Mass airflow engine air calculations are the simplest for me to understand. Hope you find the issue before the dealer takes your $$$$. I am waiting on the delivery of a pressure gauge so I can check the accuracy of the MAP sensor in more detail. Today I'll go for a good drive and check short term fuel trim, as I've read today that it's more important than long term. If you connect a scan tool to such a vehicle, both the short and long-term fuel trim data will be displayed as percentages. Fuel trim for diagnostics | Vehicle Service Pros. Also the weather is considerably cooler then when I last tested.
The freeze frame fuel trim data showed that the engine had been running lean when the code was set. Today it is 19 degrees C and I have a faster idle speed. EGR stuck partially open can cause issues as well. An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing. Fuel Trim: Finding a Vacuum Leak and Performance Issues Using Fuel Trim Data | Auto Service Professional. I believe that during idle, the BPV can be slightly open, so plugging it could cause the MAP to behave like it did. One last point, I think the exhaust smells rich. Cold side..... yeah well you get it. A rise in the water level of about 1½ in. Each different vehicle manufacturer will use the inputs of these sensors differently, so don't think just because the GM product you worked on yesterday calculated air mass one way that Subaru that's here today will be the same. At 2500 RPM my STFT goes back to the -11 to -4 range and my LTFT improves to 0-8 but only when I accelerate.
Tried it on the Miata, 0 to 99. Finally, remember to clear the KAM after all driveability repairs are completed. Speed-density fuel management systems uses several different sensor inputs to calculate air mass. At idle with the engine running in closed loop, the STFT and LTFT were both in the +20% area and the engine was missing, bucking and running rough to the point the SES light was flashing (although it hadn't set any misfire codes). Thank you in advance for your help and sorry if the post was confusing at all. Voltages correlated closely with the performance of the car - dropped to zero when off the throttle, aligned with eath other when on the throttle or idling. Still runs great, feel wise. Im putting this down to denser air because its approximately 15 degrees C cooler then when I last tested. Long term fuel trim high at idle engine. Faulty MAFs even from genuine manufacturers aren't unheard of though so if you're confident you've no more leaks I'll keep my fingers crossed the new one fixes the problem! Be it the brake booster line as well, even these can leak internally. The outcome of these two different fuel control systems is the same: an engine that produces good power, runs efficiently and has a clean exhaust.
9V, and at 30 mph from. As we discuss the fuel/air management systems, I would like to present a few things I have found that simplified the understanding of how they work. The PCV is in good condition and does not appear to leak. Thats where you get your +/-% for STFT. High LTFT at Idle. - ScannerDanner Forum. Even though the Envoy is struggling to stay at 60 mph, the data PIDs show nothing out of the ordinary. The Envoy, on the other hand, relies on the speed-density fuel management system. This item is critical. The computer uses both to meter air/pressure. The car did have a new timing belt before I owned it.
The diaphragm in the PCV oil separator assembly had ruptured, allowing full manifold vacuum to enter the engine (some manufactures will supply a crankcase pressure or vacuum readings for diagnostics, although GM doesn't for this vehicle). I'm with what was said above about returning the car to the shop who did the smoke test. The engine is the 4. The PCM uses input from the heated oxygen sensors (HO2S) to help maintain a stoichiometric air/fuel ratio (14. 45 represents an air/fuel mixture that is at, or close to the stoichiometric value, and signal voltages above or below this value represent either a rich, or a lean mixture. The van was parked outside overnight to allow a cold start. Long term fuel trim high at idle power. I also ran some Seafoam through the gas tank a few times. I started checking hoses by unplugging them (and manually plugging the ports), and also by spraying around the S/C and all vacuum ports and hoses with carb cleaner (carefully) to check for changes in engine revs. Could this issue be caused by a leaky intake valve? The car ran great again at idle and partial throttle, and was hitting the target AFR's in every cell. I shut off the engine and installed a fuel pressure gauge to investigate the hard start and rough running, being suspicious of a leaking fuel injector (the STFT was a clue to this as well indicating rich). 1 is a 2001 Ford Ranger powered by a 4. Porsche specified plugs (14FGR 6KQU) and generally recommended to be the ones to use. Less air means less fuel; less fuel means lean.
Fuel trim diagnostics. I've been reading the service manual for my car and researching these separate issues on other corners of the internet, but I can't find anything that refers to this peculiar set if circumstances. Don't have the AC running while you do this. Not Allowed: to create new topic. Also the MAF shown at idle (~4. I'm not sure what it is, but I think it's either clogged fuel injectors or a vacuum leak somewhere. Apologies, I can't get them to load in order. During normal operation of the vehicle, and provided the oxygen sensor is in closed loop operation, the ECU will react to changes in the composition of the exhaust stream almost instantly, hence the term, "short term fuel trim", and it will do so several times per second. Since this is already a really long post.... Made a smoke machine and found a significant leak caused by a missing O-ring on the brake booster vacuum take off. I can't find any leaks anywhere. But I brought it to the mechanic, they did a proper smoke test with UV dye and found a leak in the intake manifold gasket on the driver's side (it was the FHI upper o-ring). Long term fuel trim high at idle air. Same exact tune file as what was datalogged in "", but reloaded within a few minutes after I finished logging the "" file. Then I started searching for air leaks.
Out-of-range LOAD values are often MAF sensor-related. I checked the exhaust for leaks and found the manifold leaks. Still full after 1000 miles) plus some Lucas Oil Stabilizer. And check the cam deviation reading (only on bank 1 on an early car). Note also that fuel trim values should only be taken when the engine had been running at the above speeds for at least 30 seconds.
