Could the exhaust back pressure be a result of shifting valve timing 1. Why such a shift in valve timing? I have known such to generate huge repair costs if owners are not aware that they need regular expensive replacement. My current vehicle Nissan patrol also has a chain driven cam. That is another possibility if you find that everything has been fitted properly and the engine light comes on again. . I was getting code 17524 for S1, B1 so I replaced the sensor on the passenger side, front.
All you need to do is take the old one off and screw on the new one. Why such a shift in valve timing? Jul 09, 2009 ive bought a cat back scorpion exhaust for my mk4 2. Why not ask yourself this same question before replacing the suspect component? These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage. That makes sense as those are the wires that carry the current for the heater circuit. So why do we need to measure the valve timing of individual cylinders when we have verified Crankshaft and Camshaft positions, zero backlash and the correct relationship between all timing gears and shafts? Continue driving and see if the check engine light turns off. We are always looking for top class Companies to join and support this website, so to get more details of our excellent value advertising packages please for full details.
Thank you for your work. This was now getting serious and expensive as the valve timing must have slipped even further for such an increase in the cylinder pressure during the exhaust stroke. As a result further diagnosis time was now required. The use of a conventional compression gauge would have missed both these events. I'm checking the wiring now. During the above tests it was noted that cranking time had increased before the engine would start accompanied with lumpy idle speed before stabilising. About a month ago I was leaving the in-law's place and the Jetta's check engine light came on and stayed on - meaning I had an engine issue.
Thank you soooo much for posting up this solution! Assumptions must never accompany diagnosis. Initially 9 degrees max at the Crankshaft to 45 degrees at the Exhaust camshaft! Maybe this is a ploy by the dealership to get make some money. Is there any way of bench testing the sensors? I got the following below. Therefore ½ a crankshaft tooth the gaps between pick-up teeth equates to 3 degrees With the camshaft running at ½ engine speed, 3 degrees of crankshaft rotation equates to 1. Using PicoScope to measure dynamic valve timing highlighted a timing chain wear issue. So you should chech it on our car models.
Like any valve timing error we all know the potential for valve damage and so it only seemed logical to momentarily run the engine and confirm the integrity of the valve gear before committing to a timing chain repair only! At last, a breakthrough in the diagnosis and something conclusive to follow. With this case study in mind, I think there is real value in dynamic valve timing checks during routine maintenance in order to obtain a timing gear signature for the engine under test. Then I found out that number 1 and 4 injector wer not working at all. Our relationship with the customer pays dividends during diagnosis where rapport is essential when things appear to go from bad to worse. The use of a conventional compression gauge would have missed both these events. With this case study in mind, I think there is real value in dynamic valve timing checks during routine maintenance in order to obtain a timing gear signature for the engine under test.
Now I'm still getting the same code. When I asked about reproducing the fault, I was wanting to try and understand what circumstances caused the shudder, as that seemed to be an engine imbalance, probably caused by a single cylinder problem. Your photo says your car is a 1999 6N, but from what I can see. Our in-cylinder pressure waveform would suggest not given we can generate over 13 bar on the compression stoke and 10 bar once again during the exhaust stroke. The engine capacity is given in cubic centimetres cc. Once in a while a mass air flow sensor will fail when replacing the air filters simply by disturbing it. You can look at measuring blocks in 014 to 028 in vagcom for further information Have you rechecked the valve timing? With the valve timing fixed, individual cylinder valve timing can be measured.
You could start the engine and remove either spark or fuel from one cylinder at a time. Could this be compression related as we seem to have exhausted all other possibilities? If you have Elsawin that should be a big help. When the check engine light comes Volkswagen Polo P1116 code on the first you should check is the gas cap. Equally when carrying out a dynamic valve timing check using Crankshaft and Camshaft signals, whilst we can measure the slightest deviation in Crankshaft and Camshaft correlation we must remain aware of the location of the Camshaft Sensors when dealing with multiple Camshaft engines. Figured I should complement this thread with some pictures of what I'm talking about.
Is t possible that they can be reversed? Also does this fault code refer to the lambda sensor before or after the cat? I'm getting engine light also and this fault code : 16519 P0135 O2 Sensor Heater Circuit - Malfunction Bank 1 Sensor 1 Must be about the same thing? Could this error be responsible for our Map sensor and fuel trim codes? Update, today I got playing with a multi meter and checking pins between ecu and connectors, didn't get far as I found the earth wires at the ecu had a high resistance and was showing ~5v so I tried to undo the nut and it snapped clean off meaning it was barely connected, so I drilled a hole and clean the metal and put a bolt through the metal and ran a new earth on the other side down to the gearbox earth point. With our vehicle above, the Camshaft sensor measures the position of the Inlet Camshaft only and not the Exhaust Camshaft! The back pressure via the O2 sensor aperture outside of the cylinder returned a value of 165. The whole process was pretty painless, that is if you don't count the couple of times I burned myself and the 10deg parking lot that I had to do the fix in. The back pressure via the O 2 sensor aperture outside of the cylinder returned a value of 165. These captured waveforms timing chain signatures can be used to monitor timing chain wear over time at each scheduled service protecting both the customer and workshop whilst presenting a potential repair opportunity. Interesting note here was the peak compression remained high at 13. Spark plugs typically need to be replaced every season or 25 hours of use.
Pin 2 carries the feed for the heater circuit from the fuel pump relay, so you should start the car with the pin disconnected and confirm 12v is present when the car is running. So why do we need to measure the valve timing of individual cylinders when we have verified Crankshaft and Camshaft positions, zero backlash and the correct relationship between all timing gears and shafts? You can then easily test the continuity to the other pins. It's funny i was helping a mate out with a Ford zetec engine which had siezed. Both have the potential to effect all cylinders equally and both could produce the symptoms described by the customer lack of power, fuel trim correction and cutting out. Our relationship with the customer pays dividends during diagnosis where rapport is essential when things appear to go from bad to worse. With the confirmation of shifting valve timing, the pressure transducer was installed into each cylinder for an overview of the effects on peak compression where all were found to be normal. And yes all the wiring and ecu etc is the correct one for the engine, I swapped everything over from a donor car.
I was lucky that I had got a Milltek recently as it was an easy job to replace according to the dealer. The compression test results below suggested compression loss and individual in-cylinder valve timing errors! This practice was officially discontinued when Australia converted to metric measurements in 1973, although both were used together for a number of years afterwards. However, the expansion pocket formed at the base of the expansion stroke confirmed the Intake and Exhaust valves to be seating correctly, therefore not deformed! As a result further diagnosis time was now required. I came up with 2 ways to fix the short, broken harness: 1 pull connector apart, lengthen wires, rebuild connector 2 remove connector, lengthen wires, permanently attach the harness. It is at this stage we should take stock and step away to ponder before we commit to our diagnosis. I went back to your first post and looked at the engine codes. Anyway, I hope this helps shed some light on the 17911 fault code.