How-To: Better MPG

[HeX]

I added #19; Valve Adjustment.

I came to learn that an engine ticking sound I experienced is an issue called Valve Lash; when intake and/or exhaust valves have loosened over time causing moving parts to tick occasionally against one another. When these valves dont open or close precisely, the cylinder ports will open slightly late or early and negatively affect combustion, thus fuel efficiency.

Performing a valve job is surprisingly simple so long as you take your time adjusting each valve correctly. Unfortunately, I havent come across any general guidelines on when to perform this maintenance, which leads me to believe it should be done only when you observe the sound or are losing fuel efficiency and are unsure of the culprit. As always, please feel free to share your knowledge and suggestions.

I just filled up a full tank for the first time since adjusting the valves and I calculated 36.3 MPG (299.75 miles / 8.25 gallons) on usual mixed city & highway driving. Thats a rough increase of 3MPG. I'll continue to report my averages after a few fill-ups.

Another fill-up today:

7.88 gallons at 305.75 miles = 38.78 MPG

 

[mc360]

Another fill-up today:

7.88 gallons at 305.75 miles 38.78 MPG

I didnt read the whole thread but might I suggest something, if you have the money buy a new egr valve if not then clean yours out. I bought a new egr for my old hx and mpg jumped from 36-38 mixed to about 40-42 mixed. Also remove your injectors and rail to get to the egr port on the intake manifold and clean tha real good

 

[HeX]

I didnt read the whole thread but might I suggest something, if you have the money buy a new egr valve if not then clean yours out. I bought a new egr for my old hx and mpg jumped from 36-38 mixed to about 40-42 mixed. Also remove your injectors and rail to get to the egr port on the intake manifold and clean tha real good

That's basically #12 (Clean out EGR Chamber; Clean or Change EGR Valve - code P0401). The area below the injectors you refer to is called the EGR Chamber. I improved the wording to include "clean or change EGR Valve". Often times a P0401 code can be given simply from excessive carbon build-up and does not necessarily necessitate replacement of the EGR Valve, as I experienced.

 

[mc360]

lol my bad i didnt read the thread, i was on my phone. but ya i bought a new egr and it helped alot until i got a cel for cat converter which made it burn a crap load of fuel

 

[200STM]

Thanks for this thread, I'm going to try to figure out I'm still getting used to my cars engine but I also want to get the most mpg out of my 1.5

 

[HeX]

Thanks for this thread, I'm going to try to figure out I'm still getting used to my cars engine but I also want to get the most mpg out of my 1.5

Good luck. I'm glad others are finding this useful.

 

[98Romahatch]

Excellent

 

[conor97hx]

Sadly with my experience with the egr valve cleaning did nothing, if it wasn't for helping out with mileage i'd take that system out. Too many problems.

 

[HeX]

Sadly with my experience with the egr valve cleaning did nothing, if it wasn't for helping out with mileage i'd take that system out. Too many problems.

I think thats a bit of an over-statement. The EGR system is pretty simple. If its not a blockage in the chamber then its the valve itself, which is usually the last option. Its unfortunate that you have to replace the expensive EGR but at least it wasnt a complex issue that requires multiple attempts to diagnose like oh so many other issues.

 

[conor97hx]

I think thats a bit of an over-statement. The EGR system is pretty simple. If its not a blockage in the chamber then its the valve itself, which is usually the last option. Its unfortunate that you have to replace the expensive EGR but at least it wasnt a complex issue that requires multiple attempts to diagnose like oh so many other issues.

That is true. I just see the system have so many issues though.


Sent from my iPhone using Tapatalk

 

[Esotericimage]

Just throwing my fart to the wind itt..

My built B20 gets 33hwy and 20ish city +/- 2

My right foot decides my city performance

But theres alot of factors. I use the LS trans which has longer gears. Automatic trans are known for less mpg.

 

[Steven Johnson]

I recently purchased a 98 Ex with a D16y8. I'm not getting good gas milage, but I have a lot of little things I need to fix with the car. Very sluggish, have a knock sensor code (even replaced the sensor, but it's still there. I have a feeling previous owner did a bypass incorrectly), probably needs a lot of little things, like new disty, injectors, fuel filter, etc...

Regardless, once I get the car up to perfect running condition (currently have 195k miles), I'll be taking some of these tips into consideration. I'm typically heavier on the gas pedal, but with my budget being low and needing to provide for my family, I need to focus on every way possible to save money. Thanks for this posting!

 

[HeX]

Im glad this thread continues to help others. Start on the less expensive stuff first, such as the fuel filter, and work your way up. As for the injectors, you should have them cleaned first. Consider sending them to OsideTiger.com. I had them clean my injectors and they came out great.

By the way, I averaged 41.2 mpg on my last fill-up at 8.65 gallons with mixed driving.

 

[Joe Mason]

I just replaced my speedometer because the odometer was broken. I am very excited to calculate my average mpg next time I fill up! Was driving a 2001 Sable before and it was like 19-21 mpg around town. $35 to fill. Now my Civic is $23 to fill. Lovin dat! I've replaced the fuel filter, spark plugs, air filter. Changed the oil and coolant too. And transmission fluid.

 

[Steven Johnson]

Im glad this thread continues to help others. Start on the less expensive stuff first, such as the fuel filter, and work your way up. As for the injectors, you should have them cleaned first. Consider sending them to OsideTiger.com. I had them clean my injectors and they came out great.

By the way, I averaged 41.2 mpg on my last fill-up at 8.65 gallons with mixed driving.

Since my car is my only car, I can't afford to send the injectors in for cleaning and be down for a few days. Also curious, which kind of gas do you use. I've always filled up with premium 93 octane here in New Jersey.

 

[Joe Mason]

Since my car is my only car, I can't afford to send the injectors in for cleaning and be down for a few days. Also curious, which kind of gas do you use. I've always filled up with premium 93 octane here in New Jersey.

Calculate your mpg on premium then do it on regular. I bet the added cost of premium fuel is not worth it.

 

[lethal6]

You are throwing money down the drain running premium in a d - series.

 

[Steven Johnson]

Calculate your mpg on premium then do it on regular. I bet the added cost of premium fuel is not worth it.

You are throwing money down the drain running premium in a d - series.

I guess it just comes as habit since I was required to put in 93 when I had my FA5 with the Hondata tune. Guess I'll start saving a few bucks.

 

[HeX]

Use regular gas. Higher octane means it needs a higher igniting tempurature. Your engine isnt designed for that so your wasting money and unburned fuel.

 

[mc360]

If the car was not designed for higher octane then there is no need to run it unless you changed something major IE: compression, forced induction. Strapping a turbo to a non turbo motor is effectively raising the compression which requires higher octane fuel. If your motors compression is 9.5:1 and your running 10psi boost you are now effectively running 19.5:1 compression in boost