This is not for your issue just an FYI. The fuel pressure check indicated a slow decay in residual fuel pressure and again this was another clue. With a simple vacuum gauge you'll be able to compare its readings to the map sensor. The MAP is manifold absolute pressure, the MAF is mass air flow. What if you don't have a vacuum leak? Hold that thought while we delve into the theory of fuel management.
3) Check your answers to your class work-- "6-3 Practice Ws21-- Elimination Using Addition and Subtraction Answer Key" or "6-4 Skills Practice Ws26-- Elimination Using Multiplication Answer Key". If you haven't already done so, complete columns a and b. You will receive NO CREDIT for the assignment(s) handed written on loose-leaf paper. ) Due Tuesday, March 11th at the beginning of the class period. 6-3 skills practice elimination using addition and subtraction games. Answer at least five problems on each page of the Proportions - Percent Packet Worksheet. Complete six "GuidePractice" problems 1, 2, and 3 on loose-leaf paper (collectable). Copy KeyConcept box into your notes. Don't do the "Mixed Practice". Copy of the "KeyConcept" box. Begin to review the lessons and the IXL practice assignments referred to in the T3 Midterm Study Guide.
For those who only went through the "Add and Subtract Polynomial" mini-lesson today, complete 8-1 Skills Practice 7, #1 - 24. 0 points => No notebook and/or less than 50% of the current notes. Complete Systems of Equations Review 2 Ws, #11 - 21. See "6-1 Study Guide and Intervention Ws5 and Ws6 Answer Keys" found at the bottom of this page.
Wednesday, April 30th: 1. Friday, April 25th: 1. Extra Credit Assignments. Tuesday, April 22nd: 1. Come tomorrow to prepared to review the packets and to ask any questions that you may have come up with. Hand in the IXL worksheet.
Wednesday, May 7th: 1. Complete Solving Linear Systems Using Addition Ws73 (handed out in class, and pdf may be found at the bottom of this page). 2) Complete 6-4 Practice Ws27, #1 - 14 (Elimination Using Multiplication). Complete 20 problems and target 80 smart points, for a total score of 100. 6-3 skills practice elimination using addition and subtraction. Find the Answer documents for each of the above review packets at the bottom of this page. Review the PersonalTutors for Lesson 6-4. The content of your notebook for this week should include: I. Complete 8-3 Practice Ws21, #1 - 20. SHOW YOUR WORK or Explain Your Answer for credit.
Monday, April 21st: 1. You much show your work for full credit. Handed out in class, also found at the bottom of this page). Due Thursday, March 13th by 7:30 a. m. Monday, March 10th: (1) Complete Lesson 6-1 preview exercises. 2) Prepare your notebook for a Notebook Check on Monday. Only those assignments completed directly on the worksheet(s) will be considered for extra credit.
Due Friday, March 14th by 7:30 a. m. Wednesday, March 12th: Complete IXL J > Y. Friday, April 4th (Spring-Break Assignments): Required Assignments. Monday, May 12th: 1. Monday, March 31st: Group 1: Complete 6-4 Study Guide and Intervention Ws24, #1 - 12 (skip #4), and the attached 6-4 Skills Practice, #1 - 6. 6-3 skills practice elimination using addition and subtraction answers. Complete 8-1 Practice Ws8, #1 - 20: Adding and Subtracting Polynomials. Thursday, March 13th: (1) Complete the Take-home Quiz: Solving Systems of Equations by Graphing". Monday, March 24th: Complete problems #1 - 10 of 6-3 Study Guide and Intervention Ws18: Elimination Using Addition-Subtraction. Complete problems #21 - 26 as bonus questions. Due before the beginning of class tomorrow, March 27th. Thursday, April 3rd: (1) Study for tomorrow's quiz: Solve Systems of Equations Word Problems. Thursday, March 27th: Prepare for tomorrow's quiz: Solving Systems of Equations Using the Elimination Method (Addition and Subtraction). Friday, March 21st: (1) Study for Monday's quiz: Solve Systems of Equations Using the Substitution Method.
Copy and define the "NewVocabulary" terms in your notes. Watch the "Personal Tutor" for each example #1, 2, and 3; and do the related problems. Bonus problems #19 - 22. Review the Personal Tutor for Lesson 6-1, Examples 1 and 2. Each worksheet may be found at the bottom of this page. Finish 20 problems for a target score of 80.
2) A Tale of Two Truckers (60 Extra Credit points). Read the Lesson 6-1, pp. Completer 10 additional problems on, J > Y. Check your answer on the answer document provided below. Each or either of the two above assignments may be completed for classwork extra credit. No need of the IXL worksheet. Complete 8-3 Skills Practice Ws20, #1 - 18 (both odd and even problems). 11 Solving System of Equations by Elimination: Word Problems (10 Points). 3 points => Less than complete but more than 50% of notes organized in a notebook. 2) Assess your accuracy on the classwork assignment from Monday and Tuesday. Begin the odd-number problems of Write an Equation of a Line Kelly Ws74 - 75 (pdf may be found at the bottom of this page). Begin to work through the Solving Systems of Equations review packet handed out in class. Thursday, March 20th: Complete J > Y. Tuesday, March 25th: Complete the worksheet handed out in class today.
You must print the work sheet and complete the work on the printed worksheet. Tuesday, May 13th: 1. The sum of the two, up to 100, are your point value. Tuesday, May 27th, through Friday, May 30th: Complete IXL K>V1 - V9.