I've got a GEN 1 on a supercharged engine. The vehicle is new to me. Should I make the switch to the GEN 3 when available?
P0171 with Landtank's MAF
- Thread starter NLXTACY
- Start date
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is it sleeved?
Negative.
Right now I'm investigating on making more sleeves. But the count needs to be rather large to get the price down. There is a thread in the vendor section that you should watch for updates.
Got it. Thanks for the information.
Just bumping this as I just finished a 3000 mile trip running the Gen 1 housing. I would consistently get a P0170 code every day after a few starts. The LTFT seems to settle fairly quickly to +19.53 at idle. After consecutive starts that would go into the +20's until it would trip the CEL P0170 code.
I did a lot of interstate cruising and under those conditions with the engine stuck around 2200-2400 PRMs it would have STFT numbers floating between -5 and +5 and the LTFT would be somewhere around +5.
Anytime I'd come off throttle quickly the STFT and LTFT would go very positive immediately. Most of this was very predictable and didn't seem to affect anything. I'd reset the CEL and the LTFT would pop back down to +19.53 at idle and then once I'd be at highway speeds it would be +5 or so.
The only time it was annoying was when I was on a trail in low range going slowly. Then the LTFT would be in the high +20's, sometimes into the low 30's and would trip a CEL often.
So is this hurting the engine to run it like this? I had the truck pretty loaded with a Yakima hard case on top and running 315 tires and averaged 14 mpg for the whole trip which I thought was pretty good given that the bulk of the trip was spent driving 70-75 mph.
I'll admit it is a little annoying to try and read through the various threads dealing with this MAF housing to determine what the best solution is.
I did a lot of interstate cruising and under those conditions with the engine stuck around 2200-2400 PRMs it would have STFT numbers floating between -5 and +5 and the LTFT would be somewhere around +5.
Anytime I'd come off throttle quickly the STFT and LTFT would go very positive immediately. Most of this was very predictable and didn't seem to affect anything. I'd reset the CEL and the LTFT would pop back down to +19.53 at idle and then once I'd be at highway speeds it would be +5 or so.
The only time it was annoying was when I was on a trail in low range going slowly. Then the LTFT would be in the high +20's, sometimes into the low 30's and would trip a CEL often.
So is this hurting the engine to run it like this? I had the truck pretty loaded with a Yakima hard case on top and running 315 tires and averaged 14 mpg for the whole trip which I thought was pretty good given that the bulk of the trip was spent driving 70-75 mph.
I'll admit it is a little annoying to try and read through the various threads dealing with this MAF housing to determine what the best solution is.
sleeoffroad
Supporting Vendor
Rick, can you explain what you mean with this? Or reference where you got the info on this?
A LTFT that is off at idle still shows that there is something wrong. Why would it trip a code at idle with LTFT being off if it did not matter.
What is the upper limit of LTFT correction? I know my other car it is 34% after that the car can't adjust fuel demands past the needs of the car. If the 80 is similar running it in the 20's doesn't leave much room before it can no longer meet the fueling needs. Just as another data point I was high 18's at idle with the GEN I, before I removed it.
What tool can I use to calculate LTFT and STFT? I ran into this link that gave me sort of an idea but I'm guessing things might be a bit different for 1FZJ engine.
http://stealth316.com/misc/obdii_fuel_trim.pdf
http://stealth316.com/misc/obdii_fuel_trim.pdf
A good scan tool will read the fuel trims, which are calculated by the engine ECM. You will need a scanner that will read live data
I tried my best to get the P0171 to trigger at idle and couldn't make it happen. It was after the second trip that it finally trigger. Just my experience with the system.
And these tests were done with a GENI housing with the vacuum line still attached. Not the way it was intended to be installed but a worse case scenario for evaluating the housing and provided MAF sensor. I wanted to be sure to trigger a P0171 and wanted to FT% to be as high as possible to show how the ECU deals with this sort of error and maintains proper AFRs.
The high FT% in this case was expected.
Everyone running a GENI in this manner can expect this condition. I have posted this a lot in an attempt to let people know about it.
I have offered a path for those who have the GENIs to correct the high FT% at idle but people have either decided against it or just not realized it was available. And some will also install it incorrectly with the vacuum line attached. That very well could be unintentional as the stock MAF requires it as well as the housing made after the GENIs.
Toyota triggers a P0171 at 20%. I had my truck at 52+% and it was still maintaining the proper AFR.
As for your data point, was the vacuum line still connected? And why did you bother running an outdated design when you had a GENIII in hand?
