erratic fuel trims If STFT is greater than approx. Fuel supply pressure below 50 PSI can cause a low power or hesitation problem. P0099 Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic P0169 Incorrect Fuel Composition P0170 Fuel Trim P0171 System Too Lean P0172 System Too Rich A fuel pressure tester will be used to determine whether there’s a problem in the fuel pressure or not. May 18, 2017 · Fuel trim is the correction the PCM makes to try to maintain a stoichiometric air-to-fuel ratio. Cells 20,21,22 are used by the VCM when it does not want to make a permanent correction to the VE table values (examples would be Decel Fuel Cutoff, Power Enrich Fuel, Charcoal Canister Purge off). Now I Jan 17, 2014 · Now my last thing which I did, half by coincidence, half to rule a fuelling problem out, is change my fuel from VORTEX 98 (local Caltex Australia brand) to United 100RON. Vacuum leak, bad oxygen sensor, fuel leaking from fuel pressure regulator into manifold, failed fuel injector, bad coolant temperature (ECT) sensor, bad manifold pressure (MAP) sensor, bad mass air flow (MAF) sensor. For us, our long-term fuel trim went from 19 percent at idle and slowly dropped to about 5 percent at 2,500 rpm. This is to confirm the sensor’s quality and performance. At both idle and 2500 RPM, after engine warm up, the post-cat short fuel trim is hovering about 50%. Dec 10, 2015 · P0170 Fuel Trim Malfunction (Bank 1) P0171 System too Lean (Bank 1) P0373 Timing Reference High Resolution Signal A Intermittent/Erratic Pulses Non E85 Flex Fuel Vehicles September, 2013 Technical Bulletin #1557 4L60E Harsh Shifts, Misfire Codes, Wrong Fuel, Fuel Trim Codes All Flex Fuel vehicles are designed to run on gasoline and E85 fuel. When a code P0172 is set, it means that the Fuel Trim is anywhere from -15 percent to as low as -30 percent compensated. Jul 23, 2020 · Ever put a lower octane fuel in your gas tank than what the manufacturer called for? An octane rating is the fuel’s resistance to detonation via compression. It has to remain in this zone under all the various conditions an engine encounters every day: cold start-up, idling in heavy traffic, cruising down the highway, etc. 6F35 Code (DTC) P0170 Fuel Trim Malfunction (Bank 1) 6F35 Code (DTC) P0171 System Too Lean (Bank 1) 6F35 Code (DTC) P0172 System Too Rich (Bank 1) 6F35 Code (DTC) P0173 Fuel Trim Malfunction (Bank 2) 6F35 Code (DTC) P0174 System Too Lean (Bank 2) 6F35 Code (DTC) P0175 System Too Rich (Bank 2) 6F35 Code (DTC) P0217 Engine Overtemp Condition Jan 31, 2018 · Check the fuel trims and O2 sensor values on a scanner with a graphic function. Nov 27, 2018 · A P0171 FUEL METERING TOO LEAN code can mean the engine is getting too much unmetered air or too little fuel. P0442- Not concerned for fuel trim and stall problem P1537- Fixed by vacuum hose not attached to intake manifold running to IMRC solenoid I already cleaned the MAF sensor which was a little dirty and TB and cleared CEL. I'm thinking of doing the same with my w202. Installed new factory 02 sensors. If equipped, the OEM fuel pulse damper (shown above) can be reused with the Radium 14-0278 adapter fitting. These then appear typically as a PO136 or P0137 code for anyone using an Ford 6R60/6R80 Erratic Transmission Temperature Ford 6R80 Low-Reverse Clutch Clearance Procedure Ford 6R140W Bind-Up On The 1-2 Shift Ford 6R140W Center Gear Case Change Ford F150 Rattling Sound From Bellhousing Area Dodge C635 No Engagement 62TE Missing Caged Needle Bearing FCA 62TE Slipping in Second & Fifth Oct 16, 2019 · Most Jeep Wrangler owners like to push their rigs to the limit. For gasoline, that’s about 14. The ECU checks ignition, fuel trim, cat efficiency, lambda sensors, PCV valve operation and EVAP purges. I have spent countless hours going over the engine looking for vacuum leaks and believe every thing is OK on that front. MIL is constantly on, sometimes flashes. During engine operation, the thermostat actually never fully closes or opens, but gradually nears either state to control coolant flow. After all that I copied  Here is an explanation of fuel trim and what it does for us. Im getting negative fuel trim readings accross the board. 32 for B1S1, 0. Please advise if (LTFT = long term fuel trim) And if there is some leak you will have erratic idle possibly. 6% MAP 10. When the code says that the Fuel System is "too rich," it means that the computer has been subtracting more and more fuel, which is called Long Term Fuel Trim. Refer to the short and long term fuel trim data on your scan tool. 7:1 for example) or as a Lambda Fuel trim values will decrease if the PCM thinks or knows the vehicle is running rich. So, leads me to believe the fuel canister and/or the purge valve, since they work hand in hand. Vacuum leaks, a dirty or bad MAF sensor, low fuel prssure, a clogged PVC system, bad injectors, a bad temp sensor, a bad or slow upstream 02 sensor are all causes of erratic fuel trims. 