Lean Conditions....

H

HNIC57

Member
Joined
Nov 3, 2007
Any input would be appreciated - I am experiencing lean conditions at WOT. Here are some of the things I have done to try and figure out the problem after replacing my rusted out gas tank. Replaced the injectors, fuel filter, fuel pump & sock and the AFPR. I have made sure all vacuum lines are connected and zipped tied. I have checked the fuel lines (feed & return) for leaks and crimps to the best of my ability. In addition I have made sure the lines are properly placed that sit on top of the tank. I even went so far as to blow through the vent line when I had the tank down.
The pump appears to be working as it should be because I am getting 1:1 ratio when I'm in WOT according to the extra long fuel pressure gauge hooked up to the windshield. According to powerlogger and my review of previous data runs; all the data appears to be normal with the exception of my 02 Mv going to 000 upon acceleration (have a WB but need a new sensor); ending in the high 700 range with about 16# of boost. At a lost on what to check next.
 
Probably be helpful to post the power logger file here so others can look at it. Not sure I understand when you say your O2 mv goes to 0 upon acceleration but ends in 700. If you are at idle or slowing down it would make sense to see 0 but when your foot is in it I would expect it to react quickly and end up at 750-800 as you get close to 16 psi. What chip are you using?


Sent from my iPhone using Tapatalk
 
What's your base fuel pressure?

Whos chip?

Replace your 02 sensor. Get a WB sensor so we can see whats really going on.

Whats your WOT tps voltage.

Post a data log

Sent from my SM-G935T using Tapatalk
 
ScottHeidinger said:
Probably be helpful to post the power logger file here so others can look at it. Not sure I understand when you say your O2 mv goes to 0 upon acceleration but ends in 700. If you are at idle or slowing down it would make sense to see 0 but when your foot is in it I would expect it to react quickly and end up at 750-800 as you get close to 16 psi. What chip are you using?


Sent from my iPhone using Tapatalk
Click to expand...
....in absence of a WB (just need to replace the sensor because they go bad quick if you get them too rich); I pay attention to my 02 sensor readings. Historically, when the car was running good my 02 mv readings would be in the low 800's; but they would never drop to single digit and zero readings upon acceleration.
 
Sounds like a bad O2 sensor. I still have my original wide band sensor so there may be a issue with where yours is mounted. I would start with a new O2 sensor since they are cheap. If you've run pig rich it may be covered in carbon giving you the inconsistent readings. Nothing wrong with being cautious about running lean but I wouldn't try to run too rich either. Make sure you turn wide band correction off if you're running a 6.1 TT chip without the wide band working


Sent from my iPhone using Tapatalk
 
Boost231 said:
What's your base fuel pressure?

Whos chip?

Replace your 02 sensor. Get a WB sensor so we can see whats really going on.

Whats your WOT tps voltage.

Post a data log

Sent from my SM-G935T using Tapatalk
Click to expand...
My base fuel pressure is 43# and it is a TT chip. The other modifications to the car are in my signature. Forgot to mentioned I also replaced the 02 sensor. My TPS voltage before gets up to about 2.25 V, before I back off (Max V is about 4.0 if I remember correctly). I also getting some minor knock retard which is indicative of lean conditions. I will try and post my last data log and shop for a sensor tonight.
 
ScottHeidinger said:
Sounds like a bad O2 sensor. I still have my original wide band sensor so there may be a issue with where yours is mounted. I would start with a new O2 sensor since they are cheap. If you've run pig rich it may be covered in carbon giving you the inconsistent readings. Nothing wrong with being cautious about running lean but I wouldn't try to run too rich either. Make sure you turn wide band correction off if you're running a 6.1 TT chip without the wide band working


Sent from my iPhone using Tapatalk
Click to expand...
my WB is actually mounted in a straight pipe down where the catalytic converter used to be. The 02 sensor is new and you're probably right about the WB being covered in carbon (I hear once that happens you might as well get a new one. I have a bunch of old ones lying around). I will also have to look into the wide band correction issue. Never thought of that.
 
ScottHeidinger said:
Probably be helpful to post the power logger file here so others can look at it. Not sure I understand when you say your O2 mv goes to 0 upon acceleration but ends in 700. If you are at idle or slowing down it would make sense to see 0 but when your foot is in it I would expect it to react quickly and end up at 750-800 as you get close to 16 psi. What chip are you using?


Sent from my iPhone using Tapatalk
Click to expand...
...Here's the latest data log. Hope I uploaded it right....lol.
 

Attachments

  • 8-27-17.dat
    167.9 KB · Views: 53
Your MAF seems to be reading kind of low but I'm not familiar with the Extreme G chip calibration.
 
mikestertwo said:
Your MAF seems to be reading kind of low but I'm not familiar with the Extreme G chip calibration.
Click to expand...
The car idled fine and ran pretty good other than being lean at WOT. I also checked the MAF numbers from other data runs and they were pretty consistent; however it turned out that the MAF was indeed the problem when I changed it with a known good one. Thanks for nudging me in the right direction. I really would not have given the MAF much thought. Hope this helps someone else that might be having a similar problem. Now to the "Parts for Sale" section.....
 
I see in your sig you were/are running a LT1 MAF is it the older aluminum body style or newer plastic style?
 
The tune is actually rich. BLM is at 124 at idle and 114 when your cruizing . ECM is pulling fuel.
800mv @ 16* is pretty much on target. 000mv when you lift the throttle is not uncommon.

What wideband? Do you have the wideband hooked to the gen 2? Is wot tracking on? What are your settings? You might want to make sure the gain is set to 0 if the wideband is messed up. Need to get that fixed.

I can tune the that thing to run very well with that gen2 and extreme G chip. That's a sweet set up. Way under rated.

Did you buy the car with the the gen 2 installed?
 
HNIC57 said:
...Here's the latest data log. Hope I uploaded it right....lol.
Click to expand...

This is what i see after a quick look.

Log looks pretty good, the knock your getting is on the 2/3 shift which happens and its not even 1deg its .07

02 sensor voltage does look odd but when your under throttle it appears to be working as it should and i dont think this is your issue

this is what i think you should do next.

Go out somewhere where you can run the car in 3rd gear and roll into it. We don't want it to kick down into second so don't stab it and dont go to slow.

Make sure you log your run and post back..
 
You must log in or register to reply here.

Similar threads

1KWIKSIX
Fuel Line Heat Shield & Hardware
Replies
7
Views
217
1KWIKSIX
1KWIKSIX
Toddmc66
Fuel pressure too high. Cut off the end of the return lin.
Replies
8
Views
399
dynoman
dynoman
E
Weird Gas Tank Problem
Replies
4
Views
440
edfiero
E
C
No fuel
Replies
5
Views
496
hensleyt
hensleyt
NoVA_87_GN
Scanmaster data
2
Replies
23
Views
2K
THensley
T
Top