Your engine is running fine and you likely still have the vacuum line attached to your FPR.
No need to read through these threads, just drop me a line.
I'm having more sleeves made for those who didn't get a sleeve the last time. These sleeves will correct the FT% you have now, allow the vacuum line to stay on the FPR and not have the timing issue of the GENIIs
There is a thread in the vendor section with all the info needed to help identify which housing you have and the protocol for correcting it.
I just read this entire thread- as painful as it was. I just bought an 97 80 with 147k miles and knew when I bought it had thrown code P0171. It was found at inspection and had an exhaust leak that was fixed before delivery. I was hoping that would be the fix. When I fix got in it and stepped on the gas it was a bit sluggish. When I first got out of it and walked around while idling I did smell fuel. Today, after I had it going pretty good above 55 mph I left off the gas and BINGO the light comes on.
However, with all the discussion I have yet to see a comprehensive list in order to attack the problem. There was some rabbit chasing on the thread, but I think this is the order to go to get this CEL P0171 gone. The ones in bold or red seem to be the main fixes. @sleeoffroad How is this?
1. Check for air leaks in air intake
2. Change Air Filter
3. Clean MAF Sensor and Intake Manifold
4. Check MAF connections
5. Change Fuel Filter
6. Check or replace all vacuum lines
7. Check O2 Sensors or maybe bad catalytic converters?
8. Knock Sensor
9. Crank Position Sensor
10. ECU
However, with all the discussion I have yet to see a comprehensive list in order to attack the problem. There was some rabbit chasing on the thread, but I think this is the order to go to get this CEL P0171 gone. The ones in bold or red seem to be the main fixes. @sleeoffroad How is this?
1. Check for air leaks in air intake
2. Change Air Filter
3. Clean MAF Sensor and Intake Manifold
4. Check MAF connections
5. Change Fuel Filter
6. Check or replace all vacuum lines
7. Check O2 Sensors or maybe bad catalytic converters?
8. Knock Sensor
9. Crank Position Sensor
10. ECU
TrickyT
Hate that mud...
I'm not sure how #8, 9, and 10 got associated with P0171 in this thread, but they are not listed as possible causes in the FSM and should be removed from your list. On the other hand, the FSM does list the engine coolant temperature sensor as a possibility.
And just to be clear, since you don't specifically mention it in your post, this whole thread was started for those here who have replaced their factory MAF with one sold by @landtank. There are multiple generations of the Landtank MAF and it could be that one was more sensitive to this code than others.
EDIT: And the root cause of the problem the OP posted about was a bad MAF sensor bought used from eBay.
And just to be clear, since you don't specifically mention it in your post, this whole thread was started for those here who have replaced their factory MAF with one sold by @landtank. There are multiple generations of the Landtank MAF and it could be that one was more sensitive to this code than others.
EDIT: And the root cause of the problem the OP posted about was a bad MAF sensor bought used from eBay.
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Interestingly enough, my codes were solved by the complete replacement of the exhaust and two new Denso O2 sensors. Not the cheapest way to go but it needed to be done. I went with the magnaflow y pipe and muffler and the borla cat back. All went together well (paid exhaust shop).
Sent from my iPad using IH8MUD Forum
Sent from my iPad using IH8MUD Forum
I know this is old but I have the Landtank MAF and was throwing PO171 every 30 miles or so. TorFab took a look and they didn't think it was anything to worry about but it still drove me insane. Reading all this issue that would cause this code I started replacing the easy stuff first.
1. Intake(I believe I cracked this while checking it for cracks) hose, CEL came back PO171
2. Front O2 sensor(the front O2 sensor looked axtremely old and the bolts were rusted) CEL came back
3. Fuel pump relay($30 on ebay for an OEM part), CEL came back PO171
4. Fuel pump, sock also changed the air filter NO CEL.
Just took it on a trip into the mountains 180 miles No CEL Hope this helps.
1. Intake(I believe I cracked this while checking it for cracks) hose, CEL came back PO171
2. Front O2 sensor(the front O2 sensor looked axtremely old and the bolts were rusted) CEL came back
3. Fuel pump relay($30 on ebay for an OEM part), CEL came back PO171
4. Fuel pump, sock also changed the air filter NO CEL.
Just took it on a trip into the mountains 180 miles No CEL Hope this helps.
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Did you clean the MAF sensor?
Probably should have mentioned that, cleaning the MAF was the first thing i did before replacing any parts
