Tech Mate

Ok. So I got them to check and clean the crank position sensor today. It seemed that it was in a very good state yet it didn't help resolving the issue. I also asked them to check for any issues with torque converter and I will update once I get it done. One unrelated question - just out of curiosity, is it possible that I use full/ semi synthetic oil for this engine, given the mileage being around 85,000KM? Are there long term benefits/ issues of using it? If so, which is the best - fully/ semi-synthetic?

Also, just a thought, apart from the MAF sensor, shouldn't the knock sensor detect the knock and send a feedback to ECU to retard timing?

Yes, the MAF sensor was cleaned using a contact cleaner which made no difference...

I don't get this issue while the engine is running cold; always happens once it reaches running temp. And yes, they did inspect the rubber seal 'o-ring' in injectors and said they were ok. I am sorry, I think I wasn't very specific about the exact time this issue happens; this happens just right after a gear is shifted, mostly felt when shifted from 2nd to 3rd, specifically at low RPMs. If I drive with higher throttle, this does not come up. Though nothing changes with A/C off, I have a hunch that this basically happens at a point when the engine feels more load as it is relatively easier to produce this noise on an uphill drive. Also, isn't it that an engine feel more load at lower RPMs? I did not specifically check for the gearbox yet I got them to inspect and clean the gear oil strainer along with refilling new gear oil. I feel this noise comes out from the driver's side and not from the side or gearbox. Also, I do not get get a gear jerk, at least not to a level I feel it needs attention. I must also say that it is the mechanics who confirms it is a pinging noise (even the Toyota folks) yet the noise is more or less closer to a rattling noise. I repeatedly asked them if it could also be possible that it is NOT pinging and something else, yet they were firm on their theories. Since now the torque converter in picture, I will get that checked as well. Thanks!

Yes, I do run in to a lot of traffic, yet I usually do oil changes when I reach around 2500 KM mark and I have never overrun it. But I doubt if previous ownership was attentive to it in such a way... Here are the answers to your questions: 1. Do you know the type of spark plug in use now? Was it changed during the last tune up? Yes, I got them changed. They are regular Toyota (Denso) plugs (K16-RU11) 2. Do you use Octane 92 or 95? I have been using 95 ever since I bought it, but I know for sure that the previous owner did not. I have also replaced the fuel filter. 3. When the tune up was done did they change or inspect for cracks on the injector seals? They inspected injectors and cleaned them up through some machine. No sure if they inspected particularly for cracks, but I remember them looking at each injector through a magnifier 4. Do you get this knock with AC off too? Any noticeable difference with ad without AC? It happens the same way with or without A/C. No significant difference. 5. Does your engine sound like a tractor (no offence ha!) when on idle? Yes, but slightly. I've read about the tractor noise so I do have an idea of how it sounds. Not sure if this is related or not; when I checked if timing chain was ok, I felt that it was a not tight enough. But the mechanic said it is normal and that the adjuster would automatically tighten it up when running. By the way, maybe I should change my mechanic as I don't think properly understand a lot things; to be honest, until I mentioned to them about the OCV filter (and I also had to show them where it resides!), they had no clue of such a thing exists! I don't think they know a lot about modern engines yet try and learn things on trial and error. Also I don't find them paying a lot of attention to detail, which I believe is a critical thing for diagnosis. Greatly appreciate if you/ you know of anybody whom you could recommend for me so that I could give it another shot to further narrow this down. Thanks!

I got the mechanic to clean it today, the way you mentioned. It was completely covered with sludge and it took some time to clean it. I ran the car for about an hour and the problem still persists... Just by looking at the amount of sludge the filter was covered with, I guess there's possibly a lot more sludge inside the oil path. What options do I have now? Should I try an engine flush or would that be another rip off? My mechanic says maybe we could try pulling out the oil pan and clean whatever that is possible, without trying a complete de-carbonizing. I bought this car in February this year and I have personally paid a lot of attention to it with on time oil change and stuff. There had been 2 previous owners and I am not too sure how well it was maintained yet it didn't look like it was hacked. Also, I did not have such issues at the time I bought it and there weren't anything strange that I could notice. The engine oil I have been using is BP Visco 3000. Not sure what type of oil used by previous owners.... Thanks!

Quick question, by OCV, are you referring to Camshaft Timing Oil Control Value? Thanks!

I replaced the knock sensor and didn't make any difference.... Thanks!

Thanks a lot for the quick response! No, I don't think an OCV filter was cleaned at any point, though they pulled out the VVTi sensor/ module to check if it was functioning. I will get this cleaned and check again. Thanks a lot for the pointers!

Hello experts, I own a Toyota IST (2002) model. This model has 2NZ-FE VVTi engine (1300cc), driven about 85,000 KMs. Couple of weeks back, it started making an occasional knocking-like noise and I realized this only happens between gear shifts (automatic shift), specially when i drive slow. To be specific, if I drive slow in traffic, when i slightly accelerate and when it is just about to shift from 2nd gear to 3rd, it starts with this rattling noise and after a couple of seconds it goes away. I never get this at idle or even if i rev up the engine and only happens when driven. I wasn't too sure if the noise was coming out from the timing chain compartment, therefore I took my car to my regular mechanic which he overruled the timing chain after checking, suspected with knocking and advised me to try an EFI tune up which didn't make any difference. Then he suspected the knock sensor and/or the coolant temperature sensor to be failing intermittently, which i replaced them, still no luck. I also replaced the mass airflow sensor. I must say that it never came up with a "check engine" light and multiple scanning reports showed that tuning was right on and didn't indicate anything wrong. After consulting many repair folks with no luck (which most of them confirmed that it was knocking yet unable find a proper cause), I finally decided to try my last resort - took it to Toyota for a full inspection of the problem. They opened up the hood, inspected the noise, had a test drive. Their diagnosis was that it is caused by a worn piston rings or a valve problem. They also did a compression test and confirmed that cylinder 2 has less compression (around 8:0) which the other 3 cylinders have the expected 10:5 ratio. I don't consider myself a geek in this field yet I am not a dummy either. I do have some knowledge of how it works and what could cause what. Therefore, though my only lead is to go by Toyota's diagnosis, I would like to seek your expertise and opinions with regard to this before I go for an overhaul of the engine. Could a worn piston ring or values cause an ignition knock or a similar noise? I am truly worried if I would end with bigger issues if I don't fix it right now itself. It would be great to know if I have any other option and I am willing to take my car to any expert in this area. Greatly appreciate your thoughts... Note: I do not have any symptoms of oil burn and do not get any blue smoke coming out of exhaust. I also get good gas mileage. Didn't notice a timing miss either... Thank you! -Isuru