causing a positive fuel trim. The percentage reading represents the difference either above or below the anticipated amount. The range of authority for Long Term FT is from -35% to +35%. 0 %. If the power steering fluid level in your Escort is low, fill it up to the maximum. 1 above shows the fuel trimAs the throttle is opened, the engine speed increases and the engine load increases while the long-term fuel trim has taken a big dive. The fuel trim Parameter Identifiers (PIDs) on the scan tool are telling you how the ECM is adjusting the fuel injector’s “on time” (pulse width) in order to add the correct. 34 % Long Term Fuel Trim - Bank 2 0. But yet they have different rated fuel pressures. The Fuel Learn is saved in the computer’s memory, and can only be cleared by setting the “Reset Fuel Learn” to 1, and then turning. Note that actual support will vary by vehicle year and model - you can check what datapoints your vehicle will support by using the Compatibility Tool. 5 seems normal to me. Be scared of anything above 10% or below -10%. Sent the first scanner back & received a another scanner today. 375. This graph shows a fuel trim voltage drop-out caused by a faulty mass air flow sensor. When the engine is first started, it begins to warm up to its regular operating temperature. 2. To bring the. my situation is the opposite. 6, short term fuel trim B1 +7. 0% and 10. is the cause of the lean condition, then fixing it will restore fuel trims. It does the same thing as the first one. The opposite happens when the o2 sensor sends a rich mixture signal to the PCM. The fuel pressure was checked with the engine running. The #1 fuel trim values do hover around 0. The effects of a stuck-open EGR are problematical because, on the one hand, chemically inert exhaust gas dilutes the air and fuel in the. A restrictive air filter may not set a code, but the restriction and compromised fuel trim will hurt the power and efficiency. The Fuel Trim strategy is expressed in percentages. Long-term fuel trim averages several of the short-term readings to affect the fuel base mapping. Fuel Trim Data Storage To enable the correct air/fuel ratio, (stoichiometry = 14. -5. Pressing the throttle a little bit more and at higher MAP I get -4% to -8%. Anything over 10 will indicate that a leak is present. Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST. The fuel trim system is at the rich correction limit. Or I would be really lean. 7:1 A/F. 6 %. Long term fuel trim is an important aspect of engine performance, which determines how much fuel is required to maintain optimal performance. The percentage reading represents the difference either above or below the anticipated amount. 3 for bank 1. Arriving in spring 1997, as an early ’98 model, was a sporty Escort ZX2 coupe. 0 is equal to 14. 2%. 01 ASP IS300 14 Cadillac CTS-V 07 C6 Z06 97. LTFT B1. The best condition is when that the short term fuel trim is oscilating between -3% and 3%. 25 while the RKAT trims went to approximately -0. A -20 percent short term fuel trim indicates that fuel had to be removed by shortening the injector pulse width to achieve the proper air-fuel mixture. There are two types of fuel trim – short term (STFT) and long term (LTFT). 0 (totaled) 3 inch lift. The KOEO fuel pressure of 24 psi is below the 35-38 psi normal range & the KOER fuel pressure of 28-30 psi is on the low end of the acceptable range. FORD MOTOR COMPANY 1985 – 00 Ford, Lincoln, Mercury, Merkur including FWD vans Carbureted Engine Year Pressure @ idle (PSI) 1. Long/short term fuel trim is basically the adaptations the car has set. If there was a real air leak both readings should be positive. ( Tired of going to the dealer for 150. 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). The purpose of. Typical values range between ±7%. of air to 1 lb. There are a few different conditions required for the engine to run closed loop mainly the coolant temperature and the O2 sensor becoming active. 3 on bank 2. Check the EGR valve. net!. The passenger bank LTFT reads steady at . When at around 25% throttle and 50kpa MAP LT fuel trim is just -1%. 