High long term fuel trim at idle. Clean or replace a faulty mass air flow sensor. With a code reader that can read live data reviled long term fuel trim at +29% and +26% on the two banks, and short term fuel trim to be with in a few percent of zero at idle. Long fuel trim responds when short fuel trim drifts too far Aug 4, 2022 · Negative Fuel Trim ( Long- and Short-term) Months ago, I cleaned the MAF sensor and throttle body (did not remove from the engine) and manually performed the throttle position sensor reset and idle relearn (with no telling if I did it correctly). Hooked up my obdii tool and noticed my bank one long turm fuel trim was at -10. 5% to 10%. Always verify the STFT (short-term fuel trim) and the LTFT (long-term fuel trim) while reading live data from your Innova OBDII scan tool. This data is telling the technician the problem is fixed. Fuel Pressure steady but low at 43psi. 5L - 190k. Background: This all started when this new-to-me GTO failed our Colorado Dynamic emissions test with High average NOx and HC numbers which to me seemed to come from huge spikes when the operator changed the throttle position. Scanning the engine computer for DTCs found a P0300 (Random Misfire) stored in memory. Your high LTFT in conjunction with the smell may be due to the engine actually running rich because the AF feedback is erroneously showing a lean condition. The long term fuel trim will use the fuel trim table to determine how to control the short term. Now that would of course be a classic sign of a vacuum leak. If any are > 8% then you likely have a vacuum leak. However at 1500 rpm long term fuel trim are +7 and short term varies between - 7 to -23. unmetered air (intake snorkel leak, other loose fitting vacuum hosesgoogle cigar smoke test for more info) Feb 5, 2022 · Short-Term Fuel Trim (STFT) STFT is a measure of the fuel trim value over a short period, typically a few seconds. 4L L4, for example, this DTC is set if the average long term fuel trim weighted average value is greater or less than a calibrated value. Bank 2 does have the higher fuel trim too by the way (by about 1-3%) 2005 Avalon Limited, 3. Long-term fuel trim in the normal range will be a topic for another day. Nov 16, 2020 · Dear Experts here im attaching log of 1SZ-FE, 1. Installed new air fuel ratio sensor and test drove. Meaning that the RPMs are not fluctuating, and its steady. using 93 octane pump gas _____ Just wondering if this is ok per HP Tuners, during idle with the engine at normal Apr 30, 2014 · Especially a long duration high lift cam. 1%. The list of usual suspects that cause negative fuel trims is short; over-reporting MAF, high fuel pressure, leaking injector (s), sticking purge valve, excessive EGR. So, there is too much fuel in the blend. CAR: Completely stock, I think, except for a CatBack and K&N Intake. Jul 5, 2021 · After restart the Long Term Fuel Trims went nice and low, down below 5% at idle. 5% confirmed this. 8%. When you get a custom tune, your tuner will do what’s called a MAF Feb 22, 2023 · A long-term fuel trimmer upper at idle is one common issue that can affect the performance of your car engine. 64) Understanding these terms and their relationship will help you understand how to use fuel trim data shown on a scan tool. when the truck is under load close to flooring it 96% load the long term fuel trim drops to around bank 1 9. Engine is reasonably well maintained, air filter and plugs, oil changed on schedule. Other possible causes of negative LTFT include a leaking intake manifold gasket, vacuum leak, dirty or clogged air Aug 25, 2016 · High fuel trim finally fixed. It will throw a Random miss fire code or a miss fire core on cylinders 4 and 6 but this can be Dec 2, 2023 · Resolved and resmoked, problems solved. 3. 7:1 for example) or as a Lambda value. Your rear O2 feedback showing the cat function as irregular Apr 25, 2022 · C6 Scan & Tune - High long term fuel trims at idle > - 2011 Corvette LS3 with supercharger and a fairly mild aftermarket cam (220°/234° . -9° Overlap) . New belts (timing and serpentines) 12. See more. Jul 21, 2021 · I replaced my injectors a few years back after identifying them as the problem behind lean idle codes with long term fuel trim (LTFT) readings 32+ for both banks. 