MAF Code, New MAF, still there

I've had a problem with my Legacy since I bought it years ago.

 

When going up a steep grade in 3rd 4th or 5th, anything that sustains the revs above 3000 with a good bit of load, my car will start to stink like burning catalytic converter. Then, the cruise will start flashing. If the hill is long enough, the check engine light will come on.

 

I have to reset the check engine light a lot just to keep this code at bay so I can use my cruise control.

 

It throws P0103 - Mass Air Flow (MAF) Circuit High Input, sometimes the code for "Circuit Low Input" too.

 

I replaced the MAF with a brand new part, and this still happens. I also installed a brand new catalytic converter, neither of these parts made any difference.

 

No matter how well I seal the exhaust, even with copper high temp RTV, it always sounds like there is a small leak under my car, towards the firewall.

 

Is it possible the EGR is leaking exhaust somehow and causing a code to be thrown under load? For me to smell the stinky exhaust says something is leaking up front to me, but I don't know. The oxygen sensors are original, but I've never seen a code for them ever. I can't think of any other place it would be leaking from. Whenever I remove the manifold gaskets, there are no signs of exhaust leakage.

 

Any help is much appreciated, I can't even take this car on trips without my code scanner/eraser anymore.

I was going to say check the EGR and the EGR return line to the head.

It all looks clean, no air puffing out of them, no sooty residue around the pipes. I'm stumped.

New cats, new MAF and it still stinks on hills as if the cats are clogged ? When you put the new cat pipe in did the problem go away ?

Yup, still stinks. There was a small exhaust leak AFTER the cats that I just had patched up today. I didn't get too many hills to test the car on, but could an exhaust leak AFTER both O2 sensors have any effect on the engine management? The one hill it usually triggers the flashing cruise light on, I didn't smell any burning cat today, when I usually do every time.

 

If the exhaust leaks weren't causing it, really the only thing I can think of is O2 sensors.

 

When I put the new cat pipe in, it actually got worse I think, because of small exhaust leaks at the manifold to cat gasket. That 2-bolt flange really is absolutely horrible on the '05, it's worthless, it bends, it warps, and never seals right in the middle. I finally conquered it with a new-ish unbent manifold, but sheesh!

Circuit high or circuit low is an electrical problem. You either loosing the signal wire or it is shorting intermittently. Check the pins on th MAF connector, inspect wiring for chaffing, possibly run an new wire to the ECU.

Well that ain't good.

 

The problem is only replicated on long hill climbs though.... or if I'm WOT for a long period of time (0mph to highway speed++)

 

Pins at the connector have been cleaned with a Q-tip and isopropyl alcohol, they're dandy, so it must be elsewhere.

It kind of seems like my exhaust leak being repaired fixed the problem. This makes no sense to me, as the leak was post-cat.

 

What in the world.

Problem with error codes, they are not necessarily specific. An issue in another area that isn't necessarily monitored will throw things out of whack that *are* monitored, and it's those other things that will throw the code. The MAF error code seems to be used as a catch-all for anything in the system that's air/fuel related.

 

Regards,

 

Paul Hansen

http://www.avoturboworld.com

facebook.com/avoturboworld.com

That's what it seems like! I wish there was a way I could test a new O2 sensor to see if that fixes the problem. Only thing is, I'd need to return it if it didn't

 

The cruise started flashing again today, so the problem is definitely not fixed.

I just had a thought... Someone on the Volvo forums I frequent said that their weak fuel pump caused a lean condition, causing a MAF CEL. (I just bought a '99 S70)

 

My fuel pump and fuel filter have never been changed in the Subaru, and I'm approaching 115,000mi. Is it possible that is my problem?! It makes sense to me.

Bump for answers! Does anyone know where the fuel test port is so I can test the fuel pressure? Is it possible my FPR has gone south also?

Bump again so I can breathe when I drive my car!

 

Service manual states to check fuel pressure, I need to put a gauge in line with the fuel line coming out of the firewall. There is no check port.

 

I have a vag com cable and data logging capability, is there anything I should look for in the data logs when traveling up a hill and the cruise light starts flashing?

 

Hellllllp!