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| Thread ID: 103000 | 2009-09-09 03:06:00 | TPS Unit (Automatic Transmission) | ronyville (10611) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 808157 | 2009-09-09 22:12:00 | Many thanks SurferJoe46 for your advice and explanation. I also just cleaned my MAF - with carb cleaner (F1 from the USA), and fine paint brush. The input voltage is 12V,(3 wire) but USA Nissan forums/web sites it says should be 5V and others 12V (I think). Why the difference? The signal wire reads 1.25V at idle, and about 1.45 at higher revs (maybe 2000 revs). Before cleaning it was 1.76V to 2.02V (at higher revs). The middle wire reads 0V. Seems in the USA many switch from SR20 MAF's to Z32 MAF's by rewiring the latter. What's the advantage? |
kahawai chaser (3545) | ||
| 808158 | 2009-09-09 22:42:00 | Many thanks SurferJoe46 for your advice and explanation . I also just cleaned my MAF - with carb cleaner (F1 from the USA), and fine paint brush . The input voltage is 12V,(3 wire) but USA Nissan forums/web sites it says should be 5V and others 12V (I think) . Why the difference? The signal wire reads 1 . 25V at idle, and about 1 . 45 at higher revs (maybe 2000 revs) . Before cleaning it was 1 . 76V to 2 . 02V (at higher revs) . The middle wire reads 0V . Seems in the USA many switch from SR20 MAF's to Z32 MAF's by rewiring the latter . What's the advantage? Usually just higher flow rates and the Z32 wire isn't so inundated with airflow that it creates bad resistances and the system goes rich trying to compensate for too much air . Check the color codes on the wires you are seeing this 12VDC and 5VDC on . The 5VDC is for reference* and it heats the wire - but not to glowing incandescence - and it gets air flow over it and changes the return voltage to the ECM . It kinda acts like a reverse-biased thermistor . * Reference is a bad word I believe . It is really a "supply" voltage for the heating of the element . It is created by the ECM in an area sometimes called a Quad-Driver, which is capable of higher amperage than the average printed circuits on the boards . Both the 5VDC and the 12VDC are "clean" current with no waveform on the line . Any waveform will upset the values and mess with the ECM . If the middle wire is black, it is the system ground and should be zero voltage and also have very little resistance to the battery negative post or ground . The wire element gets heated very hot at each start-up for a few seconds to clean it of dirt and contamination as best it can . It cannot however remove all the corruption that gets past the air filter - and this is why I also eschew K&N air filters . They let too much oily debris through the filter media and it ruins the heated element, rendering it either corrupted or useless . |
SurferJoe46 (51) | ||
| 808159 | 2009-09-09 22:56:00 | I agree with the K&N filter - since I installed a similar filter (aftermarket), the MAF has been getting a bit dirty frequently, causing I believe, fluctuating rev's at idle. But the filter looks nice - may have to change to a enclosed type filter. | kahawai chaser (3545) | ||
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