decrease in MPG

[benchthug]

Im really concerned about the drop of my mpg from 30 it dropped to 19... i dont know what happened... im using 82 octane here in chicago... but this happened when i changed my air intake... to a CAI... anybody experiencing the same thing that im experiencing...

[pfc369]

my mileage is going down from 32 to 30.5 overall average. your octane must be 87 which is the min. if i use 89 octane i can get 2 mpg more.question: do you have to remove the mass air flow sensor to install the cai or do you still keep it? i am new on this.

[CodeRed]

have you been leadfooting it around town a lot?

[matttail]

I don't know what expirence others have with this, but frequently compact cars like this that are designed for fuel economy don't like it when you change up air flow though the system. The same can happen with putting on a muffler with a larger flow. The car is designed for a certain pressure, and when you put in a 'preformance' air filter it may well not be designed for fule economy.

[benchthug]

no i was driving carefully since my last full tank... every full tank i have i always reset the odometer... with a full tank i can get a 210 miles before the lights go on... earlier today i had another full tank 10.741 gallons with a 211 miles on the odometer its a littler better than my last one 11.830 with 210 miles... i think it has to do with the octane... but im using 93 for my last 2 tanks... ill try to revive this message again next week see if there is still a decrease or increase...

im thinking i might be getting too rich of an air in the engine...

[Samyo]

I've always heard that a CAI actually boosts the MPG... I'm curious now. Any Versa owners with CAI's care to share? I'm wanting to get a CAI but the MPG drop isn't really backed up by a sizable performance margin is it?

[Ever Victorious]

You know, until I came to NICO, I had never heard of anyone buying a CAI for fuel economy, only for performance. The two are kind of polar opposites.

My opinion (uneducated, since I've never actually owned a true CAI) is that you're indeed getting better airflow, which causes the ECU to request the correct amount of fuel for the increased airflow, which means you're pumping fuel quicker than before... so you're expending it quicker than before.

Makes sense to me.

[Samyo]

Of course different engines respond differently to an intake. It could be that the Versa loses fuel economy. As far as making the car more fuel efficient, a cold air intake introduces more air, colder air than the engine is used to. I don't see how the fuel/air mixture will be changed since there is a computer to regulate the mix. But I have heard of many cases where MPG is raised. I was wondering if anyone has made a mass air flow sensor for the V. That would help let more of the new found air in at least.

[Demonspawn]

since i added mine the best MPG i have got is 32 MPG.most of the time it is 29 to 30 MPG.

[biggie]

When you installed the CAI, did you make sure to disconnect the battery? If not it needs to be done so the ECU can reset.

And yes, use 87 oct or higher.

[07Vsdn]

i haven't added an intake to my wife's versa but i have an '06 mustang gt that i added a jlt2 intake and tune to. they were saying that there would be a bump in fuel mileage but none seen. in fact it got worse; as many have reported on the mustang forum.

certainly part of that comes from the fact the tune unleashes the mustang so i run it through the gears at every stop, but i also drove 3 hours highway going an easy 65 and only got just over 23 mpg when i used to get 24-25...

i remember when i had my mazda protege5 and on that forum a lot of people were putting injen intakes onto their's and i remember one of the selling points was increased fuel mileage but i don't remember anyone ever testifying to successful results on that end.

so, yeah, don't believe the intake and increased mileage hype.

[CodeRed]

my mileage is going down from 32 to 30.5 overall average. your octane must be 87 which is the min. if i use 89 octane i can get 2 mpg more.question: do you have to remove the mass air flow sensor to install the cai or do you still keep it? i am new on this.

Yes you have to take out the MAF and install it in the new CAI not too hard unless you drop it....

[benchthug]

so far ive been driving around town below 3000 rpm and for the most part staying at 2000 rpm... if hopefully this one flushes out the old octane and have the 93 takes it place completely... i dont think the gas evaporate due to heat right hahaha....

[Tacuvito]

I don't think putting higher octane will have an effect on fuel efficiency. But you did install a Cold Air Intake! that is your problem right there! While many Cold air intakes help performance, I don't remember hearing of one that helped with fuel effficiency. Keep your car stock and watch your rpm's. I keep mine at around 2800rpm's in sixth gear which translates to 60 to 65 mph, and my gas milage is around 32.1 mpg.

[GoodbyeCavalier]

I dropped mpg big time when I switched from 91 to 89 i dipped from about 30 to 22 mpg for a tank fully recovered about two tanks afterwards.

[pfc369]

Codered: thanks for the answer. maf is the sensor for the computer to determine how much fuel to send to the injector. so if you takeout the maf to install the cai and the computer will send fuel at random rate then.

[benchthug]

okie i understand that the mpg will drop a 1-5 average but if your mpg drops 12mpg well thats something im worried about... i dont know if i shorted out the MAF i doubt it because it will light up... or its just the MAF is not tuned right... should i buy that AFC thing... i have a CAI and a full exhaust system on my civic and the MPG didnt dropped it has b18c engine on it... so i dont see the reason for the drastic drop of mpg on my V... should i get the ecu checked out???

[biggie]

okie i understand that the mpg will drop a 1-5 average but if your mpg drops 12mpg well thats something im worried about... i dont know if i shorted out the MAF i doubt it because it will light up... or its just the MAF is not tuned right... should i buy that AFC thing... i have a CAI and a full exhaust system on my civic and the MPG didnt dropped it has b18c engine on it... so i dont see the reason for the drastic drop of mpg on my V... should i get the ecu checked out???

When you installed the CAI, did you make sure to disconnect the battery? If not it needs to be done so the ECU can reset.

Did you answer this yet?

[benchthug]

yes i disconnected the battery... i followed the directions :P

[versaspeed.com]

On my Versa 6mt which has the AEM CAI and a Tannabe Exhaust I average (with major lead foot) 21-23mpg in town with A/C on, this is with gear changes at around 4000 to 5500 RPM's.Now if I change my shifting to a normal 2000 to 3000 its around 26mpg, city driving with A/C on using "Summer Grade" California regular unleaded.And the 26mpg average City is what I had when I first bought the car (stock). I now have 23 thousand on the car.All my current cars have the same type of modifications and the same rule of thumb, drive them hard and millage goes into the toilet drive them normally and it's what is pretty much normal for the vehicle.But this has been what I have noticed in all the cars and years of driving in So.Cal. so it might be different in your area with different gas formulations etc.

[benchthug]

yes i from cali too... LA to be exact... but im here right now at great lakes, IL and this place sucks hehehehe... im going to the dealer today to get a diagnose on my v... it probably the gas or it just the mixture probably wrong or probably the seal is not good... ill post some updates when i get back if there is any...

[benchthug]

okie i just got back from the dealer i cannot interpret the numbers but here is the reading that they gave me...

ecm eng speed 688 rpm, mas a/f se-b1 0.98v, b/fuel schdl 2.1 ms, a/f alpha-b1 115%, coolan temp/s 203 f, a/f sen1(b1) 2.125v ho2s2(b21) 0.57v, ho2s2 mntr(b1) lean... you guys know how to interpret this... they said im running lean on the engine and it giving more fuel that it supposed too... can an afc fix this...or a regular dyno tuner can tune my car... or another reset for the car is needed...