9 (adding) while driving it varies from 5 to 10 adding. 3 WT 4x4 Crew short box. 198,000 miles. Long-term banks 1 and 2 are 1. On idle, ST and LT seem okay (around 0% - 2%). short term fuel trims seem to hover around 0 like it should all the time. I estimate the lambda to be about 1. wirelessf Discussion starter. Dec 31, 2021 · My Short term is consistently around 0 throughout all RPMS. I've been trying to diagnose a fuel trim issue for some time now. But, you can watch the sensor share the negative trim numbers. not high enough to trip a cel for lean running but still above 10% threshold. Dec 17, 2021 · Of all your numbers in post #6, the long and short term fuel trims are the most out of whack. 7 parts air to 1 part fuel. I've had 19. The STFT returns to zero after the engine May 12, 2022 · AVC. The customer complaint is rough idle and poor power. Mar 22, 2021 · short term fuel trim is shows -3 to +3 and zero often . Elevate engine RPM to around 2000 to 25o0 RPM in park and record the fuel trim numbers. This is known as "Stoichiometric", a Nov 30, 2023 · To fix negative long-term fuel trim, you may need to: Replace a leaking fuel injector. Analyze the collected data. Long-Term Fuel Trim (LTFT) Jan 19, 2020 · 2013 5. With a hot engine at idle, check the 4 fuel trims, 2 short-term and 2 long-term. 8% at idle. Feb 11, 2015 · The formula for fuel trim calculation is: Fuel mass = Air mass x (short-term fuel trim x long-term fuel trim) divided by (equivalence ratio x 14. Oct 16, 2015 · The long-term fuel trim (LTFT) is a stored value which accounts for changes in engine condition, wear and tear, etc. Absolute TPS reads 19. Sep 11, 2007 · Once the O2 sensors warm up, the ECM switches to closed-loop (CL) mode and begins using them to adjust the short-term fuel trim (STFT) to maintain the ideal 14. Apr 22, 2015 · This will get you to your desired trim much quicker than trims which have been in place for a while. There is consistently a small difference in LTFT between the banks. 6, and the short term trims are near zero. Long-Term Fuel Trim (LTFT) Aug 8, 2019 · The STFT varies between -4 and +6. Dec 9, 2011 · Hi guys, just after a bit of advice on my foz. Mar 2, 2009 · All emission tests completed ok, but every now and then, p0173 would appear. The rich mixture means that there is more fuel than needed and the air/fuel ratio is too rich. What is short-term fuel trim (STFT)? Short-term fuel trim is the short-lived and immediate response of the ECM to the changes in the exhaust gasses. Jan 1, 2020 · Short Term Fuel Trim (STFT) is representative of the current adjustments the ECM is making to injector pulse width (fuel control) and Long Term Fuel Trim (LTFT) is a learned correction over a period of time. May 22, 2017 · Operate the vehicle at idle in park and record the fuel trim numbers. The LTFT B1 range refers to the percentage of fuel trim over a long period of time for cylinder bank 1. With iso-octane ("ideal" gasoline), Lambda of 1. 2. 4. The negative number shows you how much fuel the injectors are not sending into the mix. My engine may of overheated and I'm pretty sure some water got in. Short term fuel trims are centered around zero, typically within +/-5%, with the rare spike to something more (negative 10 The sensor will not diagnose if the negative long-term fuel trim is high. (-18) LTFT at idle only then within range. 5% LTFT 2 + 10% STFT on both banks staying +/-5% all RPMs/loads. However, FSM states +/-20% is ok. Initial diagnosis may display any of these misfire and/or fuel trim related codes: Aug 8, 2019 · The STFT varies between -4 and +6. This is on a 2009 Honda CR-V. Pos= lean) When doing a road test bank 1 and 2 equaled out at -2. Suspecting filter/fuel pressure regulator/fuel pump. A high positive long term fuel trim suggests that the ECU thinks that the car is running lean, so it's adding more fuel to compensate. Find out the possible causes of a high LTFT and how to diagnose and fix them. Apr 1, 2012 · 19. 