How to increase Gas Mileage in J30

[Al Dave]

I am having a poor gas mileage. 15 or so. I want to improve it.

From the J30 forum. here is a list what I got need to be done. Thanks gerardjg. The post was a few years old and seems to be extensive. I dontthink I can do many of them by myself.

I am seeking advice on what are the essential thinks that need to be done. I am also trying to figure if it is worth putting the time and effort to do this compared to 5 miles gain per gallon. How long does this last.

Also how good is this BG44k? I read some people in other forums mention this is a scam. Does not really improve the mileage, rather accelerated transmission failure.

The list :

Cleaned InjectorsCleaned Throttle bodiesCleaned Intake manifoldCleaned MAFInstalled recommended plugsBG44k every 3 thousand milesReplaced PCV valves and some hosesReplaced 02 sensorsRun only 93 octaneCleaned all connectors and grounds that I could get toConverted all fluids to syntheticPlus all the routine oil changes and filters.

[yodawill2000]

Scratch the BG44k and make it Redline S1BG changed the formula and took out the stuff that made it the best , Now only Redline has it.

You might pull the codes from the ECU and see if it isn't throwing a knock sensor code. That WILL NOT make the check engine light come on.A bad knock sensor will retard the timing causing sluggish performance and lower MPG.

[Al Dave]

You might pull the codes from the ECU and see if it isn't throwing a knock sensor code.

I may sound a bit novice, how do you pull codes from the ECU. I will try the Redline S1.

Does changing plugs help getting good mileage ?Would changing the timing belt help gas mileage?How much to they charge for timing belt change. The mileage is 120k. The first owner sold at 105k. Did not change the belt. The 2nd owner does not know if it was changed or not. Is there any way to know that?

In June, Changed all the driving belts.Did Transmission fluid flushCooling system flushChanged all the filters.

[yodawill2000]

Getting ECU codes

http://www.nicoclub.com/articl...shtml

Plugs made a big difference for me.Timing belt wont help mileage but if it snaps your engine is GONE.I did mine myself.Water pump , Thermostat and belt ran about 130.00Two days work taking my time.zerothread?id=198122

[naladude911]

woah nice DYI, il check my ECU tomorrow or tonight since im having the same symptoms. I feel like I get worse MPG then my Dad's Tahoe

[Ebbtide]

Make sure your tires are up to pressure and your car is tuned up w/ clean air filter. Do not take off like a bat out of hell, that kills mpg. I do an even combo of city/freeway and get 19-20 mpg at best. If I drive Columbus (all freeway) I get just over 22mpg.

As far as your knock sensor, you can unplug it to make sure it is working. Just disconnect it and drive. You will know within 20 feet if its bad. If it drives the same, it's busted.

Hope this helps.

[GerryO]

Make sure your tires are up to pressure and your car is tuned up w/ clean air filter. Do not take off like a bat out of hell, that kills mpg. I do an even combo of city/freeway and get 19-20 mpg at best. If I drive Columbus (all freeway) I get just over 22mpg.

As far as your knock sensor, you can unplug it to make sure it is working. Just disconnect it and drive. You will know within 20 feet if its bad. If it drives the same, it's busted.

Hope this helps.

We're in complete agreement when it comes to observed mileage numbers, and after having recently removed my plenum to clean it, replace all six injectors, do a TB Heating By-Pass, install a new EGR and PCV valves, new plugs, new fuel filter, clean the MAF, EGR tubes and throttle bodies. I also remove my right shoe, chiefly to save wear on the mat, but for comfort too and doing so possibly helps me drive with a softer touch on the gas pedal. I run 34 psi in the tires.

A properly adjusted TPS is very important, as it determines shift points and crusing rpms/OD lock-up, along with influencing the idle speed and engine timing.

Use the cruise control? Crusing at 50-55 mph instead of 65-70 would make a huge difference. The J30 just does 80+ mph so effortlessly and it's sort of fun pulling away from other cars when going up hills, if you aren't watching the fuel gauge noticeably heading toward E at the same time.
Modified by GerryO at 12:54 PM 9/10/2008

[dcat151]

A lot of getting good mileage is how you drive. But, I keep my tyres at 33 psi and usually get 21-22 mpg in mixed city/highway driving (including driving at 70-80 on the interstate). My mileage would be better if I slowed down on the interstate, but with the speed limit at 70 if I went too much slower I'd probably get run over.

[Chopsaw84]

(((Scratch the BG44k and make it Redline S1BG changed the formula and took out the stuff that made it the best , Now only Redline has it.)))

Hey now...

I still haven't found anything better than BG44k... When did they change the formula and what is the 'stuff' that they took out?

I'm not arguing I just want to know if my favorite product has been compromised.

I've been recommending BG for years based on my experiences back when I was drag racing and so far the only thing that I've noticed is nothing but improvements.

I'm not talking about gas mileage however..., most of the time that I use it is for when I am working on a car that has a stumble or hesitation issue. It works great on dirty injectors, and still does as far as I'm concerned.

Regardless... What gives?

Is BG compromised and if so what is it that Redline has that BG doesn't anymore?

--Anyone?

--James

[yodawill2000]

zerothread?id=332205

[Q45tech]

At a steady speed cruise the MPG is totally controlled by accelerator position since ECU does everything to maintain a 14.7 A/F ratio to optimize cats for emissions.................each bank of injectors is finely trimmed by O2 signal to meet 14.7.

Exceeding a steady 61 MPH will cause you to EXCEED EPA TEST STANDARD and consume and waste gasoline.