Our professionals are here to help make sure you find the answers you need to. The P0170 code means that the powertrain control module is detecting a fuel trim that is outside the range of specification set by the vehicle’s manufacturer. The fuel trim system is what your Chevy Equinox uses to adjust the air-fuel ratio for optimum combustion. . . Long Term FT is also referred to as Fuel Trim. 7L Power Stroke Fuel Injector Puller. Fuel control driveability complaints and the various issues that accompany them are a frequent concern in most repair shops. Gaudai Sándor. EGR or EGR valve. Youre right about the WOT log, doesnt help since you are running meth on OTS map. Block Learn = LTFT Integrator = STFT The measurement values are now expressed as a percentage when viewed on your scanner. I also found when I disconnected the front Bank 2 O2 sensor and increased RPM past 2500 rpm, STFT voltage and fuel trim readings on Bank 2 start fluctuating at low levels. The percentage reading represents the difference either above or below the anticipated amount. (2) Throt. I am trying to resolve an idle, stumble, very slight miss issue-most noticable at idle speed. 4 coulda swore he had worse issues. – Check the fuel system. We will be putting up an article on fuel trim soon but this is a huge topic all on its own. 216 1 Sep 29, 2012 desplaines, Illinois. A vacuum leak would give you + fuel trim readings. The fuel trim system is at the rich correction limit. I also religiously use BG 44K once and sometimes twice a year. will 'learn' the correct fuel trim for the pressure, as long as it is within the adjustment range. A normal long-term fuel trim reading will appear to stay the same, giving a. Just. Fuel trim is an essential indicating metric that can shed tons of light on how hard the engine controller is working to achieve its desired air-to-fuel ratio otherwise. For example, a car with a 0-60 mph time of 4. My scanner shows + 10 to 14% Long term Fuel Trims at 1750 RPM and cruising at 65 mph. So from what I read about. The percentage reading. ² When Monitored: With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude. The appeal of the Escort, particularly the ZX2 Sport, is its affordability. When driving, the value went up, but not by much. Engine seems to run totally fine. 97 would indicate an air/fuel ratio of 14. Proven Member. ” Though it shared the regular Escort’s chassis, the ZX2 had unique exterior and interior styling, and sportier suspension. Your OBD-II Trouble Codes Repair Site. A negative fuel trim percentage indicates a taking away of fuel while a positive percentage indicates an adding of fuel. 0L engine. OBD-II Trouble Code Chart. a little lean. A normal long term fuel trim reading will appear to stay the same, giving a long term average of fuel added. 50 lb/hr and injection pressure of 39. Then perform a fuel volume test to rule out the fuel pump and fuel pressure regulator. Indeed, the O2 sensors are constantly changing values, as they should. 2 NORMAL READING DURING RAPID ACCELERATION AND. The fuel system is operating within specifications. Not sure what you mean by specs. Likes: 0. The O2 % reading you are seeing sounds like it is reading in Lambda, it behaves similar to fuel trim readings. I have read most of the threads in this forum concerning fuel trims for the 8. 0 >> Haynes #686 (escort up to 1990) says 2. My 97 ford escort has stopped working after an oil change. If there are no issues and no check engine light, here are your options: #1 You a viewing downstream trim numbers that are not valid on your vehicle. 4. tech b says percentage is used. Instead of using a range of 0 to 255, the range is now 0 to -100% and 0 to +100% Percentage Chart Fuel trim is a program in the ECM designed to compensate for these changes. Point of clarification on the fuel trim values: In my OBD-II reader app, the values are shown as follows: Fuel trim bank 1 sensor 1 = FT 1x1. When viewing Short Term Fuel Trim, you should see your data reading shifting rapidly between rich and lean. Wide open throttle is fuel enrichment mode and it is normal to see 12:1. Empty float height and float retention matches OE specifications and guarantees correct gas. Positive means it's adding fuel relative to baseline, and negative means it's reducing fuel. In other words the engine-control computer is constantly reading the o2 sensor (s), the maf, and the ECT and it feels those readings should be self-consistent with each other. 2403 posts · Joined 2016. This is classic fuel trim behavior when a vacuum leak is present. C7. Scott Brown. When at around 25% throttle and 50kpa MAP LT fuel trim is just -1%. When the sum of the ST and LT trim exceeds ~+30% the PCM throws the P0171/174 DTC, which means the PCM is adding a lot of extra fuel and the O2 sensor is still seeing oxygen, hence the lean DTC codes. If the O2 sensors are fouled, the catalytic converter (s) could also be in line for replacement. Keep adding propane until the short term fuel trim is over -20%. 2. 