Hey I have a tt engine out of car and id like to test the det sensor so I dont put it in and realise I have a 34. How do I do this? Im not too familiar with electriconic side of things, but is it the same resistance test using a multimeter as if it were in the car? (resistances are still there if theres no power going through right??) or does it need to be at like operating temp or something?
IF you have an oscilloscope. You can connect it to the DET sensor and then wack the sensor on the table and see if it has any output. You should see a series of ringing waveforms from the shock. The device is like a capacitive electret microphone in the way it works. Its a capacitive device and a resistance check is not always accurate.
or you could just measure resistance across the sensor. If you get the right resistance you won't get the code. Doesn't mean the sensor works like it should ofcourse but almost always code 34 is because of a bad connection between sensor and harness in the engine bay / ecu and not because the sensor is actually faulty.
If your det sensor looks old and melted its probably a good idea to put in a new one. Even if you test it and it works, there is no garuntee it will not die tomorrow. It is good practice to replace these things while the engine is out. Especially the det sensor as it is one of the most time consuming (its either complete upper and lower plenum removal or complete gearbox removal.) item to replace. It would be at the top of my list of things to replace while the engine is out after the complete 100k service, the reason behind this is the labour to replace the thing is enormous compared to the value of the part itself with the engine in the car, so the cost of doing it now is far lower than when the engine is back in - your call. Try to replace things which will destroy your engine if not replaced as no.1 and no.2 as things which are hardest to replace with the engine in and have a good chance of failure. 3 is everything else and 4. is mods just my $10K worth I replaced mine last time my engine was out.
I was actually looking at this today and the 2 ways to test a knock sensor is as Tektrader describes and by seeing if timing retards with a timing light as described in the link below (I have never tried this and don't know if it works). But as your engine is out the oscilloscope method is probably the go. http://wiki.answers.com/Q/How_do_you_test_a_knock_sensor_to_see_if_it_is_bad Make your own oscilloscope: http://www.jaycar.com.au/productVie...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID= http://www.ledametrix.com/oscope/index.html
Its a piezo crystal the same as your BBQ lighter. a knock or hit gives a high voltage output , BUT you need a cro to look at it . a molten lob as it usually looks with age is no indicator that it wont work. good wiring connections are very important VERY... 1/2 meg ohms to engine is correct bit really needs knock test to confirm working.:zlove:
Surprisingly I do Did an electrical engineering course for my degree last semester. But no longer have access to the oscilliscopes unless I sneak in...
Just put new one in To be sure, but dont buy from Nissan get one from Ebay. I did and it only cost me about $40 or so. Andy
It looks clean, not sure how old it is or anything. Like with many other parts of the engine. Some parts were obviously pretty fresh, like every single hose was pretty new. Ill probably get into one of the labs when uni starts and use their CRO. Till then, could someone tell me what other parts are worthy of replacing or having a look at while the engines out? So far i only know det sensor and 02 sensors. As well as all the hoses, vaccuum and water but ive done that already. How hard are 02 sensors to replace with engine in?