0 is equal to 14. Feb 12, 2011 · The PCM looks at LTFT + STFT and if the total is ~30% or more it will set the P0171/P0174 code for Bank 1 and/or 2. O2 sensor faulty. my Long term fuel trims are high, long term fuel trim often at idle it's at 10. Changed and cleared check engine lights. As the engine warms up, the ECM slowly reduces RPM and the STFT slowly Feb 14, 2008 · 01 Toyota Tundra 2UZ-FE V8 . Jun 5, 2019 · At Idle, short term fuel trim bank 1 is about 10-18%. Freeze frame data shows LTFT1 +19. 8V. Bank 2 was at -2. Trying out a new tuner. If the condition exists in all rpm ranges, the cause is more likely a fuel supply issue caused by low fuel pressure, a restricted injector or a defective sensor input Jul 21, 2018 · Learn what long term fuel trim is and how it affects your engine performance and emissions. Jan 26, 2021 · Long-term fuel trim relies on sensors further downstream in the exhaust system, past the catalytic converter. If the negative trim goes past -10, then it is excessively high. Jun 1, 2021 · Hello, I just checked yesterday my car ( Daihatsu Sirion 2006 1000cc ) with the OBDII tool and found the Long term fuel trim to be -15% when parked idling ( Tested after driving ). D rive the vehicle and make a scan tool recording to calculate volumetric efficiency, and record fuel trim numbers while the engine is under some load. Feb 5, 2022 · Short-Term Fuel Trim (STFT) STFT is a measure of the fuel trim value over a short period, typically a few seconds. Slightly hard to start and diesels a bit at shut off. it's all consistent. 2 (idle) 13. The short fuel trim was dropping 7 below and rising 7 high above 0. The only way to diagnose this is to take a closer look at your O2 sensors and your short-term fuel trims. Code P0172 may appear on some Chevy vehicles. LTFT is the sum of what the vehicle’s computer system has been doing to ensure the balance of the air-fuel mixture within a particular period. Datalogging indicates high Long Term Fuel Trim (LTFT) @ +15%. Oct 10, 2017 · Did you reset the fuel trims after replacing the fuel pump? Maybe the system is still using the old long-term fuel trim values, which would explain why they are negative (since they were previously positive). I would definitely try resetting the fuel trims and see what that does for you before going much further. I do remember both short and long term fuel trim being at exactly 0% a few days ago. 7:1 air/fuel ratio. Expect a value of five percent positive. P0171 - very gradual fuel trim increase at idle. They Are: Mode/PID: 22163E Long Name: _Fuel Trim Bias Bank 1 Rear O2 Short Nm: REARFT1 Min/Max 0/100 Unit: % Equation: Signed(A)*256+B Header: Auto Feb 11, 2020 · I put the old one in and had a MAF reading 1 most of the time sometimes reaching 2 at idle. When I got my lean code my long term was at 29. The long fuel trim idled at 15. Yes they are somewhat of an average of the short term fuel trims but it is more of a strategy. This is the desired air/fuel ratio, a command issued by Oct 12, 2020 · High Long Term Fuel Trim on Load. -7% or so. Uses 1 quart oil/3,500 miles. Monitor and record the fuel trim values in. O2 sensor bank 2: is steady on 0. 6% and bank two is 17. The post-cat o2 sensor switches with a lot less of a voltage difference than the pre-cat. the four common operating ranges—idle speed, light load (20 to 30 mph), moderate load (40 to 50 mph) and heavy load (60 to 70 mph). Short turm fuel trim bounces back and forth from May 9, 2021 · Your load % is way too high for idle conditions (and why you are pumping too much gas into it). The STFT pre-cat drops to about 1% at engine warmup. I've tried my best to find one (checked everything I could multiple times from using visual Nov 27, 2018 · ALSO: There are two PIDs designated 'REAR FUEL TRIM BIAS' readings. Dec 2, 2017 · 6 years 6 months ago #15453. A/F is expressed as either a ratio (14. Another possible explanation for why your long-term fuel trims stay at 0 is that your O2 Sensor or Sensors are faulty. May 30, 2014 · Fuel trim at 2,500 rpm with new belt. The three most likely candidates are the mass airflow sensor (MAF), oxygen sensor (O2), or upstream air/fuel ratio sensor (A/F). 