7 units of air to 1. If the fuel trim runs into a problem that forces the PCM to log a P0170 code, the following symptoms may appear: An illuminated or blinking Check Engine Light; The vehicle’s fuel mileage drops because of wasted fuel; The engine suffers from hesitation when the vehicle acceleratesHowever it is not perfect. There is still a lot of power lacking near idle rpm. 2. As soon as it recovers, the truck runs fine. Are you faced with a customer’s vehicle performance concern? Or a. ) The PCM maintains multiple fuel trim tables that are load and rpm dependent. In this case, STFT carried a greater weight than LTFT. Just because the fuel trims are saying it is making a correction for a rich running engine does not mean that the engine. LX Wagon 4D. Use the information to target the next di-agnostic steps. Wed Feb 01 17:05:22 EST 2017 RecordID Fuel Trim Bank 1 Long Term(%) Fuel Trim Bank 2 Long Term(%) Fuel Trim Bank 1 Short Term(%) Fuel Trim Bank 2 Short Term(%) Air Fuel Ratio(Measured)(:1) Intake Air Temperature(°F) Intake Manifold Pressure(psi) Mass Air Flow Rate(cfm) Miles Per Gallon(Instant)(mpg) O2 Volts Bank 1 sensor 2(V) O2 Volts. From what I understand this is the dme taking away fuel because of the mixture being too rich. g. Stove and rich negative term fuel trim of course, but it connect to constantly compare cars, the shop with the car. I'm throwing P0171 and P0174 codes on my 67 Camaro with an LS2/T56. If it returns, my guess is the MAF. I installed new FI HFC and TDX the first week in Nov. 00 is stoichiometric or 0%. Escort 14 CFI. Monitor and record the fuel. Any positive fuel trim readings indicate the PCM is adding fuel to compensate for a lean condition, a negative reading means the. /. And IIRC it's +- 35 when you add them together together and shouldn't trigger a light. All sensors share the same signal return though. 75 is the difference between the air to fuel mixture. V6 and V8 engines have two sets of both fuel trim PIDs, one for each side (bank) of the engine. What makes checking this so easy, is that the PCM will let us know how Lean or Rich the Air/Fuel Mixture is with its Long Term Fuel Trim values (for bank 1 and bank 2). The fuel gage circuit consists of the sending unit in the fuel tank, the gauge in the dash, and the wiring and dash wiring (or circuit board) between them. I bought a 2002 Ford Focus ZTW (Zetec, at 100k miles) a month ago, and I noticed OBD2 always reads LTFT for both bank 1 and 2 reading pretty high at 10-25%. 8 %. 97 by 14. 5 in. The Mass Air Flow sensor (MAF) is one of the key components of an electronic fuel injection system in your car. com,my name is ** get started solving your problem!My experiences have had me replace the mass air flow sensor,with your fuel trim reading at peak level it sounds like the ecm is compensating quite a bit,I would expect the car to be running a little worse then described,this part is very expensive from the. If the voltage is OK but the fuel pressure drops, replace the fuel pump and recheck operation. Operate the vehicle at idle in park and record the fuel trim numbers. When giving it some pedal (2000 rpm+) for taking off or climbing a hill they climb to 18 to 22% until i back out. The fault codes say you have either an air leak or a bad MAF. In modern cars, an intake air temperature or IAT. Between 1500-2500 RPM, LTFTs shoot to -10 to -15%, while STFTs jump between +/- 10% wildly. Much later, when I got back home, the idle timing was -24 degrees, but the driving timing was still usually -33. The other way to test for leaking fuel injectors is to perform a leakdown test. Changes in o2 sensor voltages cause a direct change in fuel. As with LTFT, the number should usually be plus or minus five. #3. compares it to the outside air. Bank 1 vs Bank 2 indicates the side of the. As your vehicle runs, the sending unit is constantly monitoring the level of fuel in the tank. Notice that in this example, the sensor is responding to the PCM’s constant short fuel trim adjustments by switching rapidly. (too much fuel. Verify that the voltage maintains or increases under load. The Fuel Trim strategy is expressed in percentages. However, if the margin of compensation is too large, then a P0172 code will likely set. Technician B says that wide-band sensors take considerably longer to warm up as compared to traditional oxygen sensors. Fuel Trim Readings? Let me give some history with what I have done and some of the readings I have gotten. Now when the STFT is steady at 27%, the LTFT will increase to 27% to adjust the fuel delivery for a longer period. Drives: 2012 370 Nismo. Any fuel trim reading greater than 5% indicates a problem that requires checking cylinder balance, and/or checking with a 5-gas analyzer. 7 PSI (29. 2%: Long Term Fuel Trim: Similar to short term trim, long term fuel trim reacts less readily to sudden changes and represents the 'learned' behaviour of the vehicle over a longer period. Problem description: Starts and idles fine, but stumbles for about 5-10 seconds after I give it gas. Keep Reading. Postby Ludeaem » Sun Nov 07, 2021 4:35 pm. ”. $13,630. Note the idle readings, taken at 875 seconds (the green cursor): Calculated Load 40% MAP 11. 