00 all the way across. You can see that #3 is right after #4. look at live data read o2 feedback & fuel trims etc Jan 16, 2013 · Drive the car in 3rd or 4th gear with an engine speed of between 2,000 and 2,500 rpm for 3 1/2 miles (no hard accelerating or erratic shifting). So for example if we look at bank one, long term fuel trim at the moment, bank one is in red and you can see that sitting at minus 3%. As part of the investigation, it was found that the inaccurate levels were due to problems with the resistors in a circuit of the sender unit. P0168 Fuel Temperature Too High P0169 Incorrect Fuel Composition P0170 Fuel Trim Malfunction (Bank 1) P0171 System too Lean (Bank 1) P0172 System too Rich (Bank 1) Making the fuel mixture artificially rich by feeding propane into the intake manifold should cause the sensor to respond almost immediately (within 100 milliseconds) and go to maximum (0. My AFR gauge has been reading rich at idle -  My fuel trim thread/diary NA Engine (non-turbo) / Drivetrain / Exhaust I'm leaning toward leaky injectors or failing FPR because of the often erratic and/or hard  16 Aug 2019 Check fuel trim with a scan tool: This test only applies if the engine is running. ) Recently rebuilt the 454 in my 1990 TBI Burb. I bought a fuel pressure gauge today. May 29, 2016 · The pre-cat (upstream) O2 sensor basically regulates fuel trim. Like mass air flow, crankcase breather or fuel delivery. May 28, 2020 · DETECTION CONDITION • The PCM monitors the target A/F fuel trim when under the target A/F feedback control. Stored fuel-trim numbers may not be as reliable as we’d all like, because a misfiring cylinder acts as an air pump and drives O2 sensor voltages very low. Vehicle belongs to a youngster at work. It is common to see the ECU trim out fuel in response to environmental variables, here is an example: No change. The misfiring took place while driving, around 40 mph. To maintain the correct air/fuel ratio the engine controller Oct 02, 2020 · The fuel pump receives the fuel from the fuel tank and throws it into the fuel rail which transfers the liquid into the cylinders using the knowledge of the fuel pressure sensors. Mar 12, 2019 · Thermostat Illustration. This was just a normal If it's really erratic then it's likely the sensor. In order to detect clogged injectors, some engine management systems incorporate a scan tool-based injector test that measures a drop in fuel pressure when the PCM pulses a selected fuel injector. Far more data needs to be provided and I need to understand what software or tool you are using to gather data and clear Fuel Trims. GM states that the normal short term fuel trims are The fuel pump is a device that moves fuel from your tank to the engine, supplying the fuel at a constant pressure to ensure that your engine runs smoothly. First, an air metering issue can sometimes cause slightly negative fuel trim numbers at lower RPM. A road test was carried out and the vehicle misfired intermittently, more so under load. This correction can be measured throughout the RPM range and can often help an erratic surging idle. Fuel-trim-related code(s) Excessively rich or lean idling, often causing black smoke from the tailpipe. If you choose to follow any of these How-2’s, please do so at your own risk and do one change at a time…in other words, Mar 14, 2014 · So long-term fuel trims are semi-permanent adjustment to the base map, while short-term fuel trims are adhoc adjustments to the base map. Loss in performance is a sign that this might be happening. Some fuel pressure regulators are vacuum modulated, and so would jump to high pressure when vacuum is lost. The post cat sensor is a cat performance sensor, so it checks to make sure the catalytic converter is working properly. fuel, spark mixture. Normal range is typically plus or minus 8. Default number is 128 (which is 0%). Short term fuel trims should vary as your drive the vehicle. When ignited, the flame front can be erratic, leave unburned fuel and create hot spots in the combustion chamber. com Most technicians understand the concept of fuel correction and what we mean by “closed loop” operation but just in case… Fuel control is the concept of maint Short Term Fuel Trim (STFT) -- The correction factor being used in closed loop by the PCM to maintain a balanced fuel mixture. 