COLDZ71

iTrader: (2)

I have posted some of these questions in the FI section but it is kind of a seperate subject now. I just installed a side mount Magnacharger on my truck with the Magnacharger tune. I am now getting codes p0131 and p0151. I have cleared them twice but they come back after heavy acceleration. Once the ses light comes on the truck runs horrible. Usually missing and sputtering. I didnt think it was supposed to do that when the ses light comes on. I noticed this evening that the drivers side exhaust manifold has a broken bolt at the very front and there is a little blow by. Can this be causing the codes? What else could be causing the codes? I will be fixing the exhaust manifold no matter if it is the problem or not. I really need to get this thing running right and I have a laptop with autotap if I need to log anything so please reply. Thanks.

COLDZ71

iTrader: (2)

Anyone have any suggestions? Anything I should be aware of while I am already working on it?

budhayes3

iTrader: (19)

Those codes are O2 sensor low voltage codes for each bank correct? So the PCM is seeing a lean condition for whatever reason, that is effecting both banks. I'd be checking for some form of vacuum leak or unmetered air entering the system. I believe that once the CEL illuminates with a powertrain code like that, the PCM will go into limp mode, which may explain why it runs differently once the CEL has illuminated.

99Silver6.0

iTrader: (1)

That broken bolt can be a problem too if its leaking. Cold, fresh air can be introduced there. When that air hits the sensors itll really throw things off. Might want to see what you can do to fix that bolt.

Log your O2's with ATAP. Go hit on her hard and be sure your recording the whole time shortly before and during your WOT run. That way you can see what your O2 millivolts do. If they dip down fairly low at a high RPM, your getting lean or that fresh air is hitting the front O2.

COLDZ71

iTrader: (2)

I am going to fix the broken bolt and replace the exhaust gasket tonight. If I still get a code then I will do some logging to see what is up with the front 02s. Thanks for the input guys.

ktmrider

How do the LTFT and STFT look? If they are +5 or higher your engine is asking for more fuel than can be provided. The injector duty cycle will also be a good barometer, over 85% in any area usually means bigger injectors needed.

COLDZ71

iTrader: (2)

I am quite new to this. Can you please explain what LTFT and STFT. I will be logging with AUTOTAP if that helps with any of your suggestions. Thank you for the help.

ktmrider

Sorry about that. STFT = Short Term Fuel Trim, LTFT = Long Term Fuel Trim. In a nutshell it uses feedback from the emission control system to adjust the amount of fuel sent to the engine to maintain an "optimal" air/fuel ratio and lower emission output. The LT is coarse ( measured and adjusted over a longer period of time ) and the ST is fine ( nearly real time ). A plus (+) indicates the computer is adding more fuel than would normally be required and a minus (-) is removing. The LT gathers data and acts as the baseline or standard while the ST makes corrections based on a variety of outside conditions and engine operation ( cold, hot, poor fuel, rain, etc ). Target your trims to +/-3, with the blower I would aim for 0 to -3 ( slightly rich ).
If you are using the stock O2 sensors ( referred to as narrow band ) I would keep an eye on the injector duty cycle ( how long the injector squirts fuel ). Anything near or over 85% means the computer is sending more fuel than is "normal" or expected. If you have a wideband O2 to monitor the air/fuel ratio see if you are going lean. I would target between 11 and 12:1 a/f under boost.
I see you are in Maine. Do they require ethanol based or oxygenated fuels in your area? If so this could be a big reason for the lean condition. Also cold air can cause a lean condition ( denser oxygen concentration ).
Good luck, hope you work out the problem!

COLDZ71

iTrader: (2)

If I can watch the fuel trims on AUTOTAP I will surely take a look at them. I am interested in seeing what they say. I do believe that they use oxygenated fuel up here in the winter. I run 93, is there anything else I can do to combat the shitty fuel? I am heading out at the moment to the garage, I will post the results of fixing the exhaust leak.

COLDZ71

iTrader: (2)

Dammit!! Still getting the same codes even after I fixed the exhaust leak. After being warmed up for about 10 minutes was cruising around and the light came on at only 1/4 throttle. I was accelerating and it came on at about 60 mph. Anything else I should look for besides my fuel trims? I am going to try and get a laptop to log the truck this weekend.