E85 - P0171 too lean code - Long Term Fuel Trims + 12.5%
Sep 29, 2014, 09:27 PM
#1
E85 - P0171 too lean code - Long Term Fuel Trims + 12.5%
I recently had a motor built and tuned for both E85/93 octane.
I've been having a few problems with codes lately. First was a P0403 EGR insufficient flow (I know it was and EGR insufficient flow code, I think 403 was the number). It turned out that the small hose that connects to the bottom of the EGR valve blew off (or wasn't connected). I fixed that by zippy-tieing it as tight as possible after I reinstalled the hose.
A week or so later I threw a P0171. I searched for another boost/vacuum leak and found another small hose disconnected below the intake manifold (behind the engine) feeding to the EGR solenoid. I fixed that the same way - zip-tied tight as I could make it.
Car (It's an IX) is set to about 32-33 psi for boost when running on E85. I have 1800cc FIC injectors.
Car has a wide band that is set for lambda value. When cruising and idling lambda is at 1.0, or darn close. Car seems to run good.
When I called my builder/tuner the first thing he asked me was "how many tanks of E85 have you used". I have only filled up with 1 tank of E85 locally and I didn't test it. What he believes is that the ethanol content may be off and this may be causing the lean codes and the rich adjustment. When I talked to him, I didn't realize that it was at 12.5, which I believe is the max rich the PCM will adjust.
My thought and question is, isn't +12.5 for LTFT alot to account for ethanol content variation? I have not done a boost leak test and this is one of my next steps.
I ordered a tactrix cable and I may be adjusting the injectors (with instruction from my tuner) but I keep scratching my head thinking that the 12.5 is just a lot to account for only ethanol variation (say if my E85 was actually e75 or so)
I could always drain the tank and see if the problem exists after filling up with 93 and switching to my 93 tune....
I did test E85 from a local station today (not the one I bought my last tank from) and it was close to E85. (Probably say about E83 or E84) - I could always fill up with this (I have a half tank now) and see if the LTFT's go down right?
I've been having a few problems with codes lately. First was a P0403 EGR insufficient flow (I know it was and EGR insufficient flow code, I think 403 was the number). It turned out that the small hose that connects to the bottom of the EGR valve blew off (or wasn't connected). I fixed that by zippy-tieing it as tight as possible after I reinstalled the hose.
A week or so later I threw a P0171. I searched for another boost/vacuum leak and found another small hose disconnected below the intake manifold (behind the engine) feeding to the EGR solenoid. I fixed that the same way - zip-tied tight as I could make it.
Car (It's an IX) is set to about 32-33 psi for boost when running on E85. I have 1800cc FIC injectors.
Car has a wide band that is set for lambda value. When cruising and idling lambda is at 1.0, or darn close. Car seems to run good.
When I called my builder/tuner the first thing he asked me was "how many tanks of E85 have you used". I have only filled up with 1 tank of E85 locally and I didn't test it. What he believes is that the ethanol content may be off and this may be causing the lean codes and the rich adjustment. When I talked to him, I didn't realize that it was at 12.5, which I believe is the max rich the PCM will adjust.
My thought and question is, isn't +12.5 for LTFT alot to account for ethanol content variation? I have not done a boost leak test and this is one of my next steps.
I ordered a tactrix cable and I may be adjusting the injectors (with instruction from my tuner) but I keep scratching my head thinking that the 12.5 is just a lot to account for only ethanol variation (say if my E85 was actually e75 or so)
I could always drain the tank and see if the problem exists after filling up with 93 and switching to my 93 tune....
I did test E85 from a local station today (not the one I bought my last tank from) and it was close to E85. (Probably say about E83 or E84) - I could always fill up with this (I have a half tank now) and see if the LTFT's go down right?
Last edited by Jp7; Sep 29, 2014 at 09:35 PM.
Oct 12, 2014, 04:44 PM
#7
Update: I boost-leak tested the car today, and filled up with fresh E85. E85 was actually tested at about E83.5 or so (see photo)
Immediately I found ANOTHER small vacuum hose under the intake manifold that had "boosted" itself loose. - corrected with a zip-tie.
I heard a hiss around the intake manifold/fuel injector area and it turns out number 3 fuel injector wasnt installed correctly. The rubber ring seal is bubbling out. I verified by spraying soapy water on it, you can see bubbles form. The other injectors don't have this problem.