65 which looks lean. Was this Mar 12, 2016 · Hoping someone with a 2014 2. Fuel regulator show 55 PSI at idle with vacuum line off. Apr 20, 2024 · Fuel trims are the changes that the PCM makes to ensure the air and fuel mixture stays as close to its ideal ratio as possible. After coming to a stop bank 1 went back to -10. There are YouTube video for checking most of those things. Equivalence ratio. When actually driving, and the engine is under a load, LT jumps to 15% . 14% is a bit high. Several things, including a faulty oxygen sensor, a vacuum leak, and a leak in the MAF and intake, can cause this issue. Throttle body is clean. Occasional code P0171, lean bank one. 2L e But here’s the thing: fuel trimming comes in short-term and long-term trims. 4. Tuner hesitates makin Apr 24, 2015 · Checked live data with scan tool while driving and saw that the short term fuel trim dive to -24% at idle along with the long term going negative. Jun 1, 2010 · Longterm fuel trim: 14% (starts around 8% and slowly gets up to 14% when engine gets hotter and with a press of the accelerator pedal. Since then the CR-V started to show some performance issues: Long Term B1 10. Under normal operation, we expect these values to be within 10 percent of zero. ) Oct 17, 2011 · Original sensor typically shows some positive long term trim values. May 19, 2023 · Long-Term Fuel Trim Negative (LTFT) relates to problems with the fuel and air mixture entering the engine during combustion. However, the value can fluctuate since vehicles don’t move at a constant speed. 75, which is far far too high. Hey guys, I have a 99 GMC Sierra with the 5. Like. If you have the big honking cam, you could be getting revision that is causing the split blm. -7% seems within specs, but on the other hand it's not insignificant a number. Have you checked your fuel injectors for proper spray pattern as a clogged injector or 2 on one side can mess with fuel trim. Short-term fuel trims refer to the immediate adjustments made by the PCM to the fuel delivery system based on immediate input from the upstream O2 sensors. Short term trim values are about eh same but sometimes go negative. Front O2 sensors readings appear slightly negative (-2) and the long term fuel trims appear to be at zero. The overall efficiency of your vehicle is also at A long-term fuel trim high at idle is a common question that can impact the performance of your car engine. I wish I could see long term fuel trims but I can not with the torque app. Didn’t see any. AFR 13. Using my scanner, I see that the long term fuel trim is between 14-22 at idle. Inspect and repair the EGR system. Using an OBD II scan tool, high positive long term fuel trims caught my attention: ~10% for Bank 1 and ~13% for Bank 2. . In addition to these no-load checks, drive the vehicle at various steady load conditions and watch for fuel trim variation. Nov 7, 2023 · Reason 3: O2 Sensor is Faulty. On a 2016 Chevrolet Equinox L 2. This will allow all of the residual juice in the PCM to bleed off and cause it to lose its saved memory. Now it reads 13-17% LTFT (long term fuel trim) I zip-tied all vacuum hoses going to the intake manifold May 8, 2006 · Here is an explanation of fuel trim and what it does for us. 7V at idle. 3 volts, kinda fluctuates between that pretty often at both idle & 3,000 RPMs. 2 Ecotec engine, not DI, no turbo. But from monitoring them, I can tell they have some weight on direction of Fuel Trims. Loaded 5020 map, and am seeing short FT at around 10 at idle and 25-30 at cruise. Long Term Fuel Trim (LTFT) is the adaptive strategy side of the system and those values will be used for baseline purposes in this analysis. 9%. Nov 10, 2022 · Links Below: High Positive Long Term Fuel Trim. IDK what their meaning is specifically. No carbon deposits on plugs. 11. ) Sep 18, 2017 · At idle the fuel trims are around -10. ) not a " fuel trim code" but P0430. Driving around the block the truck ran great, revved up to 4k rpm, long-term fuel trim stayed around 10-12%. Solution: You’ll have to hook up a scanner tool like BlueDriver to check out what your Mar 17, 2020 · The engine warms up as soon as it is started, and the long term fuel trim (LTFT) gradually increases to 21. Rev the engine to 3,000 rpm for 30 seconds and watch the short-term fuel trims. 