Thread: Well how about that? Running lean

Like P10FTW said, get a fuel pressure guage, that is really bad o_0

Contrary to popular belief, the UEGO doesn't need to be free-air calibrated prior to installation. They come calibrated from AEM. His AFR's reported are likely accurate, depending on location of install. Having it installed near shifter linkage would have it reporting just fine, so we can rule that out.

Get a FPR gauge and monitor fuel pressure as you drive around. If the fuel pressure doesn't increase as load increases, then I'd suspect the FPR first. It's also cheaper to replace than the fuel pump.

The ECU is a basic daughterboard

I could borrow a gauge from a friend and get it into the cabin temporarily

I always suspected of the pump even before the swap, the car ran slow for a healthy DE (175 compression across) and the lack of power up top, when I did the swap this was my first VVL and wasn't impressed at all, took it to the strip and low 15's, I'm glad now I know what's the potential reason and that the car could run tons better as soon as fixing the gas issue.

Just for the record, there's this hill on my way home from work and when my gas is below 1/4 tank it bogs for a second

I would pull the pump and check the filter and basket. If the filter sock has tons of residue it could prevent the pump from pulling enough fuel properly, as well.

Spoke to a tuner and he told me this would be software related, maybe my TP scale is not right and the ECU is not at the last rows where the gas for WOT is.

I think this is a hardware issue, however I am gonna try burning a couple of bins

If u can just run a MAP trace and see for yourself. To me it still sounds like the pump

By far the cheapest option ^. Could still very well be the pump, but burning a bin is free. If you're not under full load when driving around do the AFR's stay decent, or do they still go stupid lean? For instance, if you're at highway speeds and drop to fourth and keep the rpm's steady, does the AFR take off higher?

I would send you a few bins, but I don't know if I have any B14 bins for VE's. I can take a look for you though.

I've never done a datalog using Nistune but my friend who is a tuner told me to do it so i could realize if the TP scale is off

As far as tools I got a Blazt cable, Datascan, Tunerpro, burner and tons of blank 27SF512's

So do I Cory, I think the fuel pump has seen better days and that would be the reason of the lack of power up top

Cliff I could realy use some extra bins to compare and wouldn't hurt try a couple more

Thnx for the input

You don't need to use nistune. All you need is the blazt cable and nisdatascan and do a map trace. You'll know right away if this tuner is on the right page...

Did you double check to make sure the daughter board isn't coming lose? and X2 reburn the rom and check again could have gotten corrupted. I had a problem like yours with my Nistune board but it was a user error AKA ID10T tho lol.