P0172 , + stalling at the lights...any other idea?
- Thread starter djtc
- Start date
I'm thinking another injector is stuck open or maybe the maf or upstream o2 is bad but I can't imagine them causing it to dump enough gas to cause white smoke. It's p0172 so bank 1 so could I just put the old injectors back in on that side (and hope I don't grab the one that was clogged before, unfortunately I didn't mark them) or could too much fuel on either side cause that code?
Any other ideas on what it might be?
I did break a couple bolts on the last reinstall, even though I was using a torque wrench set to 13 ft lbs, maybe its way off somehow, but the last time it did this none if the bolts were broken or anything and the 2 that broke seem like they're not totally vital, although I obviously need to get new ones, one on the upper plenum and one on the throttle body, they still seem to be sealed and I'd get a lean code if they were letting air in right?
Any other ideas on what it might be?
I did break a couple bolts on the last reinstall, even though I was using a torque wrench set to 13 ft lbs, maybe its way off somehow, but the last time it did this none if the bolts were broken or anything and the 2 that broke seem like they're not totally vital, although I obviously need to get new ones, one on the upper plenum and one on the throttle body, they still seem to be sealed and I'd get a lean code if they were letting air in right?
19963.4lsr5
New member
All 6 cylinders are bank 1.
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Sent from my iPhone using Tapatalk
thegipper
New member
Here is my experience that I had recently with the P0172 code:
My truck started to run rough and actually died when I pulled into a parking lot. It seemed down on power, idled rough especially on a cold start up and just felt sluggish. My check engine light never came on but when I scanned it, I had a pending P0172 code.
Fast forward to what I replaced/fixed:
I replaced the upstream O2 sensor with a new Denso unit. I had to drop the CAT because both nuts on the O2 sensor were seized on and that's when I found a crack in the pipe, outside of the O2 sensor flange.
I welded the crack shut and installed the new O2 sensor. It's been running great ever since and I've picked up a couple MPGs. This was a few months ago so the problem was definitely fixed (no more code either).
Unfortunately, I don't know for sure if it was a bad O2 sensor or if it was from the crack since I fixed both at the same time.
My truck started to run rough and actually died when I pulled into a parking lot. It seemed down on power, idled rough especially on a cold start up and just felt sluggish. My check engine light never came on but when I scanned it, I had a pending P0172 code.
Fast forward to what I replaced/fixed:
I replaced the upstream O2 sensor with a new Denso unit. I had to drop the CAT because both nuts on the O2 sensor were seized on and that's when I found a crack in the pipe, outside of the O2 sensor flange.
I welded the crack shut and installed the new O2 sensor. It's been running great ever since and I've picked up a couple MPGs. This was a few months ago so the problem was definitely fixed (no more code either).
Unfortunately, I don't know for sure if it was a bad O2 sensor or if it was from the crack since I fixed both at the same time.
Thanks for the experience there, I've been thinking maybe o2 sensor but I can't imagine an o2 sensor causing enough extra gas to make white smoke, from my understanding it's black smoke unless you have like waaaay to much gas and mine is definitely white but doesn't smell like coolant at all, smells like gas or maybe a little like gear oil.
Is there any way it could be the fuel pressure regulator without gas in the vacuum hose or maybe the fuel pump or do I keep swapping injectors and see if they fix it?
thegipper
New member
The upstream O2 sensor is literally the only way the computer knows if it needs to adjust the fuel trim levels post combustion. A bad O2 sensor can most certainly cause the computer to think that it needs to add a lot more fuel when it actually doesn't or vice versa.
I found a really good write up (not on this site) that explained how the whole air/fuel system on a modern vehicle works when I was trying to diagnose my problem. I'll see if I can find it.
It should also be noted that an O2 sensor can be bad without throwing a code.
19963.4lsr5
New member
In my experience that is so true. If the heater circuit fails it codes. If the sensor starts screwing up it hardly ever codes until you’ve gassed your oil from running rich all the time.
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ok, my '00 4runner 2wd v6 auto started running ruff when accelerating, P0301 code (cyl. 1 miss), replaced all 3 coil pacs, all wires, 6 plugs, 6 injectors (injector in cyl. 1 came out in two pieces, literally), and ran great for 10 min, then CEL back on, idle never dropped from 1200, throwing P0172 code (sys too rich bank 1 - which is bank 1, dr or pass?). I let it sit overnite, again drove around the block, CEL stayed on, parked and plugged in a CAN OBD2 little red scanner and pulled the following information:
DICFR2F P0172 and CEL
FUEL SYS 1 CL
FUEL SYS 2 NA
LOAD PCT 18.4
ETC 178
SHRT FT1 -20.3
LONG FT1 -19.5
RPM 795
VSS 21
IAT 86
MIL STAT OFF
MISFIRE MON OK
FUEL SYS MON OK
COMP COMPON OK
CAT MON INC
HTD CAT NA
EVAP SYS MON INC
SEC AIR SYS NA
A/C REFRIG MON NA
OXY SEN MON INC
OXY SYS HTR OK
EGR SYS NA
Then i cleared the codes, CEL went off, drove again around the block a couple time, and no CEL, and no codes, and 790 idle. I am a believer in Toyota greatness, but come on, a self-repairing car? Any ideas? And what does a flashing CEL mean? receiving codes, or what?
DICFR2F P0172 and CEL
FUEL SYS 1 CL
FUEL SYS 2 NA
LOAD PCT 18.4
ETC 178
SHRT FT1 -20.3
LONG FT1 -19.5
RPM 795
VSS 21
IAT 86
MIL STAT OFF
MISFIRE MON OK
FUEL SYS MON OK
COMP COMPON OK
CAT MON INC
HTD CAT NA
EVAP SYS MON INC
SEC AIR SYS NA
A/C REFRIG MON NA
OXY SEN MON INC
OXY SYS HTR OK
EGR SYS NA
Then i cleared the codes, CEL went off, drove again around the block a couple time, and no CEL, and no codes, and 790 idle. I am a believer in Toyota greatness, but come on, a self-repairing car? Any ideas? And what does a flashing CEL mean? receiving codes, or what?
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