5 on both short and long term fuel trim before (at WOT). Do this test. This number appears to be connected with the temperature of the air coming into the intake manifold - on days when it's particularly hot outside, we can see that LTFT creeps up further still, reaching a peak Jan 9, 2018 · This is constantly switching around. Dec 15, 2016 · 2 banks = 2 short and 2 long term fuel trims. Have an 05 E with a 3. Jan 1, 2020 · If the fuel trims spend about an equal amount of time adding and subtracting, then the overall fuel mix is stoichiometric. . So, is the post-cat lambda dead? Oct 3, 2020 · The proportion of unmetered air from a vacuum leak to metered air is higher at idle and lower at revs. 6 driving about 40-50mph Long Term B2 10. unmetered air (intake snorkel leak, other loose fitting vacuum hosesgoogle cigar smoke test for more info) Nov 23, 2018 · Long and short-term fuel trim are very useful indicators of engine performance, This post goes over exactly what they are, and what they tell you. Well I checked the PCV valve, changed the grommet and changed the tubing going to the TB. I replaced every single rubber tube, plugs, ccv, disa, all the usual stuff, and still had high multiplicative fuel trim on inpa at around +10 on both banks. STFT (0) to (-2) on average. 0L engine for your kind consideration, please advice why my LTFT remains in -ive though MAF, Intake Air Temp sensor, ECT sensor and O2 sensor is work Dec 15, 2016 · 2 banks = 2 short and 2 long term fuel trims. 90 Toyota 4Runner 1UZ-FE V8 engine swap. I did a quick check for vacuum leaks or cracked hoses. ST hovers between -1% and +3%. Using either brake parts cleaner (the flammable kind) or propane (put a tube on a small torch) spray around the engine and engine compartment where you have any vacuum lines or the intake manifold. #4 · May 13, 2022. It determines how the ECU controls the engine's fuel delivery. That's been consistent and filling up doesn't seem to change it. 7:1 A/F. That's with the engine fully warmed up. When running at highway speeds the trims are around zero as should be expected. (as fuel pressure is used up by higher RPMs, pressure in the rails goes down, this is a sign that there's too much pressure overall in the fuel rails. Throttle position: 18. At Idle you should see close to 0 once it settles. 1670 posts · Joined 2006. The long term fuel trims job is to keep the short term fuel trims at 0%. 9 when the engine is at idle. mileage is down a lot. -scans show long term and short term fuel trim on Bank 2 to be very high, LTFT2 pegged at 25%, STFT2 near 20%, and increases with higher RPMs Fuel trim is critical when it comes to diagnosing lean and rich conditions. ; Jumps to 900 after in gear and load applied. If long-term fuel trim (LTFT) for bank 1 is 25% at idle, but corrects to 4% at 1,500 and 2,500 rpm, focus on factors that cause a lean condition at idle Jul 25, 2021 · The basics on long term fuel trim is that the ECU uses data from the MAF, intake air temp (IAT), coolant temp, and O2 sensors to try and keep the engine running clean and efficient. possible causes: MAF dirty. So to start off, I have a 2002 Ford Taurus SES. If I swap for a new sensor, the short term trim values go up to 30% even as high as 40% and the long term values typically drop to 0% and hold so steady that it seems it isn't trusting the readings Jan 20, 2012 · First thing I see is that on idle, my long term fuel trim is consistently negative. The ECU controls Air/Fuel mixture in order to maintain power, efficiency, and emissions. 585 /. 3%. #6 · Feb 17, 2008. Sep 12, 2023 · Running rough, high long term fuel trim. If the condition exists in all rpm ranges, the cause is more likely a fuel supply issue caused by low fuel pressure, a restricted injector or a defective sensor input I'm seeing high positive fuel trims at idle (20+) that go away as the rpms go up (or, to be precise, as the throttle plate opens, since the trims also go high when for example engine braking). P0171 was the code. Idles at 900 RPM with or without code but will idle at 600 rpm after code is cleared. Short term fuel trims are 0-2%. Some customers/ technicians may also notice that the vehicle has a MIL illuminated or possible rough idle after an injector replacement. Then ticking sound in idle a few minutes after running, was the EVAP Solenoid. 