My BOV is a Tial QR and it is brand new (the builder installed this as well). When I boost leak tested it I had to disconnect the recirculating hose that runs back to the atmosphere side of the turbo - this is leaking air real bad too. Should I be capping this side of it off when I do the test? I held it with my hand so I could search for other leaks. Even with my hand sealing it I was not getting more than 3 or 4 PSI. I didn't turn up the pressure because I know I have that injector leak and I want to fix that before further boost leak testing.
With the fixed vacuum line I found the long term fuel trim was still at +12.5 on the drive home, so it did not fix the problem. Car starts and idles much better though. Before (when it was stone cold with the vacuum leaks) it would not even idle without stalling.
Immediately I found ANOTHER small vacuum hose under the intake manifold that had "boosted" itself loose. - corrected with a zip-tie.
I heard a hiss around the intake manifold/fuel injector area and it turns out number 3 fuel injector wasnt installed correctly. The rubber ring seal is bubbling out. I verified by spraying soapy water on it, you can see bubbles form. The other injectors don't have this problem.
My BOV is a Tial QR and it is brand new (the builder installed this as well). When I boost leak tested it I had to disconnect the recirculating hose that runs back to the atmosphere side of the turbo - this is leaking air real bad too. Should I be capping this side of it off when I do the test? I held it with my hand so I could search for other leaks. Even with my hand sealing it I was not getting more than 3 or 4 PSI. I didn't turn up the pressure because I know I have that injector leak and I want to fix that before further boost leak testing.
With the fixed vacuum line I found the long term fuel trim was still at +12.5 on the drive home, so it did not fix the problem. Car starts and idles much better though. Before (when it was stone cold with the vacuum leaks) it would not even idle without stalling.
Last edited by Jp7; Oct 12, 2014 at 04:53 PM.
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Oct 13, 2014, 06:54 PM
#8
I think you have three options: (a) change your tuner, (b) learn how to do it yourself, (c) take it back to your tuner and ask him to finish the job properly.
The reason your LTFT is positive is probably because the tune is not right. If you had less than E85 this would make it run rich, driving the trims negative. If you had a boost leak this would make it run rich under mild boost driving trims negative and slighlty lean in decel or idle. The fact that they are positive and maxed out means that your injectors are possibly not scaled correctly. This probably means that your tuner has not done a very good job, and you should consider taking your business somewhere else.
If you want a full diagnosis you are going to have to post up your ROM and logs showing RPM, Load 1 byte, STFT, LTFT Low, LTFT mid, WBO2 AFR, Boost, Air Flow Hz and IPW during idle and cruise. Without this detail you can't expect an answer of any value.
The reason your LTFT is positive is probably because the tune is not right. If you had less than E85 this would make it run rich, driving the trims negative. If you had a boost leak this would make it run rich under mild boost driving trims negative and slighlty lean in decel or idle. The fact that they are positive and maxed out means that your injectors are possibly not scaled correctly. This probably means that your tuner has not done a very good job, and you should consider taking your business somewhere else.
If you want a full diagnosis you are going to have to post up your ROM and logs showing RPM, Load 1 byte, STFT, LTFT Low, LTFT mid, WBO2 AFR, Boost, Air Flow Hz and IPW during idle and cruise. Without this detail you can't expect an answer of any value.
Oct 4, 2015, 10:42 PM
#10
Update:
Car was down from November until September. I've been working on some other things. I have since rebuilt the fuel rail with a slightly different setup and I removed and replaced the injectors. Car has not been driven on E85 yet but it runs great on 93. I believe the problem may have been from a vacuum leak on that number 3 fuel injector seal. After I reinstalled the injectors carefully with P80 lubricant on the seals that appear to be sealing right. Last november I tried to boost leak test this and I had all kinds of air coming out of this seal. I have not really boosted hard but it idles great now with the 93. I may not have the time to switch back to E85 and test this before the car goes away from winter but I am code-free now.
Car was down from November until September. I've been working on some other things. I have since rebuilt the fuel rail with a slightly different setup and I removed and replaced the injectors. Car has not been driven on E85 yet but it runs great on 93. I believe the problem may have been from a vacuum leak on that number 3 fuel injector seal. After I reinstalled the injectors carefully with P80 lubricant on the seals that appear to be sealing right. Last november I tried to boost leak test this and I had all kinds of air coming out of this seal. I have not really boosted hard but it idles great now with the 93. I may not have the time to switch back to E85 and test this before the car goes away from winter but I am code-free now.
