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Found 3 results

  1. When I talking about misfire some days ago, got a comment saying that she had misfire before and it turned out to be sensor issue. Then it occurs to me that there is an occasion that sensors are working fine, the actual problem is AFR inappropriate. The syndrome of this problem could be car shaking/trembling, idle speed goes too high and too low, even misfire. So I use my Topdon Artipad to scan the DTC, and got P0171. There are many possible reason for this code, you can google it, but I will summarize the essence is too much air too little fuel. When AFR is incorrect, it actually means fuel is less and air too much, the essence is too much O2 in emission. For fuel system, when air intake is fixed, the AFR will be incorrect if fuel intake is low due to component issue. For exhaust system, when air intake is fixed, air leak, O2 sensor and AFR sensor detect and exhaust system related EGR should also be considered. For the intake system, when air intake is fixed, sensor features change, leads to fuel intake less than normal. For ignition system, when air intake is fixed, what’s the reason? Think about it, when misfire, mixed gas not completed burnt, O2 sensor or AFR sensor detect too much O2 in exhaust pipe. Some inexperienced technicians might think O2 sensor and AFR sensor broken that cause this problem. But I think the exact opposite, the sensors are working just fine. P0171 and P0172 are generated because they are monitoring, but, if you don’t fix the issue asap, sensors will be dead after a while. For my last article on misfire, you can click to my profile or search "my shallow analysis on engine misfire".
  2. Two weeks ago, I have a 2011 Ford Fiesta SE with 73,000 miles. I just bought it. (The budget of a school teacher). ***The problem: The engine idles very fast at all rpms. At 40 mph the rpm is about 2000 to 2500. At 70 mph, the rpm is around 2500 to 3000. I drove it once up to 80 mph and the rpm was over 3000. Gas mileage is still an average of 30 mpg. The engine sounds very loud and sounds like it is really working hard to get to 70 and stay at 70 especially when I have turned on the cruise control. The loudness of the engine does not sound like the muffler or cat because there is no sputtering. It just sounds like it is working very hard to do the higher speeds. the loudness is annoying but if it is working fine, then I don't care. However, if the idle speed is incorrect and that is symptom of a larger problem, I need to address it. **Overview of what is fixed and what needs to be addressed: Everything works. The body is fine. Nothing leaking. I will replace the lower control arms. I am having the spark plug and "wires" replaced next week. I will put in fuel injection cleaner. I had the oil changed to full synthetic, new radiator fluid. Any suggestins?????
  3. llo what happend was that i got stuck in some snow but was able to drive out about 1 min later she died got it started then died again... it will start some times but will die right away wont stay idleing plz help.....other note the air filter cap was open and some snow got in it have replaced the filter anyway i get these codes p1354 fuel quantity adjuster position sensor malfunction modulating piston displacment sensor circuit p1562 fuel quantity adjuster upper stop limit achieved
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