Canadian Nissan Truck Club

I'm having an acceleration problem with the X. I have a Bluetooth obd2 adapter, and I can see all the sensor inputs. But when driving it, the power is not always there... The only thing I can see is that even when the truck is sitting with key on engine off, the maf sensor reports 0.5 g/s when I would think it should be at zero, and the reading while running is slightly off from the spec as well (but just a little). I have tried cleaning it but it made no difference. Inspected the wiring and didn't find anything. Fuel economy is okay I guess. I'm getting about 400-450k to a tank. It takes me about 2 weeks to do that many km.

Should I take a chance and throw a new one on there? My next step before that is to check the continuity between the connector and the ECU plug. Does this thought process make sense?

If all the connections are good then testing for continuity would be a good approach but a pain.

Is there just the connection at the sensor then at the ecu or is there anything in between?

How much is a new sensor or pull one from a yard? If it is not much then might be worth putting one in and seeing if you get better results.

Well the vehicle run with the MAF unplugged? Some vehicles go into a default fuel map in this case and it can be a trouble shooting tool.

Is there a testing procedure for the maf? Most sensors have a specific resistance when they are inactive you can check.

^ Presuming the engine will run somewhat normally with the MAF unplugged.

Specs should be around the net somewhere.

Nissan and Ford both have a MAF sensor that has a set reading to be able to determine whether there is an electrical connection at key on, engine off. That's just telling you that the electrical circuit is complete and that the sensor is operating. That circuit needs a voltage check at varying throttle positions and have that correlated to the resistance that the MAF is supposed to have. Which I assume is in the FSM. That is what I have learned from South Main Auto channel on YouTube!

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Still have not looked into this any further, I'll see if I can fiddle with it tomorrow before the wing meet.

SpecialWarr wrote:Nissan and Ford both have a MAF sensor that has a set reading to be able to determine whether there is an electrical connection at key on, engine off. That's just telling you that the electrical circuit is complete and that the sensor is operating. That circuit needs a voltage check at varying throttle positions and have that correlated to the resistance that the MAF is supposed to have. Which I assume is in the FSM. That is what I have learned from South Main Auto channel on YouTube!

Interesting. To measure the resistance and/or voltage you would have to have the MAF plugged in. How would you get the meter connections hooked to it?

You need to 'backprobe' the circuit to get live measurements. That's when you take an insulated needle and stick it into the rear (wire side) of the connector on both of the wires that you want to look at and connect them to your multimeter. If you have a really sweet tool you should be able to see voltages between 0.50 and usually 4.96 or so.... mine is not that accurate so I have to estimate a bit.

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When probing the electrical connections from the bottom of my dodge fuse box I just used pliers to jam a small drill bit in there.

Well I swapped out the sensor with another one... And the truck runs fine now. But the reading on the live data is the same! Wtf. Oh well. Don't care, I just want it to run well. Almost 19mpg on the last tank of fuel though...

Are the readings taken from the ODB or from measuring voltage at the plug?