I have a JDM B16a in my hatch. I bought it like that... So I noticed that I kept going to the gas station frequently... So I filled it up, 10 gallons, reset my trip A, and over the period of 2 months, noticed that I am getting between 20 mpg, and 24, when at its best. I even changed my oil, spark plugs, and spark plug wires before setting out to test this. Anyone know why I could be getting such low gas mileage for a 1.6L? All it has are a full catback exhaust and cold air intake. I took a look at the ecu, and it has a P30, with a wierd name written along it. I was thinking of ordering a new one off phearable.net(can't send my in to be chipped). Do you guys think this will help?

 

Try using a virgin ecu (NOT CHIPPED!), changing your fuel filter, checking your fuel pump and injectors.. Check your dizzy?

 

Is the P30 the one that came with the B16a? And for the dizzy, if need replacing, off what car should I get it? I know the B16a is an OBD0... and I am running an OBD1 ecu...

 

how do you drive and have you cleaned your air filter lately.

 

I havent cleaned the air filter lately, and I do mostly highway driving, only doing 80 mph at the most.

 

What colors are the wires running to your intake air temperature sensor ?

Try pulling the IAT sensor & looking at the tip of it, better yet use the helms manual and a meter to test the sensor

 

b16 dnt get the best gas millage. i got one in ma hatch. and my b16 tranny doesnt help cus its so short

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16a3delsol &raquo;</TD></TR><TR><TD CLASS="quote">how do you drive and have you cleaned your air filter lately.</TD></TR></TABLE>

Chipped ecu + VTACK = no mpg

 

Whats the IAT sensor have to do with gas mileage just curious

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mortificationrock &raquo;</TD></TR><TR><TD CLASS="quote">Whats the IAT sensor have to do with gas mileage just curious </TD></TR></TABLE>

IAT sensor reports intake air temperature to your ecu which changes how much fuel is injected etc.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nefariousyellow &raquo;</TD></TR><TR><TD CLASS="quote">I havent cleaned the air filter lately, and I do mostly highway driving, only doing 80 mph at the most.</TD></TR></TABLE>

isnt 80 mph on a b16 tranny somehwere around 4k rpms?

if so then that is gonna lower the mileage a bit

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92ehatch &raquo;</TD></TR><TR><TD CLASS="quote">

isnt 80 mph on a b16 tranny somehwere around 4k rpms?

if so then that is gonna lower the mileage a bit

</TD></TR></TABLE>
at 75mph, on a b16 tranny, you will be doing 4500rpm. so at 80mph it'l be close to 5000rpm.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Lordofdark176 &raquo;</TD></TR><TR><TD CLASS="quote">
at 75mph, on a b16 tranny, you will be doing 4500rpm. so at 80mph it'l be close to 5000rpm.</TD></TR></TABLE>
damn those are some really short gearing! your also hitting vtec on that speed.

 

I was getting shitty mileage like that for a while on my b16a. It turned out that my intake cam skipped a tooth. I adjusted the cam and my timing and now I have more power and better mileage. When I cruise on the highway in 5th between 4 and 5k I can get 31mpg avg hitting vtec out of every toll booth and my rear wheel bearings need some attention so I may get more mileage after I pack them full of grease.

Also, the ethanol that they are putting in gas now kills mileage too.

Have you checked your tire pressure?

 

first off, your ecu doesn't look chipped... in the second pic:

the top left corner has what looks like a chip outlined in white on the PCB.
that is normally where the chip for "chipped ecu's" go.

second, is most of your driving in town/city or on the highways? if you're not cruising at highway speeds your gas mileage will def be in the 20's.

 

i recommend getting your P30 chipped with a programmable EPROM and street tune it using a wideband and uberdata/crome.

get a kit like this:
http://www.moates.net/product_...id=42

 

i also have the same problem!!
i average between 22-24mpg, no matter how i drive!!
ive changed plugs, leads, dizzy cap-arm, oil change and fuel filter, clean tb, cleaned cai, the list is as long as my arm,
no difference at all,

 

if your car is not stock, you really should tune it so you're not wasting gas.

either your fuel maps are off and/or your ignition timing is off...

 

Also remember driving habits play a large part in gas mileage. If you do allot of hard accelerating, your not gonna get the best mileage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nefariousyellow &raquo;</TD></TR><TR><TD CLASS="quote">So I filled it up, 10 gallons, reset my trip A, and over the period of 2 months, noticed that I am getting between 20 mpg, and 24, </TD></TR></TABLE>

Dont mean to sound insulting but did you calculate correctly? Any reason why you filled up with 10gals exactly? Is that what it was at full? and why do you care what you filled up with previously if you reset the trip afterwards? The best way to calc (That I know of)

1. Fill up tank to full
2. Reset trip odo
3. Drive till next fillup, fill up full again, note the amount of gas
4. Take the number in 2 and divide by number in 3

Otherwise, points about checking your ecu, tuning, sensors, driving patterns, etc are valid. Check your trunk to make sure you dont have a dead body as well. That extra 150lbs of weight could be dragging you down.


Modified by ekhatchling at 12:48 AM 11/2/2007