8% at idle will go to 25-27 at 2000 RPM. If you had the engine at idle when you looked at the LTFT you most likely had a vacuum leak. (sometimes goes to 32+ and check engine lights as seen in the Freeze frame data. Nov 18, 2017 · A vehicle's computer system uses Fuel Trim to help maintain the ideal air/fuel ratio for complete combustion (stoichiometry) - 14. 3l V8. Vehicle performed the same after a/f sensor install. Fan cycles fine between 95C and 100C (A/C off) Checked O2 sensor reading and voltage cycles between 0. I temporary taped the intake boot at idle fuel trims are better long term 6. You have to do this carefully . Thanks! Scott. That's good to know. A dirty MAF sensor will take more power to heat suggesting a higher air flow that was it really occuring. Sep 10, 2014 · Fuel trim should be checked at idle, at 1,500 rpm and at 2,500 rpm. 118° LSA . Test operation of front and rear O2 sensors - the front should switch high and low in the range of 0-1V, and the rear should maintain a relatively steady 0. 2-3. O2 sensor bank 1: seems ok. 5. long term are 25% bank 1 and 100% bank 2. I know I can increase fuel modifiers to lessen the learning curve. 3% and bank 2 10. With age, they wear out, the ECM may receive improper feedback and cause fuel trims to be out of spec. Dec 4, 2013 · If long-term fuel trim (LTFT) for bank 1 is 25% at idle, but corrects to 4% at 1,500 and 2,500 rpm, focus on factors that cause a lean condition at idle, such as a vacuum leak. 0. Oct 10, 2019 · Long-Term Fuel Trim (LTFT) is a longer-term average of what the engine computer has been doing to balance the fuel mixture over a predetermined interval of time. However, I can see O2 bank 1 sensor 2 and O2 bank 2 sensor 2 at same time. By addressing these issues, you can maintain a balanced fuel trim and ensure your engine runs efficiently and smoothly. Im thinking there is a vacuum leak and it gets worse when the engine gets hotter. 8 idle, 14. I had read that over 10% was bad, and given the bad mileage I thought 19. If the front sensors switch normally, and the rears stay low, generally At both idle and 2500 RPM, after engine warm up, the post-cat short fuel trim is hovering about 50%. As I increase throttle to 1500 rpm, then 2500 rpm and higher, short term fuel trims will drop down to ~2 or 3%, close to zero. 2PSI average. A vacuum leak has a significant effect at idle speed while a fuel delivery issue is less of an issue at idle. Replace a clogged air filter. I don't have any check engine lights but I still have the pinging noise (i think) between 1500-2000 rpms only under load. Bank 2; 3. now have 52 psi @ idle; however the lite has returned. The only symptoms are sooty exhaust and high fuel consumption (27 mpg even taking it very easy on the motorway), and a slight hesitation when accelerating hard from 3000rpm Nov 27, 2013 · Fuel trim. Use the information to target the next diagnostic steps. I let go of the throttle (moving or standing, doesn't matter) it Feb 6, 2018 · Since the long-term fuel trim seems to go high at idle, a vacuum leak is the thing I would suspect. Indicating a bad signal from the air/fuel ratio sensor, spec is 0% + or - 5%. A few days ago I replaced all the head gaskets, and lower intake gasket. 1 above shows the fuel trim data collected on a vehicle with the Aug 22, 2023 · A Long Term Trim Stuck at 25% means more fuel is going into the cylinder air mass. I don't know much about fuel trims but from quick reading Aug 11, 2013 · High positive LTFT long term fuel trim. 3 driving about 40-50mph My rpms at idle RPM fluctuate 606-646 all different numbers. Positive fuel trim, no air leaks, confused was created by Drunken Elvis. Three way Catalytic converters need the mixture to be constantly driven rich/lean around this ratio in order to work at maximum efficiency. Thought I had it licked but I went for a little bit longer drive and it started doing the same thing again. Long Term Fuel Trim (LTFT) – Cars long-term reaction, which will change over time-based off how the short terms are doing. While the sensors’ signal will fluctuate frequently upstream, where Feb 5, 2023 · The check engine light came on about 2 days ago. To do a "hard reset", pull the negative side battery terminal and leave it off for 30 minutes. 