1L Workhorse W24 65k miles (all data while parked) coolant temp: 195 F RPM:605 - idle STFT1:+/-2 0 avg STFT2:+/-2 0 avg Fuel Pressure. Note that some vehicles are designed to run multiple octanes. If I reset the fuel trims and erase the codes, then start the engine cold, fuel trims behave normally until the engine reaches operating temperature at idle. 2009 X5  9 Jan 2018 Meaning that the RPMs are not fluctuating, and its steady. When Monitored and Set Condition: Car problem question: I scanned my 2002 Taurus 3. 2% I'm not sure but I think that MAP is a little low. 2002 ford explorer 4. A/F is expressed  General Ford Ranger Discussion - Very High Fuel Trim & Pinging - Hi all, I plugged the 'ole scan tool in and noticed erratic ignition timing - see attachment. Last Post 22 Dec 2014 14:47 Oxygen Sensors & Fuel Trim. 5%. Sep 14, 2016 · Fuel trims should be within 5% or so of 0. thanks Jul 10, 2017 · The driver had no warning because the low fuel light didn't illuminate. com Timing chains connect an engine's pistons with the intake and exhaust valves. Ideally the fuel trims would stay around +/- 5% all the time, but with an email tune the odds of that happening are Apr 28, 2011 · - Erratic idle, appears when warm, worst after a hot/warm start - Severe hesitation and missing, appears when warm, worst after a hot/warm start - Occasional stalling after warm/hot start. 1st after market, 2nd a ford assembly, found cracked fuel hose, replaced, Extreme hesitation, interment. Nov 21, 2014 · The normal fuel trim value for both Short Term Fuel Trim and Long Term Fuel Trim is typically plus or minus 8 with 0 being ideal. 78 volts with no fuel trims while the other bank's O2 jumps wildly from . The fuel pressure regulator is an engine management component that is found in one form or another on virtually all internal combustion engines. Topic started, 10 Dec 2014 18:00, by JV. 65 lb/min Throttle Position Angle 0. Got as low as 5% but again didn’t stay that way for long. Car problem question: I scanned my 2002 Taurus 3. Short term fuel trims can get as bad as pegging -25% at idle with long term reflecting the trend, usually sitting at -15%. While if u had done some ultra sonic cleaning of injectors or used some aftermarket injector cleaning agents in fuel tank than chances are they will go bad after 150K kms. Fuel trim should be checked at idle, at 1,500 rpm  24 Jul 2016 Help with erratic fuel trims e38 after tune. Short term fuel trim, or STFT, is the correction that occurs right now. 2 l ,2005, engine code z12xep. 85-3. Fuel trim is being discussed. What can cause ALL these problems??? erratic shift points and shift 'hardness' or softness (automatic). However, a vac Making the fuel mixture artificially rich by feeding propane into the intake manifold should cause the sensor to respond almost immediately (within 100 milliseconds) and go to maximum (0. in live data bank 1 long term fuel trim reading -25%, and bank 1 short term fuel trim -16% up to -20%. A high voltage, say 0. Jan 22, 2014 · Heads/Cam/Headers LS3 Vette. 20 Dec 2012 Any ideas what is causing the short-term fuel trim to be so erratic shown in the graph? (lower graph line in red) 99 Ford Explorer 230K miles 8 May 2019 It is completely erratic and I can not make any sense of it, sometimes I'm actively data-logging) you do see fuel trims are all over the place. The car is not throwing a code, and I don't believe that there's a hole in the exhaust but I am open to correction. So if the trim is maxed out, the ECU is adding 27. Currently at idle, my STFT are 14-17% with long term at 25%. He notified me that the vehicle had began to “run funny” for him and I agreed to analyze the vehicle over the weekend. If there’s a serious fault in the MAF sensor circuit itself, you may find a P0101, P0102 or P0103 code. Fuel trim’s adaptive strategy consists of two components: short-term fuel trim (STFT) and long-term fuel trim (LTFT). excess unburnt fuel, aside from hurting your mpg and wallet, can damage the cat converter in the long run. My 2002 BMW 745i (E65) has an erratic idle What could be the cause. This diagnostic fault code is a generic powertrain code, which means that it would apply to the OBD-II equipped vehicles. Gross fuel trim failure are common and have multiple causes. . bouncing between maybe -1 up to 3. You can start with injectors cleaning solution added to the fuel tank or even better if you remove and clean injectors individually. Engine light came back on. Only thing I noticed on the display was the MAP went from 9. Short term fuel trim is the short-term fuel compensation used to maintain the mixture ratio at its theoretical value. Check codes. Long Term Fuel Trim makes slower more permanent changes. 