00 a pop to scan. The STFT was at +22% and the LTFT at +20%, and these trims were occurring at idle on a warmed-up engine. If total fuel trim is greater than plus 10%, the PCM thinks the air/fuel ratio is too lean and will add fuel to bring short trim values to the correct range. 0 is a typo and should be -7. Was -20 to -25 (idle) LTFT 0 to -2. 2403 posts · Joined 2016. But, in general, you want fuel trim values under 10%. STFT is an immediate response to the air/fuel mix. The intent here is simply to describe the help I am seeking in a more concise manner. Things like EVAP purge and DFCO can temporarily mess with the values, and have their own trim cell. The percentage reading represents the difference either above or below the anticipated amount. This could be high fuel pressure. Check the Fuel Trim PIDs, if they close are to zero, less than 10, then the system is doing little to correct fuel mixture. Most of them were misfire codes, and now both 02 NEW sensors were being shown as failing. Fuel control driveability complaints and the various issues that accompany them are a frequent concern in most repair shops. Elevate engine RPM to around 2000 to 25o0 RPM in park and record the fuel trim numbers. Need to find the cause of the excessive fuel. STFT is going to immediately react to a situation by adding or deleting enough fuel to correct the condition. > The car is ford escort 1991 1. 8 g/s. Any fuel trim reading greater than 5% indicates a problem that requires checking cylinder balance, and/or checking with a 5-gas analyzer. Under normal conditions, actual atmospheric pressure or air pressure is usually around 14. 6L. During•171, 172, 173 (HO2S11 lack of switching, Bank Always verify the STFT (short-term fuel trim) and the LTFT (long-term fuel trim) while reading live data from the OBDII scan tool. 9 volts. Either the engine is taking away fuel or adding fuel so. 9V at idle. I cannot get any short or long term fuel trim correction readings. Autozone has a GP/Sorenson FPR PN 800-302 listed for the 2000 PAU and 2005 PAU. My vehicle (Ford Fiesta 2014 Petrol) always have a positive long term fuel trim, which means its running lean mostly. . You will find a leak or a faulty one-way valve that is causing the P0171 code in most cases. Tech B says that when the air-fuel ratio is at 14. The last picture below is a picture of The fuel pump inertia switch for a Ford Escort its attractive, gently curved dashboard bears a strong ford family webfeb 11, volkswagen calls fuel trim oxygen sensor adaptation, and ford classifies fuel trim as a continuous monitor that runs when the fuel control system is in. Check the fuel pressure. com. If it is too low, check the fuel filter, fuel pump, fuel pressure, and regulator. Codes 171 and 174 indicate a lean condition for banks 1 or 2. Most common is 32. Speed of the vehicle Technician. It will typically flow better than a clean filter. Too low fuel pressure can cause the engine to run lean, causing the O2 sensor to read low voltage as described in step 3. For lowest emissions, the engine computer tries to keep the fuel mixture balanced around 14. 8% , but there is some variance from about 30% - 55% . 6 CVH EFI engine) > > dunno what to do. Reporting 99. I replaced the coolant temp sensor, and checked O2 sensors. All of which I have surge and fuel trim issues. Codes 172 and 175 indicate a rich condition in either bank 1 or bank 2. I replaced the O2 sensor downstream of the - Answered by a verified Subaru Mechanic. Runs pretty smooth at 2500. Black smoke from the exhaust. P0170 Fuel Trim Malfunction (Bank 1), P0410 Secondary Air Injection System, Car will not start just turns over, seems like it is not getting fuel. This is known as "Stoichiometric", a. Really, the oxygen sensors are what drive the fuel trim readings. A restricted exhaust on one side of a dual exhaust system can cause an imbalance of fuel trim between banks. Code P0173 is triggered by the engine control module (ECM) when it detects that the air-fuel ratio is too lean or too rich. Fuel Trim is the ECM/PCM’s fuel mixture adjustment indicator that is visible on a scan tool live data feed. 14% is a bit high. measurements that express fuel trim when viewed on a scan tool. 3. Coachella Valley. Faulty oxygen sensor. I checked & all the readings checked correct except for vref voltage (5 volts) on PCM pin 90 key on. However it is not perfect. 