P0171 and P0420 code problems
01-23-2023, 06:08 PM
#1
Member
Thread Starter
Join Date: 08-09-2020
Location: tampa bay
Posts: 92
P0171 and P0420 code problems
so glad i don't live in commiefornia anymore... i've had the p0420 code since i bought the car 30K miles ago and still haven't gotten around to replacing the cat - i see see plenty of after market ones on ebay for about $100 -
have done lots of other maintenance and repairs over that time but just last week i got the P0171 code and now the car is currently dead while i find time to troubleshoot it. I'm reading posts first and running tests before asking the community for ideas if i don't solve it.
have done lots of other maintenance and repairs over that time but just last week i got the P0171 code and now the car is currently dead while i find time to troubleshoot it. I'm reading posts first and running tests before asking the community for ideas if i don't solve it.
01-23-2023, 06:23 PM
#2
Administrator
Join Date: 10-13-2011
Location: Welland,Ont Canada
Posts: 36,580
Clean the MAF sensor, check for cracked exhaust manifold, check for broken flex pipe
https://www.obd-codes.com/p0171
https://www.obd-codes.com/p0171
01-23-2023, 08:34 PM
#3
Member
Thread Starter
Join Date: 08-09-2020
Location: tampa bay
Posts: 92
btw, would it be normal for a fuel pump to die suddenly or would one expect to have signs one is failing?
I am wondering this tonight before checking a few other things tomorrow like a defective evap canister that i replaced fairly recently, the flex pipe for leaks/cracks, the MAF connector for short/ MAF cleaning. Because prior to no turning over at all, and before the 0171 code showed up, car ran great. Always the same - first time starting up would almost always start the second time, then while driving throughout the day it'd always start the first time with no fuss. Gas mileage has been awesome - 30-33 on highway at 55-60 even awesome.
The day before this happened, car was running/driving fine as usual. Then next morning it would start up then stall immediately. Did this 3 or 4 times and that's when the code showed up. Went online to see what it might be. Looked for vacuum leaks etc, couldn't find any. That's when i discovered i had killed the battery to the point that it would just click-click... click-click... so went and got the battery slow trickle charged at the store - didn't realize battery is 5 years old and they said it was only able to get to about 500amps and /12.4V.
i figured it being weak, i would wait until it warmed up to the 60s/70s again and try to start the car to see if it'd at least do the start/stall deal so i could determine if i had inadvertently fixed it. Starter would do it's thing but engine wouldn't fire up.
So I went to rent a fuel pressure gauge. attached gauge - turned key to ON (battery still has enough power to run accessories. Pressure gauge stays at zero, but when i removed the gauge i got sprayed with some gas so clearly there was SOME pressure and I may not be doing something right as i've never used a fuel gauge before but it seems pretty straight forward.
Due to my gas gauge being faulty, and now a weak battery I am wondering is the car out of gas? the initial problem was the car would start, then immediately stall, and now the battery is done.
A few years ago when i didn't realize the gas gauge couldn't be trusted, i ran out of gas. So I wonder if maybe 1. battery needs to be replaced regardless. 2. my car could be out of gas / sonmeone siphoned my tank overnight (I have my suspicions)
It's really going to suck if it turns out to be the fuel pump because I can't work on my car where I live (at least not for that job)
I am wondering this tonight before checking a few other things tomorrow like a defective evap canister that i replaced fairly recently, the flex pipe for leaks/cracks, the MAF connector for short/ MAF cleaning. Because prior to no turning over at all, and before the 0171 code showed up, car ran great. Always the same - first time starting up would almost always start the second time, then while driving throughout the day it'd always start the first time with no fuss. Gas mileage has been awesome - 30-33 on highway at 55-60 even awesome.
The day before this happened, car was running/driving fine as usual. Then next morning it would start up then stall immediately. Did this 3 or 4 times and that's when the code showed up. Went online to see what it might be. Looked for vacuum leaks etc, couldn't find any. That's when i discovered i had killed the battery to the point that it would just click-click... click-click... so went and got the battery slow trickle charged at the store - didn't realize battery is 5 years old and they said it was only able to get to about 500amps and /12.4V.
i figured it being weak, i would wait until it warmed up to the 60s/70s again and try to start the car to see if it'd at least do the start/stall deal so i could determine if i had inadvertently fixed it. Starter would do it's thing but engine wouldn't fire up.
So I went to rent a fuel pressure gauge. attached gauge - turned key to ON (battery still has enough power to run accessories. Pressure gauge stays at zero, but when i removed the gauge i got sprayed with some gas so clearly there was SOME pressure and I may not be doing something right as i've never used a fuel gauge before but it seems pretty straight forward.
Due to my gas gauge being faulty, and now a weak battery I am wondering is the car out of gas? the initial problem was the car would start, then immediately stall, and now the battery is done.
