Bad gas mileage

[BMoj9299]

Hi I have installed a flamethrower ignition coil with an msd distributor cap and rotor. I also have ngk spark plugs and wires. I believe this is what is making my gas mileage go down. Any ideas on what could bring it back up without having to go spend money on all new parts again? Any help is appreciated. I usually have to fill up around 250 miles with about 2 gallons left. I'm just getting tired of filling up all the time.

 

[HeX]

We need some basic details. Keep in mind it is well known than MSD ignition coils dont typically perform well with older Civics, if thats what you have.

What do you drive?
Auto or Manual tranny?
What modifications does the engine have that you chose to modify the ignition?
Do you drive aggressively?

 

[BMoj9299]

We need some basic details. Keep in mind it is well known than MSD ignition coils dont typically perform well with older Civics, if thsts what you have.

What do you drive?
Auto or Manual tranny?
What modifications does the engine have that you chose to modify the ignition?
Do you drive aggressively?

I drive a 97 civic ex with an auto in her. I've done nothing really special to the car. Just a CAI and headers and High flow cat. I've had to replace my o2 sensor recently which helped slightly. I really don't drive aggressively and most of the driving is going back and forth from different towns. A friend told me a better ignition system would help slightly in performance so we did it. It has the d16y8 engine. I just would like better gas mileage again that I had before.

 

[HeX]

Your friend was very wrong. Not only is an automatic Civic not worth upgrading, but D-series in general are all about fuel efficiency. Change the ignition back to stock, perform all basic maintenance with quality parts, use the proper oil weight, go back to the stock airbox using a K&N filter, and your problem should be solved.

Also, read this... http://www.clubcivic.com/forum/threads/how-to-better-mpg.215664/

 

[BMoj9299]

Your friend was very wrong. Not only is an automatic Civic not worth upgrading, but D-series in general are all about fuel efficiency. Change the ignition back to stock, perform all basic maintenance with quality parts, use the proper oil weight, go back to the stock airbox using a K&N filter, and your problem should be solved.

Okay I'll do that thank you very much for your time

 

[Mr.Baker]

For an auto Civic, 25mpg city, 33 mpg highway with about 28 combined avg.
The MSD is pointless, go back to stock. If it ain't broke, don't fix it.
How many miles on the car and when was the car in for a routine maintenance check, fluids and filters changed?
-NGK plugs and OEM Honda wires
-Fuel filter
-stock airbox with K&N drop in filter
-oil change and filter

 

[daperez13]

Your friend was very wrong. Not only is an automatic Civic not worth upgrading, but D-series in general are all about fuel efficiency. Change the ignition back to stock, perform all basic maintenance with quality parts, use the proper oil weight, go back to the stock airbox using a K&N filter, and your problem should be solved.

^This

 

[mc360]

Flamethrower ignition coil, is this the one that allows 2 step launch control to dump raw fuel into the exhaust to produce flames out the exhaust? Ya that will cause bad gas mileage if your over here being a ricer revving at everyone at stop lights.

 

[daperez13]

Aside from the modification you've made, also consider that colder temperatures will affect your gas mileage. You'll idle higher and longer at startup to warm the engine up to normal operating temperature and have higher oil viscosity (so to speak). Due to the shorter days, you'll have higher electrical usage. Hondas, especially Civics, are highly susceptible to electrical changes. Tire pressure will also impact your mileage. But the biggest change in MPG will be your driving style.

 

[BMoj9299]

I'll have to post a picture of the set up sometime to show you guys exactly what I did. But I'll try to get it back to stock so I can get around the gas mileage I used to have. Thanks for all the input.

25 mpg for an auto Civic is about right if you're driving mixed city and hwy.

Any CEL codes?

There any codes being thrown.

For an auto Civic, 25mpg city, 33 mpg highway with about 28 combined avg.
The MSD is pointless, go back to stock. If it ain't broke, don't fix it.
How many miles on the car and when was the car in for a routine maintenance check, fluids and filters changed?
-NGK plugs and OEM Honda wires
-Fuel filter
-stock airbox with K&N drop in filter
-oil change and filter

The car a quarter million miles on her!! But it's last service was just last week.

 

[Mr.Baker]

These would be overly optimistic numbers for a 00 Civic EX auto. Not sure what OP has.

Optimistic?
I was basing those averages off of numbers I found from Fuelly.
I get 28-29 combined with my Ex 5spd.

 

[HeX]

These would be overly optimistic numbers for a 00 Civic EX auto. Not sure what OP has.

I wouldn't call those numbers out of the realm of possibility for a well maintained automatic Civic. 26-28 overall average is about right, with a sedan being on the lower end for obvious weight differences.

 

[HeX]

Note how close 25 mpg is to the lower side of your own estimate.

I don't know why you bring that up when I'm only supporting the average mentioned. He hasnt mentioned his MPG anyways.

@BMoj9299 , please state the average amount of gallons you tend to fill up. You thinking there are two gallons left doesn't tell us that you're accurate.There are alot of people who post while making false assumptions so I only go by clear facts. Keep in mind your tank is about 11.6 gallons if I recall correctly.

 

[Teri]

You may not be aware that the Civic auto gets substantially lower gas mileage than the same Civic 5-speed. In addition, the D16Y8 will generally get lower gas mileage than the D16Y7.

The reason D16y8 gets lower gas mileage because its a SOHC vtec , the D16Y7 is non vtec.

Sent from my SM-G900V using Tapatalk

 

[Mr.Baker]

These would be overly optimistic numbers for a 00 Civic EX auto. Not sure what OP has.

My wifes stock '97 auto Ex with 150k was getting about 28-30mpg combined avg, so I don't see how those numbers are "optimistic", especially considering when you look at real world stats entered into Fuelly.

 

[HeX]

@boofoo , you're getting way too caught up on these numbers. There is a reason why we all are referring to them as averages, so let it go already.

 

[Sevitz5]

I'm getting around 31

 

[HeX]

Why not wait until the OP supplies more detailed information before jumping to a possibly wrong conclusion?

Thats been my point all along. He has yet to provide detailed information about his MPG. I even stated earlier that he stating he gets 250 miles per tank with 2 gallons left is not nearly enough information as we have no way of knowing why he feels that is accurate. We both know the only way to be accurate is to only provide the miles driven and gallons filled. That,'s why I say to let it go because for all we know he's misjudging how much he has left and is actually averaging in a normal range. We all need to wait for @BMoj9299 to provide accurate numbers.

 

[BMoj9299]

Thats been my point all along. He has yet to provide detailed information about his MPG. I even stated earlier that he stating he gets 250 miles per tank with 2 gallons left is not nearly enough information as we have no way of knowing why he feels that is accurate. We both know the only way to be accurate is to only provide the miles driven and gallons filled. That,'s why I say to let it go because for all we know he's misjudging how much he has left and is actually averaging in a normal range. We all need to wait for @BMoj9299 to provide accurate numbers.

I will let you guys know the next time I fill up how much I fill up and how many gallons gets put in

 

[Mr.Baker]

"Combined" is rather vague. The city/hwy ratio matters.

I'll put it to you like this...
My last week, I drive 25 miles a day for work, rural driving, M-F, at least 100+ miles/week. Fill up 2nd week.
My trip meter is at 267, and took me 8.6 gal to fill up, needle just touching the "E", giving me 31mpg.

There is about a 60 lb difference between the 96-98 and 99-00 Ex coupe.

You and others are recommending the OP do various types of work that may be unnecessary

I don't think regular tuneup items are unnecessary, especially if you're not sure when they were done and especially if the car has 1/4 million miles on it.