p0171 lean code from hell
11-11-2016, 12:00 AM
#11
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Were all of the parts replaced in an attempt to resolve the primary concern, being no engine power?
If not, it would help to know when specific parts were replaced, and if it was in an attempt to resolve the issue.
I mainly ask because many of these are parts that won't usually cause a loss of power (unless you count a dead engine a power loss).
Also, what specifically was replaced when you did "the basics" and when? You never even mentioned anything of the sort in the original post.
I am mainly trying to get a bit more context on what is where, that'* all. For example, I am nearing 9 years of ownership on my '93 PA. In that time, a fair amount of parts have been replaced, some of which have been replaced an annoying number of times. I could list all of the parts when troubleshooting an issue, but once I put everything in context, most will realize the parts replace have no bearing (and in turn no meaning) to the issue at hand.
I try not to assume, because, well, you know...
If not, it would help to know when specific parts were replaced, and if it was in an attempt to resolve the issue.
I mainly ask because many of these are parts that won't usually cause a loss of power (unless you count a dead engine a power loss).
Also, what specifically was replaced when you did "the basics" and when? You never even mentioned anything of the sort in the original post.
I am mainly trying to get a bit more context on what is where, that'* all. For example, I am nearing 9 years of ownership on my '93 PA. In that time, a fair amount of parts have been replaced, some of which have been replaced an annoying number of times. I could list all of the parts when troubleshooting an issue, but once I put everything in context, most will realize the parts replace have no bearing (and in turn no meaning) to the issue at hand.
I try not to assume, because, well, you know...
I've done spark plugs wires harmonic balancer, crank positioning sensor, ignition control modular, fuel pump, needed be changed anyways it was low on fuel pressure when I bought the car 11 months ago and everything has been changed recently too from 3 months to 11 months ago also did a mass air flow sensor and a cam sensor witch the sensor at the time was bad or on its last leg I thought that was the issue at first because I had zero power and when I was going uphill it was chugging and bucking so it needed it anyways regardless it does run better with it replaced but not like it should still no power
11-11-2016, 08:41 PM
#15
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When live data is scanned, also look at which cylinders are misfiring. That will give you a ton of information there as well, pointing to an injector, coil, or something else.
Also unplugging the MAF sensor and going for a test drive (without flogging) will be another interesting point of data, because that will cause the engine to run under a different set of parameters.
Also unplugging the MAF sensor and going for a test drive (without flogging) will be another interesting point of data, because that will cause the engine to run under a different set of parameters.
11-16-2016, 11:36 AM
#16
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well i just wants to keep u all informed. that i cant get any shop time until next week my buddy is slammed at work and i checked all the common vac leaks and im surprised as hell because there isn't 1 and for a 1995 i was expecting 1 lmfao. i also checks for stupid issue i found 1 of my spark plug wires laying on top of my oxygen sensor wire so i zip tied to make it not touch. now stupid question the p0171 says in the VERUS its a Fuel Trim System Lean Bank 1 oxygen sensor bank 1 or something like that but it did have oxygen sensor in the fix on the scanner could it really just be that stupid sensor thats causing me all these issues with the loss of power this bad?
11-16-2016, 06:11 PM
#17
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It could be several possibilities.
These may be worth looking through if you haven't already:
https://www.gmforum.com/obd-ii-troub...6/#post1390823
https://www.obd-codes.com/p0171
Basically, the computer is detecting that the o2 sensor is showing too much oxygen in the exhaust. It could be the oxygen sensor, but then again it could also be something else, including bad MAF sensor, bad injector, fuel pump, vacuum leak, LIM gasket leak, etc.
If there is an apparent substantial loss of power as a direct result of the issue, it helps narrow down some of the likely suspects.
As I mentioned, you can unplug parts as part of troubleshooting, as it will force the computer to guess based on the information it has, versus relying on information that'* wrong. When the problematic part is disconnected, the engine will take on an entirely different set of characteristics. It still won't run right, but it will either still have the same characteristics it had before, plus a couple of new ones, or it will be completely different.
