P0171 with Landtank's MAF
- Thread starter NLXTACY
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NLXTACY
Wits' End
NLXTACY
Wits' End
- Thread starter
- #44
excellent!! Thanks!
no prob. I actually am looking for smaller cans of it to keep in my tool kit because the next time it needs cleaning I would like to be ready. And a Pep Boys may not be readily available
It is a good feeling to know that all I need to do is pull off the intake hose and give the sensor a few squirts and be good to go again. Of course this is if I am in really dusty areas. But doing it as part of the 3k oil change may negate the need to actually carry it. I dunno.
I had the P0171 Cel come up yesterday and I am getting ready to go through and check everything but I had some of the items on my list to replace for maintanence. I was just curious what Landtanks sleeve is I searched in the 80 section and theVendors Market and really didn't find anything.
I use a small artist brush to sweep the sensing wires gently while I hose them down with the cleaner. This technique has worked well to thoroughly clean them.
I need to try giving the MAF a cleaning based on this...
I've been fighting a P0171 for awhile now. Started with the P0401 and that was resolved after replacement of whatever it is called...Then the 80 popped the O2 codes so those were replaced. But the P0171 will keep coming back. Replaced the fuel filter and the sock and no change.
Checked the other usual stuff listed like the air tube (no cracks etc.) and jiggling the MAF harness and nothing. It is crazy because the fuel trims are PERFECT at everything but idle. At idle they drop just low enough to trip the CEL. Drive around with the AC on in the summer (get that little bump in RPMs at idle) and no code and the truck passes all of the diagnostics per my Scanguage.
I have the MAF mod in both my LX and the 80 but only the 80 is throwing the code - trucks have nearly identical mileage and have had the MAF mod for the same length of time (I haven't installed the sleeves yet though)...Next on the list was sending the injectors out for cleaning...
Annoying code for sure
I've been fighting a P0171 for awhile now. Started with the P0401 and that was resolved after replacement of whatever it is called...Then the 80 popped the O2 codes so those were replaced. But the P0171 will keep coming back. Replaced the fuel filter and the sock and no change.
Checked the other usual stuff listed like the air tube (no cracks etc.) and jiggling the MAF harness and nothing. It is crazy because the fuel trims are PERFECT at everything but idle. At idle they drop just low enough to trip the CEL. Drive around with the AC on in the summer (get that little bump in RPMs at idle) and no code and the truck passes all of the diagnostics per my Scanguage.
I have the MAF mod in both my LX and the 80 but only the 80 is throwing the code - trucks have nearly identical mileage and have had the MAF mod for the same length of time (I haven't installed the sleeves yet though)...Next on the list was sending the injectors out for cleaning...
Annoying code for sure
the sleeves reduce the size of the bore and effectively "speed up" the air flow. I would still clean the sensors or at lest swap them between the trucks. But as I've posted, I recommend the sleeves for everyone that have the original housing.
alia176
SILVER Star
This thread is a good place to record P0171 & Landtank MAF sensor so I hope NXLTACY doesn't mind me posting here!
I'm having the same P0171 as Joey with P0325 (knock sensor #1) for couple of years now. Going through my log book, here's what I got recorded:
head gasket r/r, fuel injectors cleaned/balanced - 3/28/08
Fuel filter r/r - 3/28/08
Landtank MAF (no sleeve), FPR capped - 8/1/08
Fuel pump sock filter r/r - 12/27/09
Air intake hose - sometime in 2009?
EGR bypass (resistor on temp sensor, egr mod valve vac hose)- 1/21/10
P171 & P325 - 8/22/10. May have come on before but not logged
P171 & P325 - 10/30/10, 8/10/11, 1/5/12
Things I'll be checking:
- MAF sensor pin connection
- clean MAF sensor
- check for intake air sensor air leakage
- check to see if the exhaust Y pipe crotch is leaking. I TIG'ed it back in 2006. Maybe there's another leak?
