Engine Light again Chevy 8.1

[garyb1st]

Took the Pace out for a test drive yesterday.  First time since service center cleaned the mass air flow sensor and K&N air filter (washed and re-oiled) 2 weeks ago.  Engine light illuminated after maybe 20 miles.  Same as before.  No drivability issues during the 75 miles on the highway.  By way of background, a couple things that may be related. 

First, mileage on the motorhome during the 20,000 miles we've had it has always been in the 5.5 - 6.5 range.  Even while traversing Midwest minimal hill country at 60-65 mph.  That's after adjusting mileage for generator use.  Usually I adjust at about .6mpg for every hour of use. 

Second, it can take quite some time to downshift during minimal hill climbing, maybe 3-4% grades.  From time to time, I've had to take my foot off the gas and let it slow a bit before it would downshift. 

 

[Mark_K5LXP]

What codes does it show?

Mark B.
Albuquerque, NM

 

[garyb1st]

Code = PO 332.  This is same code as last time. 

 

[Goodspike]

I've heard reports of K&N filters causing issues if they are not oiled properly, perhaps related to MAF sensors (not sure).  You might want to find the code and then search for that and K&N.

 

[garyb1st]

I've read that as well.  The service center agrees that improper oiling can be a problem and assured me it was done correctly. 

 

[Goodspike]

I've read that as well.  The service center agrees that improper oiling can be a problem and assured me it was done correctly.

Ignoring the "new post" warning this forum gives, I posted that response before reading the code you gave.  It doesn't seem like that could would pertain to the filter.

https://obdstation.com/p0332-obd2-code/

 

[John From Detroit]

*I too googled engine code PO 322

When a P0332 code is stored, the most common causes are:

A faulty knock sensor
A fault in the knock sensor circuit or its connectors
An air/fuel ratio that?s too lean
A problem with the cooling system

The Air/Fuel mix should be under computer control but a clogged injector might cause "lean"
Cooling system.
Electrical issue (bad connection)
Bad sensor
Very cheap fuel

 

[PJ Stough]

You need to check the fuel trim. If your engine is running lean, it could damage your engine in a relatively short period of time.

 

[garyb1st]

You need to check the fuel trim. If your engine is running lean, it could damage your engine in a relatively short period of time.

Paul, I'm not familiar with fuel trim so may be reading this incorrectly.  Our Torque OBD - STFT1 read -1.6 to +.8. at idle.  Also, the Torque has a number of different gauges for fuel trim and I'm not sure how they differ. 

 

[garyb1st]

Very cheap fuel

I'm in California.  We don't have cheap fuel.    However, the fuel in the Pace is 10 months old.  I've read that can be a problem. 

 

[Arch Hoagland]

garyb1st said:

"I'm in California.  We don't have cheap fuel."

AMEN!!!

 

[Heli_av8tor]

Oh, you have cheap fuel, you just pay a lot or it!

 

[Lou Schneider]

Oh, you have cheap fuel, you just pay a lot or it!

Amen.  When I was driving from WA to the Bay Area my gas mileage would drop by 10% on the first tank of gas I bought in CA, then would return to normal after I filled up with non-CA gas on the way back.

Oxygenated fuel only reduces emissions in vehicles that are running rich and have a constant air to fuel ratio like from a carburetor.  There were a significant number of these on the road when oxygenated fuel was introduced, but today all modern cars constantly monitor the mixture.  Unless they have a bad oxygen sensor they continuously adjust the air to fuel mixture to stay at the optimum 14:1 ratio.  Adding oxygen compounds to the fuel only makes them inject that much more fuel into the mix with oxygen from the fuel replacing the free oxygen from the atmosphere.

 

[garyb1st]

Oh, you have cheap fuel, you just pay a lot or it!

We have special fuel.  It's formulated to make lots of money for the oil companies.  The State doesn't do too badly either. 

BTW, did you ever get your low fuel mileage issue figured out?   

 

[Heli_av8tor]

More or less. All my effort increased it about 15%. Guess that's significant.

 

[penman39]

I had an issue with my 8.1L having some drivability issues. I put new plugs and wires on and gapped the plugs at .045 based on recommendation from others instead of the .060. and the engine has been running fine and the long and short fuel trims look good too. Maybe it will help you too.

https://www.irv2.com/forums/f22/8-1l-spark-plugs-41-101s-gapped-045-a-208465.html

 

[garyb1st]

Update on the engine light. After researching the On-line anecdotal info I told my mechanic to replace the foam filter with a paper filter. That seemed to work. In 3,000 miles since the change no engine light. Also, I think the mileage has improved somewhat. Over the past 1,000 miles running with the dash air on and the generator running one house AC I've seen between 6+ and 7 mpg. That's also at 60 and 70 mph. The best was 7.5 but that was heading SW from Santa Fe. If you haven't done that, it's mostly down hill.

 

[TheBar]

Thanks for the update. I get an engine light that only stays on for a mile or less every hour or so, sometimes never. The stored code says it was running lean but everything checks out ok and it runs perfect. It never occurred to me but maybe air filters were more restrictive back when it was built. The computer only has a limited range of adjustment.

 

[Lou Schneider]

Update on the engine light. After researching the On-line anecdotal info I told my mechanic to replace the foam filter with a paper filter. That seemed to work. In 3,000 miles since the change no engine light. Also, I think the mileage has improved somewhat.

Good move, Gary. The paper filter also does a better job of filtering out dirt and debris than the foam filter.