A few years ago when i didn't realize the gas gauge couldn't be trusted, i ran out of gas. So I wonder if maybe 1. battery needs to be replaced regardless. 2. my car could be out of gas / sonmeone siphoned my tank overnight (I have my suspicions)
It's really going to suck if it turns out to be the fuel pump because I can't work on my car where I live (at least not for that job)
01-23-2023, 10:38 PM
#5
Member
Thread Starter
Join Date: 08-09-2020
Location: tampa bay
Posts: 92
yes i am aware the gas gauge is part of the pump.. sometimes it's accurate, sometimes it's not so i don't trust it. But based on my odo and how much gas i put in it last it should currently still have several gallons in it - unless as i mentioned, someone siphoned it out during the night.
according to everything i have been reading on here and elsewhere, P0171 can be caused by lots of different things, including the fuel pump which is why i asked is it typical for a pump to suddenly fail without warning? (besides the gauge being unpredictable for the last 15-20K miles.
according to everything i have been reading on here and elsewhere, P0171 can be caused by lots of different things, including the fuel pump which is why i asked is it typical for a pump to suddenly fail without warning? (besides the gauge being unpredictable for the last 15-20K miles.
01-24-2023, 06:41 AM
#6
Administrator
Join Date: 10-13-2011
Location: Welland,Ont Canada
Posts: 36,580
Can you hear the fuel pump prime when you turn the key on? The pump pressure test gauge read 0? Did you relieve the pump pressure at the fuel rail? 12.4 volts is a dead battery, put some fuel in the tank and try it.
01-24-2023, 06:42 AM
#7
Senior Member
Join Date: 12-05-2014
Location: Northern Ohio
Posts: 2,375
The trouble with ignoring a code that sets the CEL is that you won’t notice a new code.
Any chance someone pumped E85 or even E15? Anything more than E10 will screw up a non-Flexfuel fuel pump. Failure could be sudden or not. But a failed level sensor is one of the most common problems caused by ethanol in the fuel. (Source: GM fuel system expert.)
Your 2006 2.2 has very small injector orifices that are notorious for clogging. That could cause the P0171. Crud from a corroded fuel pump or lines would be an explanation. There is no fuel filter. P0420 could be from corroded lines.
Any other codes? Have you tried some injector cleaner?
PSA - I’m told the Flexfuel fuel pump is backwards compatible. When replacing one, get one listed for a Flexfuel year as well.
There is a TSB for the P0420. Not terrible useful, just lists all the places to look for an evap leak. There are many.
Any chance someone pumped E85 or even E15? Anything more than E10 will screw up a non-Flexfuel fuel pump. Failure could be sudden or not. But a failed level sensor is one of the most common problems caused by ethanol in the fuel. (Source: GM fuel system expert.)
Your 2006 2.2 has very small injector orifices that are notorious for clogging. That could cause the P0171. Crud from a corroded fuel pump or lines would be an explanation. There is no fuel filter. P0420 could be from corroded lines.
Any other codes? Have you tried some injector cleaner?
PSA - I’m told the Flexfuel fuel pump is backwards compatible. When replacing one, get one listed for a Flexfuel year as well.
There is a TSB for the P0420. Not terrible useful, just lists all the places to look for an evap leak. There are many.
01-24-2023, 11:43 AM
#8
Moderator
Join Date: 01-23-2009
Location: Fredericksburg,VA
Posts: 24,736
My point being: there has been warning of a failing fuel pump, the gauge is not accurate. My guess would be a loose wire.
Easy to check if the pump has anything to do with a P0171/P0172. Fuel pressure test, high might cause rich low might cause lean.
Better to start your own thread than to find a thread with dubious relation to hijack, then we all know what we are talking about without rereading 3 pages of previous unrelated posts..
Easy to check if the pump has anything to do with a P0171/P0172. Fuel pressure test, high might cause rich low might cause lean.
Better to start your own thread than to find a thread with dubious relation to hijack, then we all know what we are talking about without rereading 3 pages of previous unrelated posts..
01-24-2023, 12:35 PM
#9
Member
Thread Starter
Join Date: 08-09-2020
Location: tampa bay
Posts: 92
didn't mean to hijack the thread but oldblue chimed in after my first comment and i caved in and went into details... not as experienced with forum etiquette (47 posts on here compared to your 22,925 posts)
other forums i'd been on would scold people for maknig a new post on same/similar things assuming they couldn't do a search first. I appreciate the help everyone gives and strive to be civil and helpful on a forum.
That said, would it be better for me to create a new post from here on out or can a moderator edit this one and make the part where i started into a new post?
Forums are a great source of info, but the way they are designed leaves much desired.
Off to get a new battery, get a gas can and put some gas in to make sure there's definitely gas in the tank and report back later.
Pulp - yes i got some FI cleaner last night and put it in the tank. no other codes besies 0171 and 0420... of course now with the battery having been taken out, all the codes have been erased.
other forums i'd been on would scold people for maknig a new post on same/similar things assuming they couldn't do a search first. I appreciate the help everyone gives and strive to be civil and helpful on a forum.
That said, would it be better for me to create a new post from here on out or can a moderator edit this one and make the part where i started into a new post?
Forums are a great source of info, but the way they are designed leaves much desired.
Off to get a new battery, get a gas can and put some gas in to make sure there's definitely gas in the tank and report back later.
Pulp - yes i got some FI cleaner last night and put it in the tank. no other codes besies 0171 and 0420... of course now with the battery having been taken out, all the codes have been erased.