P0174 Code (only, no other codes)

[jfl330]

Ok I've been chasing this issue for a long time. Brief rundown of things done:
Pulled intake, checked gaskets, removed and resealed bottom plate on BBK SSI intake, replaced entire PCV system, changed O2 sensors

I pulled plugs from pass side and all 4 completely fouled (black), driver side are fine.
Bench tested front O2, ran up to >0.9V then down to almost 0 quickly.
Front O2 reads 40 - 50mV all the time as soon as it goes closed loop. Tried another O2 and same results.

Any one have an idea I can try?

Jon

[cammed goat]

Have you tested the voltage on the throttle position sensor? That could be on its way out. I think 174 is a lean code in bank #2. Possible low voltage from the TPS. I could be wrong. I had this code with my car a few months back. Turned out to be a combination of a weak TPS and disconnected #5 cylinder plug wire.

[0rion]

Ok I've been chasing this issue for a long time. Brief rundown of things done:
Pulled intake, checked gaskets, removed and resealed bottom plate on BBK SSI intake, replaced entire PCV system, changed O2 sensors

I pulled plugs from pass side and all 4 completely fouled (black), driver side are fine.
Bench tested front O2, ran up to >0.9V then down to almost 0 quickly.
Front O2 reads 40 - 50mV all the time as soon as it goes closed loop. Tried another O2 and same results.

Any one have an idea I can try?

Jon

have you checked the O2 wires to make sure nothing is shorted? Doesn't sound like that's your issue but another place to look. Checked the a.i.r. pipe gasket on that side for a leak or any exhaust leak before the front O2? Also could be a stuck valve for the air system on that side. Try swapping those valves side to side and see if the problem follows it.

[jfl330]

have you checked the O2 wires to make sure nothing is shorted? Doesn't sound like that's your issue but another place to look. Checked the a.i.r. pipe gasket on that side for a leak or any exhaust leak before the front O2? Also could be a stuck valve for the air system on that side. Try swapping those valves side to side and see if the problem follows it.

The AIR system is removed, but I re did the seal under the block-off plate as it looked suspect. Also changed all the o-rings on the injectors. The O2 sensor voltage is normal prior to going closed loop so I doubt it is a short issue.

Thanks for the suggestions, I will post the results of yesterdays work after I take it for a drive later.

Jon