2% seems kind I guess the fuel trims values are alright at 2120 and 3285 RPM and not correct for idle, perhaps something wrong at idling, however there is no erratic idle present. Jens von Holten, owner, and Tim Jilg, general manager of Fuel Injector Clinic, knew these injectors would be a challenge and since I would be tuning the Evo myself, they saw this as an opportunity to assist them in the development of new flow bench testing strategies to further improve the matching process of high flow fuel injectors in the nonlinear injector pulse width (IPW) operating range. Fuel trim data is way cool, since it tells you what the PCM is having to do to keep the air fuel ratio where the PCM wants it to be. Will replace that and go from there. Low fuel pressure results in a lack of horsepower, stalling, and a slow or no-start condition. All XJ Non-modified/stock questions go here - positive fuel trim - Hey, I've got a thread going about P0171 but I want a little more detail  I have done some reading on Fuel Trims and everything appears to be as expected. DTC P0300 Random Misfire DTC P0171 Fuel Trim System Too Lean. Fuel Trims going Erratic. The codes I get are cylinder 1,3,4,5,6. You have to look at what would affect fuel trim over the entire load. The check engine Trouble Codes › OBD II Trouble Codes. If you can monitor the engine parameters with scan tool set up the fuel trims only and while rapping on the purge valve see if there is any change in trims that might indicate a sticking valve. This is only at idle, while running on the interstate, the long term trims back off to around -10% (short terms zero out). O2 S Sh t d tO2 Sensor Shorted to Voltage. 28 May 2013 It uses your scan tool to watch the fuel trims and the downstream O2 sensors. This could result in fuel trim problems and a check engine light, possibly with Fuel System Rich DTCs, such as P0172 or P0175. You have a modified Sonic, so seeing that the car is asking for more fuel at times makes sense. Remove the lower panels to gain access to the relay box. 0t FSI’s fuel injection works the gunk can buildup overtime on the valves by oil and junk flowing through the PCV system to the valves. What remains the same is that fuel trim numbers increase as RPM increases. I am randomly getting erratic MAP readings, which I think is causing the short term fuel trim to go negative sharply, all the way to -27%. hello ,I am in need of some fuel trim numbers ,I can see the numbers on my scan tool but they seem really erratic . Wideband was not connected on this run. 2. Mar 26, 2012 · Fuel trims going erratic when car gets up to temps. 0 Hg Engine Speed 574. Ford fuel pressure regulator VACUUM LEAKS Another common cause of Ford P0171 and P0174 ean codes is an engine vacuum leak. Any Insight? elirentz: Engine Management & Tuning: 11: 10-17-2007 01:10 PM: Circumsized Stock Injector Fueling - Rock Steady Idle - Perfect Fuel Trims - FREE map: MRF582: Engine Management & Tuning: 88: 10-02-2007 06:42 PM: Important Q: Regarding Short Term Fuel trim at Idle! BlueDemon But my fuel trims are STILL everywhere. 68. As on schedule it started to act up about 5 minutes after startup. A kink in the fuel return line results in higher than normal fuel pressure at the rail. Connect your scanner, making sure that all of the information relating to the proper model, engine and equipment is entered. too much fuel and so the trim is reduced. Mine reads 50 psi. If it is presently stumbling at idle it should show up on the fuel trims. Jul 12, 2007 · Short Term Fuel Trim in general makes very quick and small temporary changes to the fuel being delivered to the engine. fault code stored is p0170 fuel trim malfunction bank 1. Dec 16, 2011 · Post subject: Re: Erratic fuel trims rich idle. 13 Sep 2015 Running rich fuel trims to -40 S-Series Tech. 7. Posted: Fri Dec 16, 2011 7:09 pm . Before assuming it. Ask your tech to look at the Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT) values. MAF (Mass air flow) replaced, fuel pressure regulator replaced. Took care of the erratic idle I had. When the fuel pump relay goes bad it will trigger many fault codes with electrical shorts to ground. May 28, 2020 · I have 2006 Dodge Ram 1500. 10 to 12, the engine is running LEAN. That is, if a lean Diagnosing the Erratic Shifting Ford's 8F35/57. 0 hour of labor. On fuel injected engines, cold stalling can also be caused by conditions that upset the air/fuel mixture. Hard Start/Long Crank/Erratic Start/Erratic Crank. Now I Integrator (Short term fuel trim). Short term fuel trim in bank 1 = 25% and Short term fuel trim bank 2 = -25% at 2500 rpm   14 Dec 2016 1997 - 2003 Ford F150 - Fixing high long term fuel trim - At idle, bank 1 9%, bank 2 14%. Scan your codes and follow the chart to determine what the code means. I could be wrong. I'm not trying to figure out my fuel trims. It's semi-permanent as you can reset these trims by resetting the factory ECU (full power-down). 