8 that they should have. 2% ranging between 2. Detailed specs and features for the Used 1997 Ford Escort Wagon including dimensions, horsepower, engine, capacity, fuel economy, transmission, engine type, cylinders, drivetrain and more. *TT. The freeze frame fuel trim data showed that the engine had been running lean when the code was set. what I found doesn't quite make sense to me. Fuel Trim Data: A Powerful Diagnostic Tool 2. So if you had a LTFT correction of 10% it would be adding 10% fuel when the boost is between ~10-12 psi (3. With a multimeter, this will be averaged, but it should stay within 0. A normal reading for an oxygen sensor will fluctuate sinusodially between 900 millivolts (rich condition) and 100 millivolts (lean condition). Note: If a fuel injector or fuel pressure regulator is replaced, do a PCM Reset and then drive the vehicle through the Fuel System Monitor drive pattern to reset the Fuel Control table in the PCM. . All negative fuel trims 1997 4. 2272 posts · Joined 2002. Long/short term fuel trim is basically the adaptations the car has set. Values normally range. Less power. You will find a leak or a faulty one-way valve that is causing the P0171 code in most cases. I bought an Actron scanner. 01 ASP IS300 14 Cadillac CTS-V 07 C6 Z06 97 Supra tt 6 speed Forced Induction Facts *READ THEM*. Anyway, a voltage closer to one volt indicates a rich condition and closer to zero indicates lean. The fact that one fuel trim is higher than the other means that Bank 2 would be running leaner than Bank 1 if the long term fuel trims weren't being used to add 3% extra fuel. what I found doesn't quite make sense to me. 6L Post by maxOverdirve » Thu Jun 01, 2017 9:34 pm A couple of weeks ago I check my truck with an OBD2 reader noticing that it lost some power and a lot of mpg. Lexus is currently somewhere between 4 and 7. High fuel trim reading usually indicates a vacuum leak or low fuel pressure. Age: 58. MAF reads only along the centerline and is calibrated assuming a consistent flow pattern, though the duct length is too short for a developed flow pattern. Look at the bank with the more negative correction for the cause. 5 g/s at idle and goes up to 200 maximum when wot at high speeds. The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. Analyze the col-lected data. Join Date: Mar 2013. Thinking the fuel savings alone over about a month might justify any expense needed to solve this problem. When the hesitation hit, it dropped to -20, -12, even as low as -4 degrees, only to instantly go back to -33 when the hesitation stopped. Turn the key to the "Off" position and then back to the "On" position to confirm the reset was successful. If fuel trim is below -10%, the engine is typically considered to be running rich. As the throttle is opened, the engine speed increases and the engine load increases while the long-term fuel trim has taken a big dive. 97 ford escort fuel pump is staying on when key turned off if you turn key back on and off again it stops and some times the fan stays on as well all so the battery is draining after 2 days when just. 0%. 55v. Faulty oxygen sensor. With the exception of the Lexus, LTFT remains steady around zero. I cannot get any short or long term fuel trim correction readings. The direct successor of the Ford Pinto, the Escort also largely overtook the role of the European-imported Ford Fiesta as the smallest vehicle in the Ford model line in North America. Haynes "Ford Escort & Orion (Sept 90 - 97)" says 3. I did a fuel system cleaning service through the mechanic a few months ago, as well as changed the distributor, both o2 sensors, cleaned the air filter, replaced the map, and got a new TB. Nothing about the vehicles fuel control is actually getting trimmed to 99% (in the case of B1S2), and the data you see doesn't reflect anything about O2 performance. I currently run 10% ethanol gasoline in my Wrangler, RX350, and Land Cruiser. ^^ This. All you need is a multimeter. P0171 - OBD-II Trouble Code Fuel System Too Lean (Bank 1) Get back on the road. 5 and 0. IDL FTRIM2 refers to driver (left) side bank. stays around +/- 5 on both ST and LT. Connect a scan tool and verify the engine has a lean fuel condition by looking at the LTFT value. 12 % SAE 0x07 Long term fuel % trim - Bank 1 -7. , a vehicle is being diagnosed with a low fuel pressure problem. STFT = Short term fuel trim, is adjusted by the pcm to overcome small problems that may arise and usually keeps the engine running as close to stoic as possible, if it stays high the pcm will kick in LTFT to try and compensate and. Search. Baselining the fuel trim data is a simple four-step diagnostic process: 1. Thanks for the diagram. Detailed specs and features for the Used 1997 Ford Escort including dimensions, horsepower, engine, capacity, fuel economy, transmission, engine type, cylinders, drivetrain and more. . Always verify the STFT (short-term fuel trim) and the LTFT (long-term fuel trim) while reading live data from the OBDII scan tool. Confirmed Fix The 20% max number is just that - the max that can be applied to long term fuel trim. 95 or -5%) means that the fuel injector pulsewidth is being shortened by 5% with respect to what the value should be based on sensor inputs to maintain the target AFR. It may be adding fuel for no reason (causing an actual rich condition) this could have a negative affect on fuel mileage. Keep in mind that ltft's are just averages of your short term trims so get your short term in line across the fuel trim cells & your long term trims will follow.