Last edited by Jp7; Oct 4, 2015 at 10:44 PM.
Oct 6, 2015, 12:09 PM
#11
Update:
Car was down from November until September. I've been working on some other things. I have since rebuilt the fuel rail with a slightly different setup and I removed and replaced the injectors. Car has not been driven on E85 yet but it runs great on 93. I believe the problem may have been from a vacuum leak on that number 3 fuel injector seal. After I reinstalled the injectors carefully with P80 lubricant on the seals that appear to be sealing right. Last november I tried to boost leak test this and I had all kinds of air coming out of this seal. I have not really boosted hard but it idles great now with the 93. I may not have the time to switch back to E85 and test this before the car goes away from winter but I am code-free now.
Car was down from November until September. I've been working on some other things. I have since rebuilt the fuel rail with a slightly different setup and I removed and replaced the injectors. Car has not been driven on E85 yet but it runs great on 93. I believe the problem may have been from a vacuum leak on that number 3 fuel injector seal. After I reinstalled the injectors carefully with P80 lubricant on the seals that appear to be sealing right. Last november I tried to boost leak test this and I had all kinds of air coming out of this seal. I have not really boosted hard but it idles great now with the 93. I may not have the time to switch back to E85 and test this before the car goes away from winter but I am code-free now.
Oct 6, 2015, 02:04 PM
#12
Same injectors were installed again but I put the seals in correctly. It was difficult. I have the blue FIC seals. They are REALLY tight in there. Viton? I think?
I had to install the seals into the intake manifold first. I then installed the injectors into my buschur fuel rail (I lubricated everything with P80 assembly lubricant for fuel system parts). I slowly torqued the rail down and drew it into the seals. I took my time and it looks pretty good now. (way better than before when the bottom was all bubbled out.)
Oct 6, 2015, 02:29 PM
#13
Injectors were sitting on my mechanics cart for a few months while I built my zietronics flexfuel plumbing setup. They looked good to me, I couldn't see anything obvious.
Same injectors were installed again but I put the seals in correctly. It was difficult. I have the blue FIC seals. They are REALLY tight in there. Viton? I think?
I had to install the seals into the intake manifold first. I then installed the injectors into my buschur fuel rail (I lubricated everything with P80 assembly lubricant for fuel system parts). I slowly torqued the rail down and drew it into the seals. I took my time and it looks pretty good now. (way better than before when the bottom was all bubbled out.)
Same injectors were installed again but I put the seals in correctly. It was difficult. I have the blue FIC seals. They are REALLY tight in there. Viton? I think?
I had to install the seals into the intake manifold first. I then installed the injectors into my buschur fuel rail (I lubricated everything with P80 assembly lubricant for fuel system parts). I slowly torqued the rail down and drew it into the seals. I took my time and it looks pretty good now. (way better than before when the bottom was all bubbled out.)
New injector seals at the intake manifold are not easy to seat properly. They definitely need a bit of lube and good alignment to go in correctly.
Aug 15, 2017, 08:56 PM
#14
ok, because one cause of a lean condition are injectors getting badly clogged. When running E85, sometimes a thick, black sludge/gunk can build up on the injector tips that can cause this. Its quite obvious.
New injector seals at the intake manifold are not easy to seat properly. They definitely need a bit of lube and good alignment to go in correctly.
New injector seals at the intake manifold are not easy to seat properly. They definitely need a bit of lube and good alignment to go in correctly.
This may or may not be related to E85 contamination. I did find one of the little hoses that is underneath the intake manifold was blown off of a "T" fitting junction. I fixed that and started the car. Long term went down from 12.5 to about 10.9. Not as much as I expected. I have not driven the car though. This was just in the garage idling to warm it up.
I did drive this car from July 4th till now more than usual. I put about 170 miles on the tank of E85. My tank is just about empty now. I do have an ethanol content sensor and the content varies between 79% and 83% so my ethanol content is good. I am wondering if I have buildup on my injectors contributing to this problem. My fuel pressure at rest with the factory regulator is about 38 psi. Keep in mind I have a fuel pressuge gauge on my fuel rail. This is being affected because I do have the vacuum line connected to the regulator. This is the same fuel pressure I have always seen before this code popped up yesterday.
I bought a smoke test machine today so I'm excited to get that soon. I want to check for boost/vacuum leaks. More to come.
I was going throw some sea-form in the tank and see if that would help the injectors (assuming those are part of the problem).
My tank is literally empty now anyways.
