Symptom: a 2006 annual FAW - Volkswagen Jetta 1.6L sedan, equipped with BJH engine, mileage 33,000 km. According to the user to reflect, a month ago the car hot car appeared occasionally bad the car's fault, the recent hot car will start every time the car is not good, but the cold car everything is normal, that is, put a few days can smooth start the car.
Check Analysis: Because this car has been repaired in a number of repair shop, I consider in addition to the original fault is added human error. First, carry out basic checks, check the ignition high voltage and measuring the fuel pressure are normal, the use of fault diagnostic trouble code retrieval, presence mixture is too thick renault can clip diagnostic interface fault codes, start the car, the engine data stream oxygen sensor is displayed at -10 adjusted between -20%, indicating that the mixture too thick. For hot car mixture is too thick lead to bad the car's fault, there are a number of possible reasons for failure, but according to maintenance experience, common causes include timing dripping fuel injector, the cylinder too much coke and gas distribution errors, etc., the following targeted by one investigation.
Because when measuring the fuel pressure before, Paul pressure after pressure is normal, so you can exclude the possibility of leaking fuel injector. This car has been cleaned to avoid demolition, but mileage is shorter, and therefore can be excluded too much soot in the cylinder may be. Maintenance personnel observed when hot car starter, every time with the car and then turn off, so decided to check the pressure in the cylinder to build pressure stage if there are problems. Starting cylinder pressure measurement, found that when there is no cylinder pressure measuring 3-cylinder, cylinder pressure gauge will not be a problem, right? Other cylinder measuring cylinder pressure is normal, again measured the 3-cylinder cylinder pressure, cylinder pressure is normal, the highest cylinder pressure of time is normal. But I found that the results of several measurements 3-cylinder cylinder pressure are different, it seems the problem lies in the 3-cylinder.
Troubleshooting: Remove the valve cover, observe the three-valve cylinder sd connect found no problems. After removing the camshaft found the problem, three-cylinder intake valve spring break, and valve spring following more of a spring seat.
Review Summary: This car has been repaired because other repair shop, so I think this may be the spring seat maintenance staff put something before, the purpose is to change the broken valve spring telescopic length, this repair method is not desirable. Intake valve valve spring break, the impact of the valve stroke, resulting from mixing too thick, resulting in a hot car is not good with car trouble.
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