Crappy mileage after snorkel install

NMTerras

NMTerras

Suspension Lift
Location
New Mexico
So I've run through a couple of tanks of gas after installing my snorkel/K&N Apollo intake, and my gas mileage dropped to like 10mpg. Do I need to reset my ECM since its getting considerably colder air? I installed the air temp sensor in roughly the same location in relation to the cone filter as the old CAI, other than that nothing else has changed. Thoughts?

Edit: now running a snork, enclosed filter, DT headers and no cats
 
02Xterra

02Xterra

Wheeling
Location
Central VA
You need to stop flooring it to hear that sexy-sounding exhaust!! Hahaha

But yea you can try reseting the ECU.. never hurts to try something
 
Xterraforce

Xterraforce

<img src="http://i164.photobucket.com/albums/u7/ra
Founding Member
Location
Signal Mtn., TN
It could be that the air temp sensor is now getting more or less airflow than it should. I had a similar issue with a '91 240SX after installing a CAI. I ended up plugging the hole back up and mounting the ambient temp sensor out in front of the A/C condenser in an area where it wouldn't be affected by engine compartment heat but also wouldn't be in the direct airflow. The car got 26 MPG before the CAI, 22 MPG with the CAI and temp sensor in the intake tubing, then averaged 28 MPG in summer and dropped to 25 MPG in cold weather after the relocation. Obviously my sensor location wasn't a perfect solution but it worked good enough for me. Naturally the computer and airflow metering wasn't as picky on the old 240 as our Xterras but it might be something to look at. Try to imagine what the airflow might have been on the sensor where it was compared to what it might be now. Unless something isn't right in the snorkel and intake plumbing and is restricting the airflow I really can't think of what else it could be.
 
NMTerras

NMTerras

Suspension Lift
Location
New Mexico
Xterraforce said:
It could be that the air temp sensor is now getting more or less airflow than it should. I had a similar issue with a '91 240SX after installing a CAI. I ended up plugging the hole back up and mounting the ambient temp sensor out in front of the A/C condenser in an area where it wouldn't be affected by engine compartment heat but also wouldn't be in the direct airflow. The car got 26 MPG before the CAI, 22 MPG with the CAI and temp sensor in the intake tubing, then averaged 28 MPG in summer and dropped to 25 MPG in cold weather after the relocation. Obviously my sensor location wasn't a perfect solution but it worked good enough for me. Naturally the computer and airflow metering wasn't as picky on the old 240 as our Xterras but it might be something to look at. Try to imagine what the airflow might have been on the sensor where it was compared to what it might be now. Unless something isn't right in the snorkel and intake plumbing and is restricting the airflow I really can't think of what else it could be.
Click to expand...

Yeah, My betting favorite is the sensor isn't far enough into the cone filter housing and therefore isn't getting enough air. I can either drill out the opening a little and push it in farther (but that means I can't just put the thread plug in if it doesn't work) or pull it out and relocate as you suggest. As of now, I am going to try the reset first, then pull it out, then if all else fails I'll put it farther into the filter housing.

Snork plumbing is good, can hear the air rushing into the head
 
rokdaddy

rokdaddy

Wheeling
Founding Member
Location
New Mexico
^^ The combination of winter blend gas and lower tire pressure due to cold temps caused a 30 mile drop per tank for my X since last November. Airing up the tires brought back about twenty of those miles. You have bigger meats than I have on mine... that could exacerbate the problem a bit.

How high will that snorkel head be after an SAS? You know that oxygen becomes more scarce at altitude...
 
D

drbandkgb

Titan Swapped / SAS'd
Founding Member
rokdaddy said:
^^ The combination of winter blend gas and lower tire pressure due to cold temps caused a 30 mile drop per tank for my X since last November. Airing up the tires brought back about twenty of those miles. You have bigger meats than I have on mine... that could exacerbate the problem a bit.

How high will that snorkel head be after an SAS? You know that oxygen becomes more scarce at altitude...
Click to expand...

HAAHAHAAHAa... Mile high club for Sean
 
NMTerras

NMTerras

Suspension Lift
Location
New Mexico
rokdaddy said:
^^ The combination of winter blend gas and lower tire pressure due to cold temps caused a 30 mile drop per tank for my X since last November. Airing up the tires brought back about twenty of those miles. You have bigger meats than I have on mine... that could exacerbate the problem a bit.

How high will that snorkel head be after an SAS? You know that oxygen becomes more scarce at altitude...
Click to expand...

I live a good 5-600 feet lower than you so it's all good...:kewl:
 
rokdaddy

rokdaddy

Wheeling
Founding Member
Location
New Mexico
NMTerras said:
I live a good 5-600 feet lower than you so it's all good...:kewl:
Click to expand...

We're right at 7000ft so its about 1500ft higher. I estimate that you get about 10% more oxygen than I do...

That's probably why snorkel jokes are the best I've been able to come up with lately.

-Rok
 
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