anyone ever had this happen to them blm wise?

[1500chevy5.7l]

ok so blms were doing great staying great at 125-128 mostly 127-128... then as i got low on ags i mean really low like riding on the "E" for a wile.... my blms got richer and richer were at idel i was 111... and cursing was 119-120... and wot was 125... why would less gas in the tank cause rich condition? why would it cuase anything? i would think less gas mean lean.......

[91chevZ71]

have you refilled it and checked your BLM after?

[1500chevy5.7l]

not yet low on funds to till tuesday...lol.......

[HaulnA$$]

ok so blms were doing great staying great at 125-128 mostly 127-128... then as i got low on ags i mean really low like riding on the "E" for a wile.... my blms got richer and richer were at idel i was 111... and cursing was 119-120... and wot was 125... why would less gas in the tank cause rich condition? why would it cuase anything? i would think less gas mean lean.......I can think of a couple of reasons off the top of my head but it is probably a combination of things. One reason is that with less fuel sloshing around in the tank, there is more room for vapors to be created which are then introduced into the intake charge via the charcoal cannister purge. The second reason is that the fuel in the tank actually keeps the fuel pump cool. It is possible that as your fuel pump heats up a little the fuel pressure goes up as well. Not too likely, but possible. You must also remember that TBI trucks do not use an air temp sensor. Compensation for changes in incoming air temp are done via BLM's. I think it is probably a combination of two or more of these things and not just the fact that the tank is low. HTH

[1500chevy5.7l]

well i am about to fill up...lol...but its got to be ebcuase i am low cuase most of the time my blm at idel is 127 now today when i think i almost ran out it hit "99" at idel not sure why it does this still i would think that less fuel would cause a lean condition but i guess not will update after i fill up...

[1500chevy5.7l]

ok well even after filling up.... bam still hitting 117 to 114 blm in closed loop at idel but as soon as i start to move it goes to 120 to 125 to 127 but idel bam.... like even when i am crusing at like 1200rpm its at like 118 blm the odd part is all was fine till i ran low on gas....it never did this before any insight on to what happend?.....:dunno:

[91chevZ71]

could be a pinhole exhaust leak or something like that. intake leak, etc, tbi gaskets

[1500chevy5.7l]

well the only thing i did before all this happend( but it only started when i ran low.. super low on gas) was cleaned my msd wires to give back that shiney red to them.....and re torque my tbi mounting bolts..wich ended up needing like 1/4 of a turn each.....for safty reasons i check every 6k(two oil changes) my bolts to make sure...but all was fine tune has been great wot and crusing are 127 to 128 but at idel and like 600 -2000 rpm i am at 119blm and at dead idel i am 114 or lower sometimes........any idea....

[pfk]

Did you recheck your fuel pressure just to make sure everything is within spec?

[1500chevy5.7l]

yes its exactly 13psi on the gauge......