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. Being able to interpret your scanner Fuel Trim Data requires a basic knowledge of the interaction of Short Term Fuel Trim and Long Term Fuel Trim data. Learn about this problem, why it occurs, and how to fix it. Please see the Close Loop and Open Loop also. At WOT some cars can drain their fuel tank in just minutes. The fuel map is a two dimensional table of values, sort of like an Excel spreadsheet, for how much fuel to squirt, based on engine RPM and load value. Vehicle: 2011 Ford Crown Victoria, V8-4. Worst case is under WOT. But afterwards the long term trimming catches up. Mar 28, 2017 · If you have access to VCDS you can identify if the engine is running mean lean by studying Long Term Fuel Trim (LTFT) and Short Term Fuel Trim (STFT) in Block 032 and 033. When the fuel mixture is rich (less air, more fuel), an O2 sensor produces a high-voltage signal of 0. 8 to 0. How to Do an Idle Relearn. There was no codes but my long term fuel trim (LTFT and Short Term Fuel Trim (STFT) are over the limits (should be +10 or -10) when I rev the engine up. We also talked a bit about the factors that can cause fuel  5 Feb 2018 For almost 2 weeks now, I've been having fuel trim issues. I just finished putting in a new OEM disa. If the numbers are +10 or higher for STFT and LTFT, the engine is running LEAN. 615"/. <<See All OBD Codes. Apr 27, 2014 · One of the major contributors to abnormal and erratic fuel trims, I believe, is Mass Air Flow (MAF) Sensor placement! So let's have a look at this interesting topic! There are four places you could possibly put the MAF Sensor when you add a turbo to your monster. Mar 11, 2019 · Slight erratic, intermittent idle due to misfire. Have a beer and study these videos! • FMI=2 - Data Erratic, Intermittent Or Incorrect • FMI=3 - Voltage Above Normal, Or Shorted To High Source • FMI=4 - Voltage Below Normal, Or Shorted To Low Source • FMI=5 - Current Below Normal Or Open Circuit • FMI=6 - Current Above Normal Or Grounded Circuit • FMI=7 - Mechanical System Not Responding Or Out Of Adjustment Jul 07, 2020 · Wires that are broken, melted against the hot exhaust pipes, or corroded, will give erratic or missing readings. Fuel trim should be checked at idle, at 1,500 rpm and at 2,500 rpm. P0172 Fuel Trim System Too Rich. Determine total fuel correction for bank 2 of a V-engine, by adding LONGFT2 to SHRTFT2. It, too, should be close to zero,  19 Sep 2006 Your Long Term Fuel Trim from your sensor 1 is reading way Also check for exhaust leaks, which can make your sensors reads erratic. Initial idle was a little erratic, but after a few seconds the idle settled in to a more constant RPM and the fuel trims began to "learn". May 08, 2014 · First, check fuel trim data on your scan tool. 18 May 2017 In a way, fuel trim is line a “crystal ball” that allows you to see what the PCM is trying to do. So, is it just detonation that will do damage, and if I can quell that by retarding the timing, will my engine be OK? What I am worried about is overheating by running lean (>14. I don't know if maybe it was a partial issue with both since I changed them at the same time but air data was not being read correctly and now is. My question is at idle LTFT is -7% and STFT is -0. When the cat is restricted, the downstream o2 will show bad readings. If the fuel trim is less than the specification, the PCM determines that the system is too rich. All of the vehicles tested had +8 to +10 long term fuel trim. Fueled up with Shell 93, from a station I  15 Mar 2019 What are fuel trims? When a petrol engine runs with a stoichiometric air/fuel mixture (14. too little fuel and so the trim value is increased. Take a look at the log. Ugh. I'd like to share my graphs that I prepared today. It all started ( I think ) Wednesday before last. with a bad misfire on 1 and 2 cylinder I replaced the spider and the pressure regulator. 52 for B2S2. 70. ca: P0222: TP sensor No. Diagnostic support note • This is a continuous monitor (fuel system). A high output engine running at WOT uses a ferocious amount of fuel. Because the oxygen in that cylinder isn’t burned up, the extra oxygen in that cylinder winds up passing over the O2 sensor. Technician B says LTFT [long-term fuel trim] is erased when the ignition is turned off. A… Aug 12, 2018 · P0503 - Vehicle Speed Sensor 1 Erratic P0506 - Idle Speed Performance Lower Than Expected P2096 - Downstream Fuel Trim System 1 Lean P2097 - Downstream Fuel Trim Sep 09, 2020 · This allows the PCM to adjust the air/fuel ratio whenever necessary. D. 0 The cost to diagnose the P1129 code is 1. The cross-over point where the output voltage suddenly changes from high to low or vice versa occurs when the air/fuel mixture is perfectly balanced (14. During the misfire event, all the data was fairly normal. Then long-term fuel trim spikes to −35 in about 30 seconds. 