Red97GT

So since last time at track I added SSRA ram air extension to my SLP ram air, put UMI Lca's on
and I P/P T.B.

Perfect night for racing 40% humidity and upper 50's temp's

So first pass. 13.81@101.2 w/2.06 60'ft
next pass 13.72@ 102.4mph w. 2.15 60'ft

during second pass SES light came on. So I left track knowing something is wrong.
Last time at the track I ran 13.07 and 13.08 back to back hot lapping on a 70% humidity upper 70deg day.

Get home and scan code p0131 02 sensor low volt bank 1 sensor 1
02 reading 0.09-0.11 does this seem correct?????
would this pull timing and make it slow. drove 20 miles home and seem to run fine with plenty of power. I even drove 500 miles to LS Fest with P/P TB with no issues

Did I getting to much air from SSRA lean it out??. Or vacuum leak??
I did not change TB gasket when I removed it. Vacuum line from TB to intake looks good.
Or do I have a bad 02 sensor? What should a good 02 read??

any advise would be very helpful
Thanks "mods in sig"

Red97GT

Update.
Cleared codes and did some WOT pulls and data log.
P0131 & p0151 showed up. I only had p0131 yesterday. Bank 1& 2 sensor 1
Was reading 0.02- 0.92 02 voltage.
Is it possible port and polish tb can lean out 02's
Im way over my head when it come to tuning

2xLS1

iTrader: (25)

No

What were the O2s mv showing only at WOT. Guessing were you were logging with a Predator. Any way to export the log so it is post-able like maybe in an excel file format?

Red97GT

2xLS1 i dont have cable to export file.
Looking at log file WOT was 0.04 for both 02's and 0.92 as soon as i let out of throttle.

I replaced TB gasket and vacuum hose from TB to intake and still throws p0131 & p0151. it hasnt thrown a hard fault SESlike yesterday, but when I scan it is there.
only does it when i pull WOT pulls.
What would lean out a 02 sensor 1???

2xLS1

iTrader: (25)

Low fuel pressure, air leak downstream of the MAF, Any air getting into the engine that doesn't go through the MAF sensor. There isn't a vacuum line from the TB to the intake. There is a fresh air hose that runs from the throttle body to the front port on the passenger side valve cover.

Red97GT

What should fuel pressure be?? Should I change fuel filter and check pressure?

Will a Diablo read fuel pressure?

OOH I replace a fresh air line. Well that make sense.

I did have a very low tank of fuel when I was at the track. I dont know if i was just freaking out but I could have sworn it sounded like the fuel pump was louder on the way home from track. I didnt notice that today.

2xLS1

iTrader: (25)

FP s/b 58 psi.

Red97GT

Just checked Diablo. It wont read fuel pres.
So is 58psi constant pres.?

So it makes sense if im putting a ton more air into engine (ie p/p tb and ssra) and maf is reading it and trying to adjust fuel trims but pressure is insufficent.

If the MAF was bad it would give a diffrent OBDII code?

Car seems to run fine. I have been beating the **** out of it today and it pulls like crazy. But the 1/4 mile time and SES tells the real truth..

Red97GT

Update.
Today I changed fuel filter and put some fuel system cleaner in.
Data log showed 0.03mv @ WOT on both banks 1&2 sensor 1. And throw codes again.
Cleared codes and drove home and drove it normal and not going WOT. checked codes and none were there. So it only throws codes at WOT

2xLS1

iTrader: (25)

You are probably seeing .03v which is 30mv. O2s reading 30mv at WOT is extremely lean. They should be around 900 mv. (.900v) Put a fuel pressure gauge on the rail with a long enough hose to tape it to the windshield and check the FP at WOT. Or you could keep blindly throwing parts at it and keep putting junk in the fuel.

Russ K

iTrader: (1)

Most likely a bad Maf. Just unplug it and see if the 02's go to 800+ mv @WOT. If they do, then just replace the Maf, if not then test the fuel pressure at WOT.

Russ Kemp

Red97GT

Will a GM Tech II read fuel pressure?
I work for a car dealership. I willl talk with a couple of techs to see who has a gauge that will hook up to the rail.
I was seeing 0.15v at idle. It would jump all over the place. Highest i saw was 0.89. Does this seem normal?

Red97GT

I didnt data log maf. If maf is bad would it set of a code to?
What should a good maf be reading while logging?

Russ K

iTrader: (1)

Seen many bad Mafs that didn't set a Maf code. Maf Hz will be ~3000 at idle to 9500+ at WOT & redline. And the more power the engine makes, the higher Hz.

Russ Kemp

Red97GT

Just went out and checked 02s at idle with maf pluged in was .15-.09 unpluged it jumped around from.89-.04. Cant go do WOT pulls right now.
I did have maf off when i ported TB

2xLS1

iTrader: (25)

O2s switch between 100mv and 900mv continuously in closed loop idle and part throttle. That is how they maintain 14.7:1 A/F ratio by going above and below 450mv. There is no FP sensor on a 00 F-body.You have to use a pressure gauge on the rail.

Red97GT

Update.
Fuel pressure 60 psi at start up. Wot first gear pull. Psi38# 02's drop to .05

Unpluged maf while logging for
Second pull wot 1st thru 2nd gear. 35psi thru 2nd gear
02's start at .87 then drop quick to .06
So fuel pressure is to low. Pump going bad?

Russ K

iTrader: (1)

Since your fuel filter is new, you need a new fuel pump. The pressure shouldn't go lower than ~54 psi @wot at redline.

Russ Kemp

2xLS1

iTrader: (25)

And if you are going to replace the pump with an OEM style then use only an AC Delco. Stay away from auto parts store off brand pumps especially Airtex.

Red97GT

Thanks for the help guys.

Sucks I have to do a fuel pump and racing season weather is perfect right now.
I better go shopping and see if I can pick up a pump.
Do I have to drop the tank to put pump in??

Thanks again I will update when pump install happens.