7500 mile car. Mods is sig. SES light shows lean on both banks. Car has all new 02's as of 50 miles ago. The following TECH 1 info was gathered after 4 mile test drive at idle and fuel pressure test was dead on for idle and KOEO test. Why is this thing lean on both banks?

Info from scan tool in Fuel Trim section:
IDLE: 650
ECT: 205 DEG
UNDEFAULT IAT: 86 DEG F
HO2S B1 SEN 1: 61-760
SPARK: 165 DEG 156-167 AVE
AIR PUMP RELAY: OFF
AIR SOLENOID RELAY: OFF
BAROMETRIC PRESS. VOLT: 4.78V
C/C INHIBIT: YES
COLD START UP: NO
CRUISE REQUEST: NO
DTC SET THIS IGN.CYCLE: NO
EVAP CANISTER PURGE: 18%
EVAP CANISTER VENT: NOT VENTING
FT CALL: (BLM): 17%
FT DIAGNOTRIC INHIBITED: DISABLED
FUEL LEVEL REMAINING: 3 GAL
FUEL TANK RATE CAP: 16 GAL
FUEL TRIM LEARN: DISABLED
HO2S BANK 1 SEN 2: 117-833 MV
HO2S BANK 2 SEN 1: 65-812 MV
HO2S BANK 2 SEN 2: 777-820 MV
INJ PWM AVE BANK 1: 2.52-2.79 MS
INJ PWM AVE BANK 2: 2.58-2.82 MS
KNOCK RETARD: 0 DEG
LONG TERM FT AVE B1: 21.9%
LONG TERM FT AVE B2: 19.5%
LONG TERM FT BANK 1: 18%
LONG TERM FT BANK 2: 18%
LOOP STATUS: CLOSED
MIC: OFF
MANIFOLD ABSOLUTE PRESS: 5 PSI
MASS AIR FLOW: 4.67-5.04 GS
SHORT TERM FT AVE: -2.3%
SHORT TERM FT AVE B1: -3.9%
SHORT TERM FT B1: -6.2 TO 5.5% AVE 2.3-3.1
SHORT TERM FT B2: -6.2 TO 5.5% AVE 2.3-3.1

The 10 mile drive home did not result in a new SES light, so I'm not sure what to expect.
The above readings where after swapping my ported MAF for a employee's ported MAF. His MAF resulted in 2-3 % points drop in Long Term FT %'s, and his car is a 99.

Also, we did a vaccume leak test with propane, and nothing showed up.

Any info or translation would be much appreciated, and I will watch the post frequently tonight as to answer any questions anyone may need to ask.

Thanks,
Kurt

 

You can easily cause a lean condition by having a vacuum leak after the mass air meter. Does your lid seal well to the MAF? If you have an egr is it sealing properly? Possibly header leak at the collectors?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by felton316:
<strong>You can easily cause a lean condition by having a vacuum leak after the mass air meter. Does your lid seal well to the MAF? If you have an egr is it sealing properly? Possibly header leak at the collectors?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for the reply. We check everything with propane, and nothing was found. The MAF is sealed real good, and my car has no EGR. The header leak may be something, but I would think that would show some KR, and there is none.

 

Try putting a stock MAF back on to see if your LTerms come back under control.

Some factory cars are already lean when they come from the factory. When you add a ported MAF it takes them to the LTerm limit (25%) and a lean SES is set.

Worth a try....

What is the history of the problem. When did it show up? After engine work, new mod??

 

A header leak doesn't necessary show KR. Header leaks, however, are typically isolated to one bank.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>Try putting a stock MAF back on to see if your LTerms come back under control.

Some factory cars are already lean when they come from the factory. When you add a ported MAF it takes them to the LTerm limit (25%) and a lean SES is set.

Worth a try....

What is the history of the problem. When did it show up? After engine work, new mod??</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for the reply NoGo. I will take your advice on the MAF swap to stock and recheck.
This problem showed up after running a ton of NOS, and finally having a piston skirt let go. I had that all fixed, and all 02's replaced, and now lean all the time.

 

Plans are set to do the MAF swap tomorrow for a stock one. Let you guy's know the results tomorrow. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

i hope the swaps works out good for you that way i get a ported maf

<small>[ November 05, 2002, 11:26 PM: Message edited by: 1BAD02WS6 ]</small>

 

Well...I think I will end up with a stock MAF. The car ran pretty well with the stock meter, and the FT's where down to 0% with a stock MAF in place. Good call you guy's, that has been the problem. I'm not syre what the DA was Fri night or last night, but Fri. night on a 2.0 60' it ran 105.6 MPH and a 13.13 was it's best. At first I was a bit down on the deal since it appeared to loose some HP, but the weather was alot worse DA wise than the night it ran 12.97 @ 107. I have found like most of you all that little difference's in weather ie. DA readings can make a big difference in how these cars run.
MAybe it will suprise me with another 12 sec timeslip with the stock MAF on a better weather night. Last night it went 13.09 with a touch lighter driver, with a DA of like 2,200.(yuck)

Thanks again for the reply's and help. This is a killer source for no nonsense info on thes cars!

Kurt