Fst_Byrd

iTrader: (5)

I have a 99 trans am ls1, headers, exhaust, ported throttle body and fost mail order tune.

I have recently installed a racetronix fuel pump and wideband o2/gauge in my car. I feel like my a/f ratio moves around A LOT

On initial startup, my a/f ratio moves around from like 13.5-15 once it idles down or drops around 14.2-15.
Light cruising it bounces all over from high 12's to 16 and if I hit WOT its all over the place, usually bounces around from 12's to mid17's then goes full lean and displays "---"!!

At first I had a fueling issue, but I believe that is fixed. I have pressure tested the fuel at the rail and I'm getting 58-61 psi as idle, also hady buddy read the gauge while I break torqued it to about 3000rpm and it sat at a solid 60psi the whole time.

Also had a small exhaust leak at my collector before sensor and fixed that(the a/f was reading pretty lean at idle before that was fixed)

Is my car really running this lean!?!? Or is there an issue with the gauge??

Please help me with any ideas of what's going on here! I'm not driving the car anymore since there's a chance its really this lean.

From the few times I have driven it, it idles smooth, as it always has and feels just as powerful as it always has, no sputtering, no surging, can't here pinging...


Thanks

Old Geezer

iTrader: (3)

How do the wb and nb sensor readings compare?
Where is the wb mounted?

Fst_Byrd

iTrader: (5)

I'm not sure how to take reading from the narrowbands. I don't have any tuning software...which is the only way I know to view operations of the stock narrowband o2.

I have my wideband on the drivers side after the collector/stock o2 and before the hi flow cat. They are edlebrock longtubes so its about 26" from the exhaust port on the cylinder head...not home at moment but I can get exact distance later tonight if necessary.

Fst_Byrd

iTrader: (5)

Also forgot to mention, I did throw a code for "evap purge solenoid low output" not sure what that means yet..and not sure that effects this situation at all.

Fst_Byrd

iTrader: (5)

Anybody have ideas?! Is this a bad WB o2? Did I screw up wiring?

Fst_Byrd

iTrader: (5)

I'm really thinking this is a wiring issue. I pulled my spark plugs and they look and smell perfect thus making me believe I'm not like really leaning out!
I have the hotwire for the wideband hooked into one of those add-a-circuit things and it shares the spot with the 10amp "gauges"correct or not. on the dash fusebox, I believe its spot number 9.

I feel like I've read before that the wideband must be hardwired all by itself...not sure if this is correct or not but would like some input.
Also the grounds for all 3of my gauges (WB, FUEL AND BOOST) are all on the same ground location which was a spot under the dash panel behind/under the steering wheel..could my ground cause the gauges to act odd? I knowy fuel pressure is about 10psi off from what my gauge I put on the rail reads.


Just thinking to myself outloud on here but can't make it to car to work on it for few days do figured I'd ask some more questions


Thanks

Slowhawk

iTrader: (12)

Unplug the MAF and do a WOT pull. If it's close to correct it is a bad maf. It will not throw a code for that.

Fst_Byrd

iTrader: (5)

If the a/f on the gauge is close?..to what...around 12.5 for WOT?

Fst_Byrd

iTrader: (5)

I unplugged the MAF and it idles very lean, floats around 17-17.5. Scared to actually do a WOT run that lean, I just revved it in the driveway to about 3200rpm and a/f drops to low-high 13's. Does that seem right or do I actually have to go WOT with MAF unplugged on the street?


I also think I ruled out the wiring or the WBO2. I pulled put the WBO2 and it reads full lean, and took a BIC lighter and sprayed the butane on the tip of the WBO2 and it went full rich (a/f of 10).

Fst_Byrd

iTrader: (5)

Also have realized that sometimes when at idle its around "stoich", 14.5-15. Other times it idles a little richer in the low-mid 13's range...this change happens withoute changing or adjusting anything...just happens.

Fst_Byrd

iTrader: (5)

To the top for help please!

Old Geezer

iTrader: (3)

Help involves some data logs and posting the tune............

Fst_Byrd

iTrader: (5)

I know that would help, but I don't have any means for data logging and I really don't think its the tune.
Its the same tune I have had for a little over 2 years when I got my mail order tune from Frost. I doubt he would have set me to run this lean, and as hard as I've driven my car...going this lean, my engine would have been toasted by now.

Fst_Byrd

iTrader: (5)

I swapped in a new Bosch 17018 wideband sensor and that didn't help...
Checked for vacuum leaks and found zero...fixed small exhaust leak...

Still have nothing. I just ordered a obd2 reader so I can read the fuel trims and o2 sensor voltage and all those goodies ...

BUT! Until then if anyone had some ideas....I'm begging

redtan

iTrader: (5)

Sounds like a tune issue. Well not an issue perse, just the lack of "fine-tuning" of the tune. A tuner halfway across the country with a laptop is not going to know how your car will react to a tune that he just came up with on the spot. Without logging the car and fine-tuning the results over and over again to perfect the parameters you will always have such large swings in fueling and other things.

Basically what you need is a tuner that can actually drive the car and see what changes it needs, then making those changes and starting all over to see what else needs to be done. Till then, what you have is a "guess" of a tune.

Also, I would not be driving that car hard until you can fix the tune. Anything over 13.5 at WOT for a short period of time is going to be catastrophic for your engine.

Fst_Byrd

iTrader: (5)

So I'm getting my obd2 reader today. What should I be looking for in scope of my o2 sensor voltages, maf readings fuel trims and what not?