everythings cool til i floor it

[heath26]

when i floor it about half way through third my engine light comes on the codes are 131 137 151 157 (o2 sensors) and once that happens the fuel loop closes and the torque converter wont lock up any ideas anyone. i have checked the eng sen fuse it is good

[blackSS01]

when i floor it about half way through third my engine light comes on the codes are 131 137 151 157 (o2 sensors) and once that happens the fuel loop closes and the torque converter wont lock up any ideas anyone. i have checked the eng sen fuse it is good

O2's going to hell maybe

[heath26]

O2's going to hell maybe

all 4 at the same time kinda funny i think but i guess you never know

[0rion]

what are your mods?

[heath26]

what are your mods?

slp loud mouth,air lid and a slp maf but i know what your gonna say the codes were poping up before it,i just got it back from trans shop last week it had been over there for about 2 months

[0rion]

was it doing anything before the visit to the trans shop? Kinda odd you would get all 4 showing low voltage like that at the same time.

[cammed goat]

Maybe a re-tune is in order?

[heath26]

it was doing it before the trans but that wasnt the first trans i shelled and i didnt want to take it to the tune shop again til it was running right. unless the tune can take it out?

[cammed goat]

Our cars don't really like aftermarket MAFs. That might be the cause.

[0rion]

have you checked your fuel pressure and for vacuum leaks and things like that? Might get the easy stuff out of the way early.

[Cutlass]

Here's some ideas from the GM Service manual:
• The PCM sets this DTC when the vehicle runs out of fuel.
• Heated Oxygen Sensor (HO2S) wire: Sensor pigtail may be in contact with the exhaust manifold or the exhaust system.
• An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provides the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination.
• Test for intermittent ground in signal wire between connector and sensor.
• Lean injector(s): Perform the Injector Balance Test.
• Fuel contamination: Water near the in-tank fuel pump inlet can be delivered to the injectors. The water causes a lean exhaust and can set a DTC.
• Fuel pressure: System will be lean if fuel pressure is low.
• Exhaust leaks: An exhaust leak near the HO2S can cause a lean condition.
• Vacuum or crankcase leaks can cause a lean condition.

[heath26]

have you checked your fuel pressure and for vacuum leaks and things like that? Might get the easy stuff out of the way early.

how do you check the fuel pressure i was hoping my scan tool would show it but it didnt and whats the best way to check for vacuum leaks

[0rion]

how do you check the fuel pressure i was hoping my scan tool would show it but it didnt and whats the best way to check for vacuum leaks

you'll have to buy a few pressure gauge ( ~$20 and make sure you get one that'll fit GM cars) and on the end of the drivers side fuel rail there's a cap. Remove that cap and there's a shrader valve there. Should have ~58psi.

Vacuum leaks you can check with carb cleaner or propane. Idle the engine and spray down the hoses and listen for the idle to change. Before you do that though check the pcv hose going into the throttle body on the passenger side. It likes to crack on the back side of that elbow.

[heath26]

you'll have to buy a few pressure gauge ( ~$20 and make sure you get one that'll fit GM cars) and on the end of the drivers side fuel rail there's a cap. Remove that cap and there's a shrader valve there. Should have ~58psi.

Vacuum leaks you can check with carb cleaner or propane. Idle the engine and spray down the hoses and listen for the idle to change. Before you do that though check the pcv hose going into the throttle body on the passenger side. It likes to crack on the back side of that elbow.

fuel pressure at 58 even when its to the floor or should it go up im gonna try to get enough hose to run it up somewhere i can see it when im driving to see what it does under load

[Too Fast]

Yes the pressure needs to stay at 58 throughout WOT accelerating. I wish I had a wiring diagram handy to see if all the sensors have a common wire. It could be that when you floor it, the engine moves just enough to short a wire that all the O2s have in common. They switch ok below and above 450 mV during normal driving?

[heath26]

Yes the pressure needs to stay at 58 throughout WOT accelerating. I wish I had a wiring diagram handy to see if all the sensors have a common wire. It could be that when you floor it, the engine moves just enough to short a wire that all the O2s have in common. They switch ok below and above 450 mV during normal driving?

i dont know switching i cant watch the scanner and keep it on the road at the same time i just know that when i floor it all the sensors start reading between 30 and 50 mv and after 30 seconds of that it trips the code the fuel loop closes,the converter wont lock and the car runs like junk

[Too Fast]

^^^Well if it really is that lean then you have a problem. That is way lean and should be fixed promptly. Under full acceleration, the upstream O2s should always be around ~900 mV.

Could still be a wiring issue, on the signal return wire to the PCM. That's why I said I wish I had a schematic handy, to tell you which wire it may be that is grounding/shorting.

[heath26]

^^^Well if it really is that lean then you have a problem. That is way lean and should be fixed promptly. Under full acceleration, the upstream O2s should always be around ~900 mV.

Could still be a wiring issue, on the signal return wire to the PCM. That's why I said I wish I had a schematic handy, to tell you which wire it may be that is grounding/shorting.

running around town they are always 800 to 900 mv and i found a wire diagram on gear chatter and there is one wire that controls all of them its a pink wire #539 the more i think about it the more i think its the fuel system not the sensors you would think that a big bump would shake things around enough to make it short but it never does only when you floor it

[heath26]

just been cruisin town not runnin the car hard at all my engine light comes on and now it giving 171 174 (lean bank 1 and 2) no vac leaks that i can find and i remember hearing my fuel pump gets loud after long trips like 150 200 miles straight. didnt throw the o2 sensors this time

[Cutlass]

it might be that SLP MAF
Lean on both banks could be a MAF problem, low fuel pressure, or vacuum leak.