joys of evap system, clogged lines and poor performance

[driftedoff]

My '96 Outback has almost 200k on it. It was having a bunch of performance issues and started to get so wonky it was lurching around and became almost undrivable and began wasting gas after swapping transmissions for a working one. Probably mostly unrelated

 

I replaced the O2 again after putting in new cats, unclogged the egr transducer, and replaced the fuel injectors. I had done a few other things previously like replace the wires and regap the plugs,

dismantle and check the intake with its gaskets, tightened the vacuum lines, checked timing and replaced the belt getting it to spec. unclogged the EGR itself, although I'm not postive that its working perfectly.

 

Now I'm not getting anymore CELs and the car drives reasonably. Still got a few issues with MPG and HP rough idle, poor throttle response and things like that

 

I'm going through everything I can under the hood and noticed that at least one line leading from the Evaporative Canister to the intake is clogged, can't blow through it. Question: How do I unclog the metal tube portion of that run? Or am I on the wrong track with this?

 

[driftedoff]

Did get a code finally- p0130 oxygen sensor error. i think the problem is that there is the wrong amount of oxygen in the exhaust rather than a faulty sensor. WIll pull and inspect plugs to see if Im running rich or lean in the chamber and eventually get a live feed of O2 sensor data.  First, next step is to put pressure into those lines that return the fuel vapor from the gas tank back into the intake to try and blow out any crud. Getting the fittings together to do that is going to be a pain. After that I'm going to reinspect the IACV, EGR and test the purge solenoid even though they aren't throwing codes.

 

didn't mention that i had replaced the fuel pump, minor.

[Fairtax4me]

I haven't ever run across a clogged metal evap line but if a big enough chunk of carbon from the canister makes its way up there it would certainly clog it.

 

Compressed air might blow it out but if not I would just bypass it altogether and run a hard plastic line.

 

A clogged evap line will not cause the problems you're having though. It will eventually set a code for Evap purge flow insufficient, if the line is actually clogged, but will not cause any driveability issues.

Rough/ low idle and poor throttle response are often caused by a vacuum leak. If you've been messing around in the area of the purge solenoid, make sure the vacuum hose that runs to the Fuel presssure regulator didn't get knocked off.

 

P0130 indicates the ECU is not getting a signal from the front O2 sensor. If you just replaced that sensor you'll want to make sure its plugged in all the way (they can be difficult to get clicked all the way together). Then check the wiring for cuts or breaks. Make sure the wires on the sensor are not rubbing against the cv axle.

[driftedoff]

Ok. Thank you for the feedback. I'm abandoning the idea that it is the evap system that needs fixing which makes my title wrong. I'm going to operate under the assumption that the computer is not getting an O2 sensor signal.

 

The oxygen sensor's wires aren't frayed. I had maneuvered the leads so that they wouldn't touch the spinning axle. I have the sensor wire from the Bosch sensor I put into the front

Cat hooked to the Grey wire coming out of the same wire bundle as

the two heater wires. (The snap connector is long gone) I am not getting the heater

circuit code from my cheapo scanner which only gives DTCs and no specific data.

The grey wire is wrapped with another wire presumably to deal with interference

and is in the right location. It fits the description of the Line to ECU for O2 sensor data.

 

Things to check on:

1 )  Could it be that I have a bad ground? The vehicle has been experiencing some strange electrical phenomena which I have attempted to fix up by putting in bigger grounds wires . The one I hadn't done is from the Transmission to the Chassis where the transmission stopper connects to the body.  Specifically, turning the key doesn't always activate the starter and it seems to be worse when accesories are going such as the fan. The wire from the starter/engine to the negative terminal on the battery was upgraded.

 2)  I used a universal Bosch sensor maybe its not sending

a signal that the ECU is able to use and a stock one would be better although I read reports that the

Boschs univerals work.

3 )  Is there a break between the o2 wiring and the cpu? Those wires disapear into the passenger side firewall and I guess makes a right turn towards the driver side clusters under the dash. I could try to locate this wire close to the ECU and try to get some evidence of a signal with my digi multimeter.

 

[Rooster2]

My car was running poorly at times. I got some maybe bad gas, but changing the fuel filter under the hood helped a lot. Got lots more power, and better driveability.

[driftedoff]

bad gas from where?

i changed my filter and nothing interesting happened

[Fairtax4me]

Is it a 3 wire sensor or 4 wire sensor?

[driftedoff]

3 wires come from the O2 sensor.  

 

I have now upgraded the ground wire that goes from the firewall to the transmission.

I also found a questionable ground connection to the intake manifold. tightening bolt.

[driftedoff]

I also took off the IACV and it isn't airtight when its closed. I wonder if that's normal.

[Fairtax4me]

IACV is not air tight. It is supposed to move freely.

 

Transmission ground doesn't really matter but the grounds on the manifold are for the ECU. Those will cause some problems.

 

Pretty sure that car should have a 3 wire front O2 sensor so you should be good there. Only issue might be if its wired incorrectly. On a 3 wire sensor the odd colored wire is the signal wire. The two same colored wires will be for the heater element.

[driftedoff]

On the sensor i aquired there are 3 colors: white red black.  Black and red were put on the two legs of the heater circuit. White was connected to the black signal wire with the grey outer cover.  Strangely My Hanes, or is it Chilton.. manual says to put white wire blue stripe one way and the FSM says to put it another- front vs. rear sensor heaters for those wire colors. I tried both along with switching the black  and am still pulling code p0130 Bad grounding through the front cat bolts?

[Fairtax4me]

You have probably cooked the sensor element by feeding it 12v.

 

Bosch sensors typically come with a wire diagram to tell you which wire is which on the sensor. Connecting it wrong can kill the sensor and in some cases damage the ECU and sensor.

 

You need to verify which wire does what on the sensor and make sure its hooked up properly rather than guessing. I'd recommend a direct fit sensor at this point.

[driftedoff]

They should have sent me a wiring diagram. Didn't put either of the heater related wires onto the white wire which is signal on those sensors.

For the vehicle side, the Haynes manual contradicts the FSM for the white wire and the white/blue stripe on a '96

Speculating that the error wasn't caught since they can be wired both ways.

 

CEL has subsequently disapeared on its own. DTC Fell back to freeze frame data on my cheap scanner.

Rough running got a little better. Ready for inspection.

Edited August 23, 2014 by driftedoff