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ok this just gets weirder and weirder, throwing codes seems random


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Ok so I did a head gasket job on my 1998 Legacy Outback 2.5 auto... battery was off the car for about a week maybe a little longer

 

then got it all together and hopped right on the highway, drove 100 miles pretty much right away

 

about 100 miles later I get code that says idle control valve too high RPM or something like that...  this caused some odd idle issues, mostly flutter at idle after a stop, almost die, bounch up, 2 or 3 times then smooth out

 

I cleared that, then 150 or so miles later the car throws another code Mass air flow low input, caused a really erratic idle, going as high as 1800 and then falling to near 0 or dying altogeter

 

cleared that and a 100 or so miles later I got the EVAP emissions code

 

 

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The ECU needs to meet the logic requirements for the specific code so getting codes at different mileage, engine cycles, drive times is not that strange.

Clean the IAC

Clean the MAF

Make sure your gas cap is on tight and all vacuum lines are hooked up correctly.

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+1 on the requirements. I had a similar problem with a buddy's Impy.

 

It needs to run a baseline to figure out if the sensors are even working as well, how the engine is going to "run". 100 or 150 miles allows it to figure a decent average. 

 

In my case though, it was throwing the wastegate open and purging boost, kicking a MAF code as well as an O2. Turned out he was running 85 Octane when the book asked for >91. Obviously yours is probably not this case but sometimes its something simple like cleaning a sensor (or plugging one in, i've had those moments). 

 

 

good luck!

 

 

-Justin

Edited by crazyman03
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well I could only find the 'green' plugs, not the black plugs...

 

but the transmission was shifting a lot smoother after just following the instructions with only the green plug

 

then I took it on the highway...  ran it for maybe 5 miles with no issues, only down shifted on inclines or when you really hammered the throttle...

 

however there was one instance where there was some jerking at about 10 miles, I have yet to see this again, and still no CEL

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Wait and see.. maybe try unhooking the battery again and let it sit for a bit. Go back and Re-Re-Recheck your connections. I know you probably already have but just do it again and make sure they are tight. Sometimes it takes going back and retracing your steps. 

 

 

-Justin

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No change. About 15mpg for last ten gallons. Lets look at what we know.

 

1. For the first 6000 miles I owned this car the only thing I noticed was that it was throwing a code for an evap. And it would misfire sometimes if it was not warmed up. Then it would do a flshing CEL. then run just fine.

 

2. A few weeks ago,

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2. A few weeks ago it blew a head gasket on the highway and was driven home overheating and stopping often.

 

3. When I got home I disconnected the battery and started working

 

4. The 3 main harness plugs where disconnected.

 

5. The plug on the front o2 sensor got the wires pulled out of the plug... however I was able to get them back in the plug... 2 whites 1 black wires

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Several frames show your long term fuel trim is maxed out. The ECU is dumping fuel in for some reason.

 

The O2 sensor voltages are a little on the lean side in the later frames. Are you sure you don't have any vacuum leaks?

No exhaust leaks at the manifold?

Edited by Fairtax4me
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Several frames show your long term fuel trim is maxed out. The ECU is dumping fuel in for some reason.

 

The O2 sensor voltages are a little on the lean side in the later frames. Are you sure you don't have any vacuum leaks?

No exhaust leaks at the manifold?

actually there is an exhaust leak now that you mention it...  reused the gaskets, just have not had time or money to fix it

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Yeah. Your fuel trims are whacked. It's easy to knock a intake gasket out of place and cause issues. I would also make sure you have the O2 pins back in the correct locations. That could easily be causing the fuel trim numbers to be off. The transmission isn't slipping. It's hunting. It looks like the transmission is downshifting and upshifting at will. My first thought was the Throttle position sensor.

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could some one explain to me how to read the fuel trims?  the intake gasket is new and good, however I know at least the drivers side exhaust mani is leaking at the head(reused the head to exhaust mani gasket)  could this be causing the  o2 to THINK its lean, hen dumping fuel to 'fix' the problem

 

I think I figured it out Long Term fuel trims maxes out at +27.3...  several frames are a that rate

 

Yeah. Your fuel trims are whacked. It's easy to knock a intake gasket out of place and cause issues. I would also make sure you have the O2 pins back in the correct locations. That could easily be causing the fuel trim numbers to be off. The transmission isn't slipping. It's hunting. It looks like the transmission is downshifting and upshifting at will. My first thought was the Throttle position sensor.

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fuels trims should be low. folks start getting concerned at double digits. maxed out is very bad.

 

double check cam timing. cars will run (poorly) 1-2 maybe 3 teeth off time.

 

On some older cars, there's a commonly corroded/loose harness/connector in the back on top or near the charcoal canister. On newer cars, the valve is under the hood.

 

might be a good idea to try a vacuum gauge.

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ok the exhaust manifold gaskets did not help...

 

I took a closer look at my vac hoses, then I traced the line running to the FPR, it ran under the intake on the right hand side...  to a metal line, that ran to NOTHING...

 

well I added a T and hooked the FPR back up, reset the car and fired it up...  instantly had a better idle

 

ran 2 test runs and got similar results...

 

 

http://txtup.co/iVJPd

ALSO there is a device under the intake on the right hand, rear side that has a vac hose and some wires running to it, but its not hooked up to a vac hose, and IO don't recall unhooking it, nor is there a port to hook it up to

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