E85 - P0171 too lean code - Long Term Fuel Trims + 12.5%
Aug 16, 2017, 12:18 AM
#16
The most that the E85 has been in the tank has been probably 2 months (at one time). I start the car and run it until the fans turn on atleast every other week.
Aug 16, 2017, 06:32 AM
#17
Be careful about getting into boost with the very lean fuel trims. Depending on how the car was tuned, the best case scenario situation is that the ECU can somewhat correct for the lean condition up to about maybe 15-20 psi, but after that, the correction is not applied. Worst case is that no correction is applied after about 2-3 psi of boost.
There are definitely several possible reasons why this could be happening. As I said, it could be injector gunk. It could also be that the car was tuned for E85 on E50. That would produce a lean condition if you are now running E79-83. It could also be a crappy tune. First step is always to eliminate possible mechanical issues, so if it were my Evo, I would pull the injectors to inspect. At a minimum, it provides useful information about whether gunk buildup is an issue in your area.
There are definitely several possible reasons why this could be happening. As I said, it could be injector gunk. It could also be that the car was tuned for E85 on E50. That would produce a lean condition if you are now running E79-83. It could also be a crappy tune. First step is always to eliminate possible mechanical issues, so if it were my Evo, I would pull the injectors to inspect. At a minimum, it provides useful information about whether gunk buildup is an issue in your area.
Aug 16, 2017, 10:23 AM
#18
Be careful about getting into boost with the very lean fuel trims. Depending on how the car was tuned, the best case scenario situation is that the ECU can somewhat correct for the lean condition up to about maybe 15-20 psi, but after that, the correction is not applied. Worst case is that no correction is applied after about 2-3 psi of boost.
There are definitely several possible reasons why this could be happening. As I said, it could be injector gunk. It could also be that the car was tuned for E85 on E50. That would produce a lean condition if you are now running E79-83. It could also be a crappy tune. First step is always to eliminate possible mechanical issues, so if it were my Evo, I would pull the injectors to inspect. At a minimum, it provides useful information about whether gunk buildup is an issue in your area.
There are definitely several possible reasons why this could be happening. As I said, it could be injector gunk. It could also be that the car was tuned for E85 on E50. That would produce a lean condition if you are now running E79-83. It could also be a crappy tune. First step is always to eliminate possible mechanical issues, so if it were my Evo, I would pull the injectors to inspect. At a minimum, it provides useful information about whether gunk buildup is an issue in your area.
Before when i had this same lean code I didn't see any buildup on the injectors. Is this on the intake manifold side, or in the fuel rail side? I did find a rolled o-ring before and I thought that it was my root cause.
Here are my pictures from 2014/2015. They were on photobucket before the max exodus.
Last edited by Jp7; Aug 16, 2017 at 10:33 AM.
Aug 16, 2017, 12:16 PM
#19
Evolved Member
it may just need a injector rescale.
If you've eliminated all other possibilities like fuel quality and vaccum leaks.
I would Add 12 % to your injector latency values.
If you've eliminated all other possibilities like fuel quality and vaccum leaks.
I would Add 12 % to your injector latency values.
Aug 16, 2017, 12:24 PM
#20
I know on some cars you actually have to drive the car after you've fixed a vacuum leak or the CEL won't go away. Sometimes it takes a while for the long term trims to go back towards zero.
I get my smoke machine tomorrow so I plan on taking off my air-filter and building an adapter so I can smoke test the intake. This will be a weekend project. I am excited I've always wanted a smoke machine.
Last edited by Jp7; Aug 16, 2017 at 12:34 PM.
Aug 16, 2017, 02:38 PM
#21
The buildup occurs on the injector tips where fuel sprays out, so they have to be removed to see the buildup.
Definitely fix the rolled orings. They can contribute to the lean condition.
So you can kill two birds with one stone - replace rolled orings and check for gunk.
Who installed those injectors?
Definitely fix the rolled orings. They can contribute to the lean condition.
So you can kill two birds with one stone - replace rolled orings and check for gunk.
Who installed those injectors?
Aug 16, 2017, 06:40 PM
#22
Evolved Member
I did find a vacuum leak yesterday where the little hoses on top of the intake manifold go south down the back of the engine. One of the hoses on the "T" came loose so I zip tied it back together. The boost must have been pushing them off.
I know on some cars you actually have to drive the car after you've fixed a vacuum leak or the CEL won't go away. Sometimes it takes a while for the long term trims to go back towards zero.
I get my smoke machine tomorrow so I plan on taking off my air-filter and building an adapter so I can smoke test the intake. This will be a weekend project. I am excited I've always wanted a smoke machine.
I know on some cars you actually have to drive the car after you've fixed a vacuum leak or the CEL won't go away. Sometimes it takes a while for the long term trims to go back towards zero.
I get my smoke machine tomorrow so I plan on taking off my air-filter and building an adapter so I can smoke test the intake. This will be a weekend project. I am excited I've always wanted a smoke machine.
Fix all leaks. Clear code. Remove battery cables and press horn or high beams to suck all the juice out the system. Reconnect. Let idle for 28 minutes see were your low trims set. Then go cruise for 30 min steady throttle as can be and see were your mid sets. It takes quite a while for trims to set.
Aug 16, 2017, 06:42 PM
#23
Here is my current setup after the o-ring repair:https://www.evolutionm.net/forums/e8...or-hose-3.html
My boroscope is really awesome, I should have no problems at all getting it through the throttle body if I open my throttle butterfly and take off my cold side intercooler pipe.
Last edited by Jp7; Aug 16, 2017 at 06:48 PM.
Aug 16, 2017, 09:30 PM
#24
I missed that you already fixed the o-rings. Since that issue is fixed, its likely that its one or both of the two issues that I mentioned before - The E85 tune is not good, and/or the injectors are badly gunked up. If the borescope is that versatile, go for it, although I think it might be easier to pull the injectors than it would be to remove the throttle body and then try to get a good view of the injector tips with the borescope.
Aug 16, 2017, 09:52 PM
#26
would it be too simplified to say that the injector pulsewidth should be a ratio (greater than 1, probably closer to 1.3 or 1.4) times the 93 octane tune, if the goal is to run at stoich?
Obviously when it gets to the higher load portion of the map the mixture will change but since my code is being thrown on the low load side (25% load) I would guess (in my ignorance) that we can ignore that for now.
I do have my tune on a flash drive with me, I can upload it if that helps.
Last edited by Jp7; Aug 16, 2017 at 10:01 PM.
Aug 20, 2017, 01:47 PM
#28
They are 1800cc FIC injectors.
Update- I got my smoke machine yesterday and I tested the system for leaks. I pulled off my maf housing and adapted a 3" pipe plug for PVC and it fit perfect. I drilled a hole in the plug and put in some smoke from the smoke tester. Immediately it started leaking from the pipe that feeds the turbo intake side, there was a reasonable sized leak where the recirculating valve dumps back into the intake side of the compressor as well. I would imagine that unmetered air was sneaking in here. Not a vacuum leak, but it is still air that is not being accounted for by the MAF. I fixed these leaks and retested with the smoke machine, they were good. I am currently waiting to put everything back together because I need a 60 degree 3 inch silicone coupler. I am not happy with the angle of the one I've had on there.
I'll tell you guys this- as far as trouble shooting goes, having a smoke tester is amazing. I wish I bought one of these years ago. Only problem is my shop smells like a barbeque lol.
I let it run for a while, pushing smoke. The MBC barely, barely just barely leaks - but an MBC is supposed to leak (it's a controlled, small leak - right?)
Aug 20, 2017, 08:14 PM
#30
