HWFSTRU

I am hoping someone can give me some help here...

I have been out playning in the snow and all of the sudden I got a "Check Engine Light" I went to AutoZone and used their diagnostic hand-held and it told me I had multiple codes (2) for "Lean on Bank 1". Now, I just installed new injectors, fuel rails and fuel pump about 3k ago and haven't had any issues so I am considering multiple possibilities here:

1. Snow, salt and sand got packed in around the O2 sensor possibly causing a false reading.

2. Perhaps it is cold enough that the fuel table in the PCM can't keep up with the cold air; it is currently 5 degrees. ( -10 with the wind-chill).

3. I am hoping this isn't it - I have a one (or multiple) bad injectors on Bank 1.

4. Bad O2 Sensor(s)

What do you guys think? Any help would be appreciated! Thanks

HWFSTRU

No one can help me out here?

Lurius

iTrader: (7)

I got that code the other day, as well as p0101, MAF sensor. We discussed it a moment and came to the conclusion that perhaps I got a wee too much water in my MAF when I ran through a bunch of 2-3" deep puddles(hey, gotta clean those wheel wells somehow!) and it may be causing my MAF sensor to act up and that it COULD effect the engine, making it think its getting more air or something.

Either way I dident clear mine yet and am waiting to see if they go away.. If they dont I will be clearing them in a few days. If they coem abck then I got a problem.

-Lurius

TouchOfEvil04

iTrader: (13)

Sounds like a o2 sensor goin or gone bad. I'd get it cleared and see if it comes back. If it comes back i'd replace the o2 sensor myself.

Lurius

iTrader: (7)

I cleared the codes an hour ago, and aparently bank 2 is lean on mine as well. So we'll see if it comes back, ill post my results. Keep us updated on yours, we both seem to have been doing similar stuff and had similar results, so I dont think its our o2 sensors.

-Lurius

86MC_SS

iTrader: (3)

I had bank 2 lean last week

https://www.performancetrucks.net/fo...d.php?t=383402

No one replied.

I reset the fuel trims and stopped closed and open loop (hp tuners) and revved the truck a couple times and turned the truck off and restarted it and it cleared up on its own.

HWFSTRU

OK so here is what I have for you...

After some time down at my local dealership this is what they tested and the results:

1. Fuel Pressure Regulator - tested - good
2. Fuel Injectors - no low cycles logged - checked - good
3. MAF - no MAF codes, but it has been cleaned and re-installed - checked - good
4. Bad Fuel (maybe) - Tank was almost empty, so filled it up with 93 and they ran some 44k fuel treatment - checked - good
5. O2 sensors - sensors checked out fine and a reading on line with their computer system

So, you may ask yourself, "What the hell is it then?" Well the answer came at us in an unusual manner. The tech had put his nasty hand on my intake (the one on top the motor not the tube and filter assembly) and was cleaning some grease off of it with carb cleaner and guess what happened.... that right... the RPMs jumped. Ding Ding Ding... We have a winner!

(EDIT - you will need to do the carburator cleaner check when the engine is cold, becuase the intake will expand a little with heat. We did the test when warm and did not get the drastic RPM jump... it was almost not noticible).

So basically I need a new intake gasket. Cost at chevrolet for just the gasket is about 100.00, but it is only about 35.00 at AutoZone for Felpro.

I did a little research on this topic and apparently in cold enviorments, the difference in expansion rates between the intake and heads is more noticible; especially on vehicles with higher mileage. The intake leaks allowing the extremely cold ambient air into the cylinders causing a lean condition. You probably would not even notice this in the middle of the summer.

I hope this helps those having the same problem.

Chris

Lurius

iTrader: (7)

Thanks, this does help a lot. Which explains why I only had bank one then now bank 2 today as well. I bought a scanner so I can monitor it without driving to autozone lol. I'll have to go pick up some carb cleaner while im out. Think torquing the intake bolts a little more might help fix it? Im in texas and we rarely get this weather. I just need a temp fix as I will be putting new motor in a month from now and can replace the intake gaskets easier then.

Thanks a bunch! I tried a couple things to no avail today. I did have some fun with some seafoam though! lol

-Lurius

GMCHammer

iTrader: (4)

I have been fighting with my O2 sensors ever since it got cold. Replaced both O2 sensors....Welded up ORY to Pacesetter headers....Cleaned MAF and checked intake tube for leaks....New TR55 plugs....had it re-tuned....and it was still missing down in the lower RPMS and throwing O2 codes....I stopped by Autozone 2 nights ago and put in a bottle of seafoam into the tank and it stopped. I am guessing I have a bad injector or maybe need to replace the fuel filter.

Lurius

iTrader: (7)

Have fun with the fuel filter there lol, its in tank for the 04 models. Might as well upgrade the pump while your in there.

I used some sea foam today as well, maybe it will help,. who knows with that stuff.

How are you guys cleaning the MAF? What should I use to clean it?

-Lurius