- maybe check the knock sensor resistance reading at the ECU to make sure it's still in spec.
Anything else?
I'm having the same P0171 as Joey with P0325 (knock sensor #1) for couple of years now. Going through my log book, here's what I got recorded:
head gasket r/r, fuel injectors cleaned/balanced - 3/28/08
Fuel filter r/r - 3/28/08
Landtank MAF (no sleeve), FPR capped - 8/1/08
Fuel pump sock filter r/r - 12/27/09
Air intake hose - sometime in 2009?
EGR bypass (resistor on temp sensor, egr mod valve vac hose)- 1/21/10
P171 & P325 - 8/22/10. May have come on before but not logged
P171 & P325 - 10/30/10, 8/10/11, 1/5/12
Things I'll be checking:
- MAF sensor pin connection
- clean MAF sensor
- check for intake air sensor air leakage
- check to see if the exhaust Y pipe crotch is leaking. I TIG'ed it back in 2006. Maybe there's another leak?
- maybe check the knock sensor resistance reading at the ECU to make sure it's still in spec.
Anything else?
If you have an OBDII scanner post up what the short term and long term Fuel trim values are. You will likely need to run the truck up to temp first. When added together the acceptable range is -30% to +35%.
alia176
SILVER Star
will do
The description in the FSM seems to contradict itself and the fuel trim numbers would make that clear.
alia176
SILVER Star
Just returned from a drive and managed to capture some data. My OBD-II software has "freeze frame" capability - which is basically a snap shot of all the parameters right when the CEL came on. I also managed to capture couple of screens of O2 readings.
Let me know what you think.
That clears up the question I had with the FSM.
The problem is while you are idling. While idling the FT% total more than +30% however they are at 11% while driving.
Do you have access to a wide band sensor. If the AFR is 14.2 while idling then the O2 sensors are working properly.
The first thing I'd do is check the Air flow rate (AFR) during idle. This should be in Lbs/Min and with an unsleeved housing it should be around .68-.70 lbs /min. If it is then the MAF sensor is reading properly and the issue is somewhere else.
The problem is while you are idling. While idling the FT% total more than +30% however they are at 11% while driving.
Do you have access to a wide band sensor. If the AFR is 14.2 while idling then the O2 sensors are working properly.
The first thing I'd do is check the Air flow rate (AFR) during idle. This should be in Lbs/Min and with an unsleeved housing it should be around .68-.70 lbs /min. If it is then the MAF sensor is reading properly and the issue is somewhere else.
alia176
SILVER Star
According to screen shot #2, AFR at idle is 0.6 lbs/min
Sorry, no wideband access unfortunately.
Sorry I missed that. Is the FPR is still capped?
That AFR reading is slightly lower than what I recorded but not enough to account for the large FT%
I'd suggest sleeving that housing and reattaching the vacuum line afterwards as a first step. The sleeve will bring the idle AFR back in line with the stock sensor.
I posted a series of data logs a while ago here https://forum.ih8mud.com/80-series-tech/347736-obd-ii-data-logs.html
If you look at the unsleeved logs you will see that the AFR is as lows as .63 during idling but the FT% never gets very high with the exception of a non sleeved housing with an attached vacuum line to the FPR.
I wonder if it has something to do with the fuel pump relay being in the low position.
That AFR reading is slightly lower than what I recorded but not enough to account for the large FT%
I'd suggest sleeving that housing and reattaching the vacuum line afterwards as a first step. The sleeve will bring the idle AFR back in line with the stock sensor.
I posted a series of data logs a while ago here https://forum.ih8mud.com/80-series-tech/347736-obd-ii-data-logs.html
If you look at the unsleeved logs you will see that the AFR is as lows as .63 during idling but the FT% never gets very high with the exception of a non sleeved housing with an attached vacuum line to the FPR.
I wonder if it has something to do with the fuel pump relay being in the low position.
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