Air Flow Sensor

[cbarr]

My 90 Q45 has had a series of problems hanguing up the transmission to change from 3 to 4 and 2 to 3 and additionally the car shuts off when decelerating (even if you are dioing 60 MPH) and sometimes it restarts (running at speed) if you pump the accelerator and sometime it doesn't staert even if stopped. Thye problem has been erratic. The TPS was changed and forund another air flow sensor from another Nissan vehicle and the problem stopped. Are the air flow sensors interchangeable?? or do they have to be exactly the same part number??How much do they cost anyway??Thanks,:help

[Q451990]

I think they're different from car to car. Someone had sevral MAFs for sale on eBay recently for about $20-30 each. New is about $300 if I remember correctly... you can also search http://www.car-part.com.

I'd also be concerned about your fuel pump and it's controller. How many miles on your car? Do you hear a humming noise from behind the back seat?

Heath

[Q45tech]

Nissan selects the MAF diameter so that under max flow [max rpm] the differential pressure across the unit won't exceed 0.25 psi [roughly 7" of water column].

This max restriction represents at absolute most 1.5%. In other words a 300HP engine might produce 4.5 HP more without the MAF ............just a straight tube of equal diameter and no air straightening/trash screen.

Unfortunately the ECU needs the CORRECT signal from the MAF to operate.

All Nissn MAF generate the same 1-4.8 volt signal just correlating to different air flow mass amounts. The inside diameter is the clue as to what you have. The Q MAF is a 255 grams per second type good [amount of air mass] for 330 HP......before the voltage maximizes. The air flow can be higher just that the ecu doesn't know it's higher.

[Jeff Williams]

Have you tried to clean the old one?

Us the entire can of break cleaner, and soak it good, along with the screen. Make sure your connections are good (I have heard the 90 thru 93 had poor quality connectors).