410 replies to this topic

[LukeFranky]

The cam shaft sensor looks simple enough. Only two wires. Can I test it with a multimeter? Anyone know what voltages I'm looking for at both ends?

[Robert]

Should have the exact reading in the fsm,
Can't remember exactly

Having a oscilloscope will be handy also cause you can check the waveform and shit like that

[duncanm]

I think the cam sensor may be a furphy - if it fires up and runs, the sensor is prob ok.  Its not going to give you shitty fuel consumption or P0171 codes.

 

I suggest you start from the beginning and use the factory diagnosis path for P0171 (System too lean)

1. exhaust leaks
2. intake leaks
3. fuel pressure
4. fuel injectors
5. coolant temp sensor
6. MAP sensor
7. IAT sensor

 

you will note that none of these suggest cam sensor to be an issue.

 

for injectors -- maybe just pull the plugs and check they all look the same. This will give you a quick indication if one or more cylinders is running lean or rich.

[LukeFranky]

Originally, before this whole saga began the cam sensor was causing a misfire at idle. It got worse with the lights on. The problem disappeared the moment I added an extra earth.

If that has a bad earth, maybe other electronic goodies do too...

 

Anyway... 

1. exhaust leaks - Checked.
2. intake leaks - Checked, but still a few suspect points to check.
3. fuel pressure - Haven't checked this, but wouldn't low fuel pressure present problems under full acceleration?
4. fuel injectors - Replaced. Might pull the plugs out anyway.
5. coolant temp sensor - Is it possible to test?
6. MAP sensor - Is it possible to test?
7. IAT sensor - Is it possible to test?

Wasn't MAF somewhere on that list?

[LukeFranky]

Is this the one Kong?

http://www.ebay.com....MUAAOSw37tWA2z2

[Reevesy]

Dodgy coolant temp sensors have been know to throw every other code under the sun rather than the coolant temp code. So it may be a good place to start for fueling issues.

[LukeFranky]

Oh BTW. The car no longer actually looks to be running rich. It's not leaving black soot on the bumper or blowing smoke. Overall it is running a lot better than when I started trying to fix this.

 

I also like to point out that when the car was physically feeling the symptoms of this problem, unplugging the MAF made it run pretty nicely.

[duncanm]

to check the cam sensor wiring - just use a multimeter between the sensor plug and the ECU plug.

 

Its two wires with a GND shield. Unplug both ends, check the 2 wires are low impedance (< 5ohm or so), check they're not shorted to each other or GND, give both sets of plugs a good spray with contact cleaner.

 

BTW - where did you add the earth?  Is this to the engine block from the chassis?

 

EDIT - check the earth on the camshaft sensor wire has a good contact to the chassis -- Pretty much all the chassis earths to the wiring loom - clean em all up and make sure they contact through paint.

[duncanm]

for the coolant temp sensor - get your OBD cable and freessm or something and just query the temperature seen by the ECU.  Check it matches actual temp over cold to warm engine.

[Samwise]

And yes I'm going to keep beating this dead horse.
cut your losses and either flog off the car, or Convert it to single turbo and enjoy hassle free boosting.

 

Why don't you shut up and convert your face to single.

[Samwise]

 

Say's the cheeky ranga who had a single converted TT.  

 

GT is that way Sammy >>>>>>

 

Hey! Hey! That was all on Will. I just bought the car lol.

[LukeFranky]

duncanm: I added the earth to a bolt that holds the heat shield onto intake manifold right near the cam shaft sensor. It attaches directly to the battery clamp.

 

 

The following might be of interest to you guys. Just took the car for a drive over my lunch break paying very careful attention.

 

First thing I noticed as soon as I started the car was the revs alternating up and down during the usual warm up cycle that Subarus do. The revs then settled to just above 1100 rpm before I drove off. After driving the car and warming it up the revs would settle down to about 800 rpm on idle with a slight misfire here and there. This is the first time I noticed the car revving up and down on startup. It didn't do it this morning.

 

Next thing I noticed was very dull high pitch whistle under primary boost starting at about 5psi. It's so quiet that I couldn't hear it under the boost of the secondary. It sounds a lot like an alternator whine coming through the speakers but it was coming from under the hood. First inclination was boost leak but I'm also worried it could be a failing turbo. My last turbo made a similar but much louder noise right before it blew in spectacular fashion.

 

Finally the only other symptom was surging boost. This is relatively new too. Today I was sitting on 5psi up a hill on the highway and then it would drop to 2psi and return back to 5psi in a rhythmic fashion. Could this be a sign of a failing turbo?

 

I constantly scanned the car. It never actually threw up an engine light but a pending P0171 code continued to taunt me.

[Robbks]

Keep it simple first

if you're hearing high pitched noises 99% it's a boost leak,
intake pipe, BOV gasket, bov itself, those silly spacers, turbo to TMIC pipes (cracked or loose.)

Dirty IACV and Housing is another distinct possibility and if you've got hunting rev's at idle then this is stop #1
Dirty/ Sticky throttle body.

Did the car have the spacers on it when you bought it?
if not, take them off, you're messing with airflow,

I also don;t know why a simple re-tune on an ECUtek'd ECU would be another $1500..? The ECU/ Car owner has already paid the licencing fee. It should just be the tuners time.