Guys, I have a 04 350z with Vortech Version 2 tuner kit that was tuned with Uprev. The problem that I'm facing recently is whenever I cruise uphill and I step on my gas paddle half way down, my air fuel ratio will run really lean to 17-18. This happens at around 3k rpm when it tried to build to boost. When this happens, I either tries to give a quick tap on my paddle and the ratio will jump back to 12-13, or I will let go of the gas peddle and go really slow. The car runs fine on flat, or downhill. It felt as if not enough gas is going to the engine when cruising, but normal under heavy load. I hope I explained this well enough, but I will try my best to provide more information if someone points me to the right direction.


Thanks

 

likely hitting a section of the map that isnt seen very often and isnt really tuned, it happens unfortunately and if uprev tuned it they should fix it.

 

higher load in lower rpm range. one of the perks of Speed Density tuning that you dont encounter this.

 

^ If your tuner didn't address the high load/lower RPM cells then it will happen to you no matter if it tuned on MAP or MAF.

When you say " give a quick tap" do you mean give it more gas?

 

If the tuner doesn't tune it correctly or at all in that RPM/load area on the 2D fuel map you have the same issue. MAP or MAF it doesn't matter. I think what you might be noticing is that there's more bonehead/lazy Uprev tuners specializing in N/A bolt-on tunes (and their F/I tunes end up like this), than Haltech/ProEFI or other MAP based tuners who do F/I much more often.

 

can I ask a stupid question here - how do you know and/or what instrument are you taking your information from to come to the conclusion that you are running lean? is it off a laptop w/your tuning software or is it off a stoich gauge?

The reason I ask is my procharger installer back in 2007 tuned my car off my a:f ratio gauge and it was horribly wrong…at WOT I was running a 18:1 when I dyno'd…my point here is if you are reading off a a:f ratio gauge you may want to get a second opinion.

 

^ I'm guessing he's logging with cipher. '04's have dual OEM widebands.

 

I can only assume, op didnt mention and it may be a load : rpm culprit, but I like to start easy and work to hard…

we shall see...