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. I have just installed 2 new O2 sensors and the Fuel Trim % for the B1S2 sensor is still pegged at 99. It does the same thing as the first one. Short Term Fuel Trim. You will find a leak or a faulty one-way valve that is causing the P0171 code in most cases. The 97 bwill give short and. For lowest emissions, the engine computer tries to keep the fuel mixture balanced around 14. Fuel trim analysis & MAF testing | Vehicle Service Pros Diagnostics and Driveability My first encounter with fuel trim information was the GM block learn and integrator. Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST. 42. 4 4x4 TRD ( <3), '06 Taco Prerunner 4. Much later, when I got back home, the idle timing was -24 degrees, but the driving timing was still usually -33. To do a "hard reset", pull the negative side battery terminal and leave it off for 30. Googling leads me to believe those MAF readings are not within spec but those are based off a Pilot and an Odessy. It would be a positive fuel trim to add enough for the one not firing. If the message ok’s, the software is ready to use!Original sensor typically shows some positive long term trim values. Oct 20, 2021. Vacuum leaks – PCV hoses, vacuum hoses, intake manifold gasket. Codes 170 and 173 indicate an issue with the fuel trim for which the ECM can no longer compensate. PLEASE CLARIFY FOR ME - You re-installed everything, then pulled each spark plug "one at a time" checking the compression (with a compression test "dial. All you need is a multimeter. 7. When I looked at the freeze frame data for p1443 the fuel trim showed different than -100. At idle driver side STFT and LTFT readings are also consistently higher by about 4% average. With negative fuel trims the pcm thinks there is a lean condition and is adding fuel to correct. Check fuel trims on your scan tool. Engine Coolant Temperature 163 °F. Read FAQ. 7lbs of air. On newer models a faulty fuel pump or fuel pump driver module 6. Fuel pressure regulator. However, if the amount of compensation is too much, a P0173 code may set. Poor engine performance. 12/28/2011 UPDATE: While looking for vacuum leaks, discovered that the CCV return hose had an area worn through from the alternator wiring harness (post #53) 01/06/2012 UPDATE: Problem closed. This statement belies experience. If LTFT is 12% and STFT is negative 6%, total fuel trim is 6%. 7 to 1 (14. Ideally, all Fuel. /. Plug the cable into the car and to the laptop and turn the ignition on. mcgowaw said: 2 banks = 2 short and 2 long term fuel trims. 05 or +5%) means that the fuel injector pulsewidth is being lengthened by 5% in order to maintain target AFR. LEAN DTCS: In general, a + 25% or greater fuel trim correction will store P0171/P0174 DTCs. Actually, I can probably find a compliant mechanic, but the engine is still. Updated: July 10, 2021. Connect a fuel pressure gauge to the fuel rail and make sure that the fuel pressure is correct. A -20 percent short term fuel. P2098-DOWNSTREAM FUEL TRIM SYSTEM 2 LEAN (CONTINUED) For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS). If fuel trims are offset, or go from a negative fuel trim at idle to positive fuel trim at high RPM / under load, it can be MAF. 10. At -25 or higher the PCM is maxed at how much it can correct the mixture and you will get a code po172,po175 rich bank 1 and rich bank 2. 3. Fuel trim should be checked at idle, at 1,500 rpm and at 2,500 rpm. A short term fuel trim (integrator) reading of 118-138 is considered normal. On my 2001 Southwind, I have installed a Scan Gauge III and I am greatly puzzled by the readings I get for Long Term Fuel Trims. 7 to one (say 12 to 1), the fuel mixture is RICH. August 31, 2010. I have just installed 2 new O2 sensors and the Fuel Trim % for the B1S2 sensor is still pegged at 99. The car will always shoot for ~14.