P0171 ONLY on the H2
 

So of course its only been a couple of weeks since the o2 sensor issue has been fixed with the new PCM. I also just got the pesky TPMS light to go away with a new sensor. And I know better than to fix everything and to always leave one thing broken otherwise the car gods would haunt me.

This time I have a p0171 code. That's it, no other code. Everything was good until 2 days ago, I even towed the can am up in the north Georgia mountains. Then, a few days after, the light popped up, I thought it was probably just a fluke so I cleared it, and it came back the next day after driving for a while. It then cleared itself after a few key cycles yesterday.

I did some logging in HPTuners, and from what my inexperience can tell, it looks like Bank 1 is running pretty lean. Under heavy throttle 75-80% and WOT, if I look at the LTFTs for bank 1 and bank 2, they seem to be far off from each other. As in Greater than 20 % at some times. Bank 2 will say around -5 - -7 but bank 1 will say +20 - +25. Again, not an expert, but that seems abnormal. They are only about 1-2% off during idle and light acceleration.

The thing that's got me is that its only a bank 1 code. There are no obvious vacuum leaks that I can see, and those would likely set a p0171 and p0174 for both banks. Also, the truck seems to run just fine. I'm not sure if it could maybe be an injector, cat, a tuning issue, or the new tune just needs to adapt to the truck. I would expect 2 weeks and 300 miles+ would be long enough for it to learn driving habits.

I'll upload the log file when I get home tonight and do a little more driving today to see If I can get the light to come on while I log data. And if anyone is not familiar with my previous posts it is an 08 with a TVS1900 Magnuson supercharger.

I'm no expert on these things but the lean code with a supercharger could mean your stock fuel pump can't deliver the required fuel at certain times? I've read others had this issue as the diameter of the fuel line in certain places is to small to allow the proper amount of fuel to be delivered when running a supercharger or bigger turbos. Again, just throwing out ideas.

Could also be the factory fuel injectors are not capable of proper fuel delivery.

It has upgraded injectors. Found that one out the hard way trying to run it for even a little while with the factory tune. And I've heard about the issues with fuel pressure with the 03-07 models, but I heard on the 08, the factory fuel pump is much better.

Here are three different hptuner log files if anyone is interested. I have never shared these before, so let me know if there's issues opening them.

https://drive.google.com/file/d/1oYh...ew?usp=sharing
https://drive.google.com/file/d/1acQ...ew?usp=sharing
https://drive.google.com/file/d/1tfF...ew?usp=sharing

Side note, engine light stayed off all day today and I drove quite a bit.

Ill also add this is a new problem. Its been supercharged for 6 years with no problem. The only recent change is the PCM recently and the transmission over a year ago.

Update: I made a smoke machine following this guy's tutorial...

I ended up actually finding a leak somewhere around the snout of the supercharger. It looks like it's coming directly out between the snout and the pulley. However it's hard to tell since it is tight up there by the two tensioners. It could be coming from the gasket at the bottom of the case. I might end up taking it to someone or buying a better smoke machine to know for sure.

I'll bet your H2 is an absolute blast to drive......6.2L with a maggy, wow!

It's certainly somethin. When it works that is. I think this years summer project is pulling of the supercharger and sending it to be rebuild. That way it'll be fresh and I can put all new seals in. its been on for 6 years and 40k miles. Not a ton of miles but a lot of heat cycles.

I'll just keep updating even if there's no interest. Hopefully it will help someone.

Recap of everything
-p0171 code only
-hp tuners shows really lean condition on bank 1 and slightly on bank 2. Sometimes bank 1 drifts way away.
-smoke testing revealed a leak at the pulley of the s/c which I didn't even know was possible, but I double checked, and that's where its coming from
-I did some research and found that ls motors tend to run more lean on the drivers side than on the passenger due to the firing order. That is why with a vacuum leak, if small, will only throw a p0171 and not a p0174.
-Magnuson contacted me back and said with 40k miles its not worth sending it for a rebuild and to just replace the bearing in the snout and reseal it.

This summer, I'll rebuild the snout, or get a rebuilt one, get new gaskets and o-rings for the intake, and replace the one leaking valve cover. I'll report back with results when its all done, and hopefully this solves my rattling noise at 3k rpm which i expect to be some sort of knock, and if not, I just wont worry about it anymore.