4 and dropped at 2500 rpms for 30 seconds to 10. In this video I am going to explain how your short and long term fuel trims are calculated, than we'll try to diagnose a problem on a 2003 F150 with a 4. The purpose of the LTFT is to get the air/fuel ratio back to stoichiometric (in the event of a fault/normal wear) so the STFT can again cycle between rich and lean operating conditions. Bank 1 is around 15. With these four steps, you should be Jun 25, 2023 · The P0172 code indicates that the powertrain control module (PCM) has detected a rich air-fuel mixture in the engine's bank 1. I cleared it thinking it might the extreme cold air we were having. When revving the engine the long term drops below 10 but gradually recovers to 25ish after idling a minute or 2. 05 and 0. Fig. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Dec 4, 2013 · If long-term fuel trim (LTFT) for bank 1 is 25% at idle, but corrects to 4% at 1,500 and 2,500 rpm, focus on factors that cause a lean condition at idle, such as a vacuum leak. 2% . At idle, short term fuel trim was negative, and on throttle, it went Mar 15, 2021 · Diagnosing high positive fuel trim. I had fixed all the vacuum leaks, so I started looking more closely at o2 sensors and maf. long term goes from -20 around idle to ~-3% above 2krpm. Feb 11, 2013 · Check long-term fuel trim values. Checked everywhere for a vacuum leak and couldn't find one. 3 volts pretty steady at both idle & 3,000 RPMs. 1 cruise. 5 seems normal to me. I don't believe this is Mar 9, 2023 · Bank 1; 3. 10. 5V-0. For example, while LTFT B1 normal range Feb 26, 2019 · Just installed a 35780 kit and 17401 fuel regulator on a 425 HP Chevy. Started her up, and got P1151 and P1171 codes. 2006 Chev Malibu 2. 2005 Camry XLE, 3. Apr 1, 2015 · ISV cleaned a couple of times. The rough idle has greatly improved but seems still idling some. I will try to replace the MAF with a new OEM sensor and take another reading. 3. ) MAP: 5. It is used to diagnose immediate issues with the engine’s fuel system, such as a sudden change in the air-fuel ratio due to a sensor malfunction or a fuel injector problem. 0L - 190K. To compensate for excessive fuel, the engine computer (PCM) adjusts the air/fuel ratio (long-term fuel trim) to negative Jun 22, 2022 · The front O2 is the AF. 5 can run out and check their warm idle fuel trims to compareidle around 25 LT and 0-5 ST. It was recently mapped and Duncan noticed it was running rich, but was unable to lean it out without causing running issues. LTFT is at 14. 212 posts · Joined 2007. First clue of a problem was after idling in a parking lot for over an hour - stalled out when I put it in reverse, but after a Nov 20, 2016 · That is where the long term fuel trim kicks in. (Neg=rich. Sep 26, 2022 · Negative long-term fuel trim is most commonly caused by a problem with one of the engine’s sensors. Issue is specific to idling for long periods, like 30+ minutes (unfortunately, this is not something I can avoid doing semi-regularly). 9 (idle) 15. May 28, 2024 · A change made to the fuel delivery changes the long and short term fuel trim values. Positive numbers indicate the addition of fuel (lean correction) while negative numbers indicate removal of fuel (rich correction. Coolant temp around 185F. If this happens, it can lead to skewed Long Term Fuel Trims (LTFT) and/or Short Term Fuel Trims (STFT) during engine operation. So, let’s focus on short-term fuel trims. I believe people experiencing that problem have enlarged the idle air passage to help. Dec 21, 2021 · well when running the code scanner the long term fuel trim in bank 1 and 2 are high at idle. At this point, my OBD2 reader shows a STFT of about -16% which completely negates the LTFT. 585 . Here's what's happening. Mar 12, 2019 · My question is can a partially malfunctioning low efficiency catalyzing catalytic converter cause a low O2S2 voltage that results in a high long term fuel trim? Mar 20, 2014 · replaced the Fuel press reg with a unit rated to 65 psi. The normal LTFT B1 range should be 0 or numbers near 0 if all components work fine in a normal engine working condition. kr xj je io pv sv mf eq aa uc