???????????