# GA16I not revving/bucking



## B12Chris (Dec 14, 2011)

Since owning the car, I noticed sometimes I can't go WOT/half throttle from a stand still or slowly moving, the car will just cut out, then cut back in real quick.

Over the past couple of days it's gotten worse, to the point I can't drive the car. It will start and idle just fine, although it does have the high idle its always had. But the moment I touch the gas pedal, it will stutter and cut in and out, much like it's running out of gas. If I hold the pedal at half way or WOT in neutral, it won't rev over ~3000rpm, sounds just like its hitting a slow rev-limiter. If I tap the pedal quickly multiple times, it will rev higher.

I've replaced the plugs, air filter, and fuel filter with no change. No codes. My gut tells me its the fuel pump, but I also thought of the injector or ECU. The reason for thanking ECU is the only other time it did this, was a few mouths ago when water got in and completely covered the ECU, but it cleared up once it dried. 

I'm about to buy a Walbro 255 pump, which I will need anyway once I turbo it. It just doesn't act like a normal fuel pump issue, at lest not the ones I've experienced. When holding the throttle open and it cutting out, I sprayed starting fluid into the throttle body and instead of revving up, it just boged down. The cutting out is very consisted through the gears also, and won't go over 55 before bucking wildly.


Here's a few vids;


----------



## B12Chris (Dec 14, 2011)

Just to add, my alt is putting out 13.8v and slowly goes down to 13.3v (goes no lower), but won't increase at all with rpm. That sounds kinda' low...


----------



## B12Chris (Dec 14, 2011)

I tried a different type of starting fluid today, and sure 'nuff, it made to engine rev up fine. So it's diffiently fuel. I'll replace the pump first, then injector if I have to. 

Just glad to have it figured out, lol.


----------



## bob89sentra (Sep 15, 2005)

It is not the fuel pump.This screams bad MAF!!! From personal experiance I would put money on bad MAF (mas air flow) sensor. A bad MAF sensor will do exactly what is shown in the video. The cutting out when opening the throttle prior to this problem could have been the MAF going out, but also could be the TPS (throttle posistion sensor). The computer may not necessarily show any codes even if your MAF or any other sensor is bad or going out. In my experiance if the computer throws a code there is definitly a problem, and if it does not there still could be a problem. The computers on these GA16Is are pretty dumb when it comes to throwing a code for walking failures. 13.3V is fine for an alternator output when the battery is charged. When the battery is low the alternator will ramp the voltage to charge the battery and can go up to 14V.


----------



## B12Chris (Dec 14, 2011)

bob89sentra said:


> It is not the fuel pump.This screams bad MAF!!! From personal experiance I would put money on bad MAF (mas air flow) sensor. A bad MAF sensor will do exactly what is shown in the video. The cutting out when opening the throttle prior to this problem could have been the MAF going out, but also could be the TPS (throttle posistion sensor). The computer may not necessarily show any codes even if your MAF or any other sensor is bad or going out. In my experiance if the computer throws a code there is definitly a problem, and if it does not there still could be a problem. The computers on these GA16Is are pretty dumb when it comes to throwing a code for walking failures. 13.3V is fine for an alternator output when the battery is charged. When the battery is low the alternator will ramp the voltage to charge the battery and can go up to 14V.


Thank you ALOT! Thats sounds spot on to what is going on with mine.

Now, where can I actually BUY a MAF sensor for a GA16I? Both RockAuto and Autozone don't list them.


----------



## B12Chris (Dec 14, 2011)

Update #2685346

Turns out to just have been the connector on the MAF, the car runs great now! Even made it to 95 (power dies after that).

Again bob, thanks alot for you're help!


----------