1v-0. But not the misfire. 4 Apr 2015 Ive used Torque Pro to pull LT and ST Fuel Trims. 5l Idle Surge – Erratic Idle 20 July 2012 6:38 PM | 1 Comment; 2005 BMW 325 P0171 P0174 227 228 Fault Codes Dinan Stage 2 15 June 2012 8:13 PM | 1 Comment An engine that is misfiring because of a bad spark plug, weak coil, dirty fuel injector, leaky valve, or vacuum or EGR leak, may cause the catalytic converter to overheat and suffer damage. After refuelling I did an Adaptation 00 Reset with VCDS to reset all learned value (including fuel trim) to factory settings. The Ross-Tech VCDS PC-based Scan Tool example to the right shows that the PCM had stored And if there is some leak you will have erratic idle possibly. Like this. ) Here is an explanation of fuel trim and what it does for us. upstream systems in order to be valid. No Monitoring long term fuel trims on a scan tool will also reveal ignition related problems. The lambda sensors for closed loop operation are narrowband. 95 volts at WOT; check floor mats or a bad throttle assembly . The intervals of opening and closing are very short -- from one-fifth of a second when idling to two hundredths of a second at 5000 rpm -- so small problems can seriously affect engine performance. 7 parts air to one part fuel, or 14. The fuel pressure, the injection time, short and long fuel trim data, which actuators are on or off, if the fuel pump is working or not, readings coming from the O2 sensors as well as, misfires counts and even how the PCM is behaving to try to correct the situation are all valuable information. 53 for B1S2, 0. Next set Short Term Fuel Trims & Long Term Fuel Trims to Disabled or set their limits accordingly. If the O2 sensor says the exhaust is too rich (too much fuel) the ECU will reduce pulse width of injectors to subtract fuel. Fuel Trim Fuel Trim Case Study #1 A 2000 Audi TT Quattro came in with a complaint of an erratic idle, intermittent stalling, and an illuminated MIL. 8 RPM MAF Air Flow Rate 0. Fuel trim includes short term fuel trim and long term fuel trim. 4 at idle, only oscillating very minimally, I'm talking by maybe +/- 0. This number changes rapidly when operating in closed loop as the computer is constantly adding or subtracting fuel based on Jul 20, 2011 · TEST 3: Testing The 2nd Ground Circuit Now, we'll check the second Ground Circuit of the MAF sensor (this is known as the MAF RTN circuit). subject regarding erratic fuel gauge reading ok. The fuel sensor is sampled every second and averaged with the previous 30 samples. g. Jun 16, 2017 · Results were no improvement, actually worse hanging at higher rpm now but now I'm getting legitimate data about the fuel trim. OBD-II introduced a standard terminology for the amount of fuel added or removed from what the fuel map suggests the vehicle will need at a given time, called " fuel trim ". 4. So you want to see if the PCM is trying to add fuel. Oct 30, 2020 · At the 3/4 full fuel level and below is when you get this erratic operation and stalling. 67. 4 Evap Leak, Fuel tank pressure sensor fault P0451 23 July 2012 12:34 AM | 2 Comments; 2005 Nissan Sentra 2. This ensure Sep 09, 2011 · P2096-DOWN STREAM FUEL TRIM LEAN BANK 1 P2097-DOWN STREAM FUEL TRIM RICH BANK 1 P2098-DOWN STREAM FUEL TRIM LEAN BANK 2 P2099-DOWN STREAM FUEL TRIM RICH BANK 2 Test Note: All symptoms listed above are diagnosed using the same tests. Hard Start/Long Crank/Erratic Start/Erratic Crank The MS43 fuel injection maps are based on engine load over engine speed and the lookup value is injection time in miliseconds. it is definitely lean all the time. +- 5% total fuel trim is an acceptable range. Jan 25, 2016 · p007e charge air cooler temperature sensor circuit intermittent/erratic p0087 fuel rail pressure too low p22b5 o2 sensor 1/2 pump cell current trim circuit open Sep 24, 2019 · nhtsa id number: 10163665 manufacturer communication number: pit5569a summary this preliminary information communicates direction and examples when diagnosing multiple dtcs, one of which includes u**** byte 71 dtc. I've noticed at cruising speeds around 2500-3K rpms they are fairly consistent with STFT1 measuring around -2 to 2. 