Ive posted this before and I do apologize, the difference now is that I have removed my supercharger and upgraded my 4.8 to a 5.3. First of all I have not had my truck retuned, with that said, I drove my truck to my buddies house and then home for total of 55-60 miles, well a little before I get to my buddies house the check engine light turns on and it gives me a p0174 and p0174 code. On my way home the code cleared on its own however the next day I drove her another 30 miles and my check engine light turned back on and has not came off since. I have several questions, first of all do you all believe that my check engine light is caused by not having a retune and second can a bad fuel pump be the cause of those codes? I am sorry for the long essay, its just driving me crazy. Thanks in advance, and happy new year to all.

 

P0174, fuel trim system, lean bank 2. Did you mean P0171 for the first code? That is the same, but bank 2.
If both of your codes were lean, then yes, a fuel pump could of course do that.
Otherwise, did you switch injectors with the engine? That would throw the tune way off.

 

Thank you, that is what we suspect, tomorrow we will be checking the fuel pressure. Oh yea sorry I did mean P0171 for the first code. I did not switch injectors, well bigger once at least, we found a good and cheap complete new intake, with fuel rails, injectors, sensors, throttle body etc and swapped it out, but it was the same number injectors. Our theory is that when the fuel pump warms up after driving for several miles it starts to act up, I do not know how valid that theory is but we will find out tomorrow if its a bad pump. Would the tune affect anything?

 

You are going from a supercharged 4.8 tune and running a stock 5.3?

If the tune is set for the bigger injectors for the supercharger the injector pulse width may be shorter causing the stock injectors to be causing the lean condition

But also could be the fuel pump or filter too

 

yeh, I would bet the problem is the tune. Retune for new injector sizes (and cylinder mass)

 

The tune was set for stock injectors, I was not running to much boost so the stock ones were enough for the s/c.

 

Well the fuel pressure came back normal, the only thing left is to swap out the mass air flow sensor, the light turned off on its own, is it possible there is a short somewhere?

 

If you're using the 4.8 PCM then you need to RE Tune
5.3 has a larger cylinder and it will be fueling for a 4.8 meaning it's running lean.

 

go get a retune first, as stated above. that will tell you everything... i would do that before throwing a bunch of parts at it, just to get it tuned later and fix it.....

 

Thank you all for the replies, I am still kinda new at this so anytime a motor swap is done a tune/retune is required, correct?