I actually narrowed down 2 problematic Ford MAF sensors by unplugging them and driving without them. When unplugged, then engine still had issues, but it was a whole different set of issues.
These may be worth looking through if you haven't already:
https://www.gmforum.com/obd-ii-troub...6/#post1390823
https://www.obd-codes.com/p0171
Basically, the computer is detecting that the o2 sensor is showing too much oxygen in the exhaust. It could be the oxygen sensor, but then again it could also be something else, including bad MAF sensor, bad injector, fuel pump, vacuum leak, LIM gasket leak, etc.
If there is an apparent substantial loss of power as a direct result of the issue, it helps narrow down some of the likely suspects.
As I mentioned, you can unplug parts as part of troubleshooting, as it will force the computer to guess based on the information it has, versus relying on information that'* wrong. When the problematic part is disconnected, the engine will take on an entirely different set of characteristics. It still won't run right, but it will either still have the same characteristics it had before, plus a couple of new ones, or it will be completely different.
I actually narrowed down 2 problematic Ford MAF sensors by unplugging them and driving without them. When unplugged, then engine still had issues, but it was a whole different set of issues.
11-18-2016, 10:14 AM
#18
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Hi Lawrence and rj, I am just now reading this post and now understand why you asked the question in my post (O2 sensors) 
Based on my experience with a very similar issue - lack of power while high fuel consumption - I would say it is definitely worth to check the kat flow and look at the O2 sensors. In my case the downstream sensor was surely not reporting the correct amount of oxygen - I say, much less then actually is in the exhaust stream - which might have prompted the ECU to command too much fuel, hence the engine runs too rich. Since the O2 sensor was sending data it was not causing a code.
I replaced both sensors which much improved the situation of low power and high consumption. Still under close monitoring though. Need to clear the fuel trim history as well when replacing the sensors.
Based on my experience with a very similar issue - lack of power while high fuel consumption - I would say it is definitely worth to check the kat flow and look at the O2 sensors. In my case the downstream sensor was surely not reporting the correct amount of oxygen - I say, much less then actually is in the exhaust stream - which might have prompted the ECU to command too much fuel, hence the engine runs too rich. Since the O2 sensor was sending data it was not causing a code.
I replaced both sensors which much improved the situation of low power and high consumption. Still under close monitoring though. Need to clear the fuel trim history as well when replacing the sensors.
11-19-2016, 05:43 AM
#19
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Hi Lawrence and rj, I am just now reading this post and now understand why you asked the question in my post (O2 sensors)
Based on my experience with a very similar issue - lack of power while high fuel consumption - I would say it is definitely worth to check the kat flow and look at the O2 sensors. In my case the downstream sensor was surely not reporting the correct amount of oxygen - I say, much less then actually is in the exhaust stream - which might have prompted the ECU to command too much fuel, hence the engine runs too rich. Since the O2 sensor was sending data it was not causing a code.
I replaced both sensors which much improved the situation of low power and high consumption. Still under close monitoring though. Need to clear the fuel trim history as well when replacing the sensors.
Based on my experience with a very similar issue - lack of power while high fuel consumption - I would say it is definitely worth to check the kat flow and look at the O2 sensors. In my case the downstream sensor was surely not reporting the correct amount of oxygen - I say, much less then actually is in the exhaust stream - which might have prompted the ECU to command too much fuel, hence the engine runs too rich. Since the O2 sensor was sending data it was not causing a code.
I replaced both sensors which much improved the situation of low power and high consumption. Still under close monitoring though. Need to clear the fuel trim history as well when replacing the sensors.
11-19-2016, 11:26 AM
#20
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this motor maybe shoot i dont know it only has 150k. a old lady owned it so i really have no clue on how hard or how abused it was or if it was just a catastrophic failure. but could a simple o2 make a no power issue sorry if im asking to many ? i have to learn some how