2003 Ch l t I l2003 Chevrolet Impala Basically, fuel trims are the percentage of change in fuel over time. See full list on mechanics. Your fuel trims should be down at less than 10% under normal conditions. runs erratic intermittent, have changed egr and air flow, but still fault occurs. A useful diagnostic tool is to determine if the fuel trim problem exists in more than one engine operating range. Gas gauge is erratic – GM Gas gauge is erratic – GM. causing the engine to run too rich, the spark plugs would not have a normal appearance and instead would become fuel fouled. An oscilloscope will be used to test the connectors and wirings of the fuel rail pressure sensor for vehicles with normal fuel pressure. Thread Tools. The engine is flicking from open to closed loop continually and the ST fuel trim reads randomly in the  2 Dec 2009 The Long Term Fuel Trims are reading and staying at 0 during idle. Changes to the LTFT’s do not take effect immediately – the PCM requires about 50 minutes or roughly 100 miles to allow for the PCM to relearn the fuel curve. It depends on the response of the O2 sensor. However, noticed when the bonnet was up that with look for fuel trims fluctuating with the wideband reading. 7:1. 63 for B2S1 and 0. This tells me there's a rich condition especially at idle. This will set all cells to a 14. Gauge name. I was checking my short term fuel trim numbers and o2 sensor switching speed as I think my post-cat sensor has degraded. Throttle voltage should be 3. 21 Jul 2018 Powertrain and engine control computers (PCM/ECM) employ a long term fuel trim delivery strategy that learns to self-adjust as driving  18 Nov 2017 I am trying to get a full (well, as mush as I can) understanding of the fuel trim data. stackexchange. These numbers go down as speed increases. 1% LTerm Fuel Trim B2 8. A faulty fuel pump or a clogged fuel filter causes lower than normal fuel pressure. P1175 - Fuel Trim Adaptation Additve Bank 2 Malfunction P2292 - Injector Control Pressure Erratic P2293 - Fuel Pressure Regulator 2 Performance P2294 - Fuel Sep 26, 2010 · Gross fuel trim failure. 1 to . I did have one bad stuck sensor replaced a very short time ago. Technician A says a positive fuel-trim value means the PCM detects a lean mixture and is increasing the pulse width to add more fuel to the mixture. They have a 10% window that will only affect the Long Term Fuel Trim (LTFT) if the fueling correction is beyond the 10% window for 10 seconds. A/F is expressed as either a ratio (14. The more fuel you give it at cruising, they work there way back to 0, but as soon as you stop, they're back to negative. Car is 18 years old and 250k miles. May 07, 2015 · The DTC P0172 code is relatively rare, and indicates that the PCM has had to reduce the long term fuel trim by more than -13% to -20% (depending on model year) for a prolonged period of time (e. 8 thanks It seems to go positive and negative ,,something seem not to be so good Feb 06, 2014 · Erratic idle or operation. Fuel pump Relay – The fuel pump relay is located under the driver’s side kick panel. Aug 13, 2018 · @superman07 I thought these had a filter that’s tied in with the pump or something g There is a cloth filter I believe in the tank protecting the Aug 20, 2014 · LT fuel trims are usually around 12-14% been as high as 20% but only briefly. I agree with what you said about it affecting both banks but you never know you might have more then one leaky injector. My fuel trim was erratic corresponding with the sudden drops in rpm and peaking at 20% when should be close to zero at idle. Hi, My emissions light keeps coming on and when I check the fault code it is always "fuel trim system lean" which I then reset and it disappears for a few weeks and then comes back again, I haven't touched anything under the bonnet for almost a year and cannot identify any vacuum leaks. Dec 12, 2005 · Fuel System 1 -CL-1 Calculated Fuel Trim B1 -3. Full list of OBD II Diagnostic Trouble Codes for your Vehicle. 2 circuit low input: ON: 1 Conditions: The PCM monitors the input voltage What is the cost to diagnose the P1129 code Labor: 1. Short term fuel trim is always erratic because it’s the real time adjustment for fuel delivery. Basically, fuel trims are the percentage of change in fuel over time. Sep 17, 2020 · Fuel Trim Info 8/29/20 2006 8. Here is the video on that: Cleaning Dirty or Clogged Fuel Injectors - DIY Without Using Expensive Equipment File>Connect. Fuel Trim Case Study #1. Long Term fuel Trims. In the event you are experiencing an erratic idle after loading a tune or after performing any action that clears KAM (Keep Alive Memory), an Idle Relearn can help you get back on track. When the early direct-injection engines hit the three-year or 30,000-mile mark, some developed driveablity problems due to carbon buildup on the necks of the intake valves. Lambda is 1 most of the time. During the misfiring event cylinder 3 was the worse followed by cylinder 4 with a few misfires on the other cylinders. stutters at idle. Rap on the purge valve to see if stumbling quits. 