92hatchLX

So I scanned my motor tonight and I've got 2 lean codes 41 and 91 (left and right banks running lean). I've pretty much ruled out the MAF, tested it and swapped it for another one and I'm still getting lean codes. I'm going to replace the fuel filter tommorrow, it hasn't been changed in a year and a half. What else should I check? It seems that when sensors start going bad, they cause the motor to run rich, but that is not the case now. Anyone have any suggestions if the fuel filter swapdoes not work?

Joel5.0

Things suggested to check:

- Vacuum leaks (do you have an open breather installed with a functional PCV valve?.....if so, there's a vacuum leak)
- Fuel pressure (with and w/out vacuum line connected...should be over 35 psi)
- HEGO ground wire condition and contact behind driver's side cylinder head (Orange colored wire)
- Exhaust leaks
- PCV Valve
- O2 sensors

Blckstng93

Those codes are for the o2 sensors. get new ones.

creekrat

The codes mean the O2 sensors are getting a reading outside what they are supposed to get. This can be caused by other things as well as bad sensors! Do not replace them unless you are sure that they are defective bu ruling out everything elce! Unless you just want to throw parts at it and hope that one will fix the problem!

Blckstng93

Good point Creek. Now that i actually think about it, it does seem a bit coincidental that both sides are lean at the same time. My bad. Been a looong day for me.

92hatchLX

I've checked for vacuum leaks and that's almost what it seems like the issue is, but I couldn't find any. I just got done replacing the fuel filter and I'm letting the computer reset as we speak. I've got good fuel pressure at idle though. The HEGO wire connection (the terminal that it uses to bolt onto the head, so I replaced the terminal and grounded it to the back of my intake manifold, will this cause any issues? I can't find any exhaust leaks, pcv valve is new and the 02 sensors only have about 30000 miles on them. I'm going to go double check that HEGO ground wire right now.

adumb

alright i am going to sound wicked stupid but i have to ask.... you just randomly decided to scan your car for codes. how do you do this and what do i need to buy in order to do it.

92hatchLX

I bought a code reader from o'reilly's. It makes life a LOT easier. It was only $20

92hatchLX

Okay so I got rid of codes 41 and 91 by moving my HEGO ground from my intake manifold, backto it's original location (on the back of the cylinder head), and replacing my fuel filter.My motor seems to be a lot more responsive, I can't drive it around right now though, it's been raining like cats and dogs and theroadsare waay too muddy. Now I'm getting code 45 which is a thermactor air upstream. What would trigger this one?

Joel5.0

You could also DIY with a paper clip and a 12-vdc test light (if the CEL doesn't work).