71. 9 volts (with more time spent  Fuel trim data shows bank 1 is running lean while bank 2 is running rich. Fuel with ethanol will raise fuel trims slightly as you'll need more fuel to reach 14. A clogged fuel filter often results in erratic engine performance by causing an abnormal or alternating pattern of fuel flow into a vehicle's engine. The average for my last run was 0. one bank's O2 sensor voltage varies from about . 8 to 14 and bounced around there. Unless your vehicle requires it, using fuel with a higher octane rating other than Regular will do nothing for the engine, but it will empty your wallet faster. They said that the fuel mix was too rich. The PCM starts out with a baseline fuel/air mixture that it believes will achieve a stoichiometric ratio. DTC P0172 Fuel Trim System Too Rich. Jun 23, 2018 · Change fuel filter as failing pump may have junked up filter. It has not set any consistant codes. I have been all over  Tuner noticed the differences in fuel trims from bank to bank and the tuning has been put on hold since he believes there is a mechanical issue  And with OBD II making fuel trim readings a part of every data stream, is there any great mystery as to what kind of mixture is going into the combustion chamber  27 Nov 2017 96 Camry V6, 176000 miles These are LONG term fuel trim values, dig. P0172 @ foxed. So, for instance, if you start going up a hill and need more fuel, if a vacuum line comes off and creates a lean condition, or if there is any airflow/fueling change in the moment, the STFT is there to assist. Subarus maximum fuel trim adjustment is something like 27. Normal range is plus or minus 8. The ECU measures the effect of the fuel trim adjustment by means of the O2 (sometimes called lambda) sensor. No change to trims although driveability has improved. For as I saw, the original owner had also removed the Flow  21 Aug 2010 sloshing will not cause erratic behavior. Long Term Fuel Trim ( LTFT) – Cars long-term reaction, which will change over time-  Fueling & Injection - Negative Fuel Trims - Hooked my car up to a scanner and read the real time data. In addition to these no-load checks, drive the vehicle at various steady load conditions and watch for fuel trim variation. If the fuel system is open loop, 0% correction should be reported. Replaced fuel pump and fuel filter. 3 l while driving home it started running rough and stalled out but would start back up but idles rough and when I put in gear it runs worse and stalls I found there was a fuel leak in the upper manifold and the fuel pressure was 53 psi. 4 motor is a tricky and complicated device. Also if the old converter came apart there is a chance that a part of it is still stuck in the exhaust somewhere and plugging the exhaust periodically. I have no codes. I have replaced the 2003 Hyundai Santa Fe 2. The ECU controls Air/ Fuel mixture in order to maintain power, efficiency, and emissions. Ford F150 Ecoboost Performance Parts and Tuning. Fuel trim is the PCM’s adaptive strategy that allows it to deal with these issues by adjusting the amount of fuel that is injected into the engine, but only once it is in closed loop operation. When the code says that the Fuel System is "too lean," it means that the computer has been adding more and more fuel, which is called Long Term Fuel Trim. If long term fuel trim percentage is high at idle, but drops down to nearly zero as the rpm rise up, this almost certainly indicates your problem is a vacuum leak. Whether that’s desert racing, extreme rock crawling, or water fording, there’s really only one thing that can prevent you from getting the most out of your Wrangler — the check engine light. IAC (Idle air control replaced. The short-term fuel trim (STFT) refers to immediate changes in fuel occurring several times per second. maxed out fuel trims. Apr 09, 2007 · The PCM uses the Short Term Fuel Trim (STFT) for real time fueling corrections. The dealer said that the code was cleared and all was in specs after the air filter was correctly installed. Nov 28, 2008 · IDLE TUNING The following is a collection of idle tuning notes, tips ‘n tricks and How-2’s for idle tuning a big cam (or any cam for that matter) that I used when dialing in my 248/254, . Here is a good basic test process for fuel trim faults such as P0170, fuel trim malfunction: 1. Nov 07, 2010 · Goto DVT tab, select GenIII LS1 99-08 PCM, goto Learning subtab, see Fuel Trim Reset. 6L Flex Fuel Mileage: 141,009 Problem: The vehicle was brought to the shop because the engine would intermittently stall during various driving conditions and the malfunction indicator light (MIL) was on. Bad Spark Plug, Wire, or Fuel Injector. But that Throttle Position Angle at 301. Then Tools&g