92 VX Seeking 50+ MPG

[Lovemy92vx]

Hey guys and leety in California. I am "manning up" and starting my own thread.

I love my 92 VX. I Know I don't know it's real history, but it is all original, in great shape other than the paint on the roof and the hood: Tahitian Green Pearl (hence her name "Pearl"and I've never named a car)
Found it on eBay and bought it sight unseen. 255,000+ miles, bad paint and all. ($2,500 if you're curious).

Flew to One of the "villes" in North Carolina (Outside Asheville).
Put on new tires and drove it 1,500 miles back to elevation 5280, Denver CO!
Despite the conditions (wind, 18 wheelers, hills and mph 65-75), I got mpgs from 44-48. I was on the road all day long in the late August heat wave (w/little to no a/c!

Since then I've had immediately necessary maintenance done:
Major tune up (ran like a whole different car)
Fuel filter
Valve cover and gasket
Thermostat
Three oil changes including a couple of BG's products to clean the dirty engine
Two radiator flushes (not standard Honda stuff in there)
Cleaned injectors
Plus some minor brake work, replaced an axle.
The best mpg I've gotten is 48.6.
The "worst", 37.17.
I am using Road Trip (app) and have confirmed my odometer and trip meter against a mile marker. Yay they match! Boo odometer is right!!

The thing is that there is often up to ten mile variation per fill up is interspersed--a couple of 47 mpg results then a 37 and a 40 show up. Some known variables allowed for the low numbers, side wind at highway speed, cold weather...when they stayed low for three readings, we discovered a inoperative thermostat.

Now that I've replaced the broken thermostat and had the injectors well cleaned, I can't wait to see the results. I also set the tire pressure to the manual suggestion. Of course, since my commute is only 14 miles a day, it will take a while to reach half a tank so I can refuel! (Bummer :-)

[Baltothewolf]

Tires also make a massive difference in MPG. Going from my old set to my RE92's I saw a minimum of 7mpg boost. RR makes a huge difference apperantly.

[Lovemy92vx]

I'll add those to my wish list. They seem to be $ and hard to find for my car. Advice on that? (Thank you)

*I had Falken Sincera 828 175/70-13 installed before I left Asheville.
They were a great price, but I wasn't thinking RR at the time. Maybe. I made a lucky choice?
I have Defenders on my 97 HX (which surprised me w 54.6 highway over 160 miles.)

[elhigh]

My MPG took a big dip right after I got my HCH back from an alignment; I found out (over halfway through the tank) that the shop had politely set my tire pressure back to the manual's recommendation: 30psi! And one side was actually more like 28.

When I got the car the tires weren't new, and I immediately pumped them up to about 45psi all around. Mileage took a big jump, and I got another 20,000 miles out of them. If higher pressure adversely affects tread life, I haven't seen it yet. Do note, however, that it will affect your tires' grip.

[user removed]

Try this for more consistent tank fills. Left rear tire on top of the 2X4 will raise that corner of the car and get the air pocket out of the tank. Two clicks on medium speed of the pump with a few seconds of wait between them.

regards
mech

[Lovemy92vx]

This was posted with the main point left out.
I stopped at a tire store to raise my front tire pressure. I decided to double check what they had done and one tire was set to 45 the other 38. Some favor...�� ...
My tire sidewall says 51 max psi. What is best?

[Lovemy92vx]

Originally Posted by Old Mechanic

Try this for more consistent tank fills. Left rear tire on top of the 2X4 will raise that corner of the car and get the air pocket out of the tank. Two clicks on medium speed of the pump with a few seconds of wait between them.

regards
mech

Do I remove the gas cap when on the 2x4? Is there a wait for air to move?
Then I drive to the gas station. Do I remove the nozzle?
Could an air pocket explain overspills at the pump?
Thank you very much. :-)
Michelle in Denver

[user removed]

I drop the 2x4 out in front of the tire, before I get out to refill. Gas cap off after I get out. I like to run the pump on low speed (first click) until it shuts off automatically, then wait a few seconds and top it off.

If you are spilling fuel, then you might just listen to the gas level rising in the filler neck and shut it off when it gets to the top. I don't think I have spilled any gas in a very long time at a gas station, years at the least, maybe a decade.

You don't want to fill it to the top of the filler neck, about 4 inches below keeps the evaporative emissions system from being flooded with liquid fuel which will destroy the charcoal cannisters contents. You can probably see the small vent hole in the top of the filler neck very close to the restrictor for unleaded fuel.

Always fill when you have somewhere to go that will use enough fuel so the chance of the fuel expanding into the evap emissions circuit is eliminated.

An example would be filling and immediately parking on hot asphalt in summertime. The fuel in the tank is typically around 60 degrees fresh out of the pump. Heat that to 90-100+ degrees and it will expand and flood the evap emissions vapor line. Repeated events like this could ruin the charcoal cannister that is supposed to hold excessvapor pressure in suspension, to be purged the next time the engine is started.

regards
mech

http://www.aa1car.com/library/evap_system.htm

[user removed]

Originally Posted by Lovemy92vx

Some favor...�� ... My tire sidewall says 40?

My 94 federal vx came with the original tires in 2008. The car had been totalled and sat in an insurance training center for 14 years (controlled environment). It had 27,492 miles when I got it with the rear end shoved into the trunk.

The original bridgestone tires were rated for 38 PSI. I ran them at 38 at 14years age until I replaced them after I got the car repaired and painted. Lost 7MPG average with the Michelin X tires I installed!

Best road trip on the original tires at 64 MPH on the Interstate was 300 miles on 4.627 gallons of fuel on the original tires.

regards
mech

[Lovemy92vx]

Thanks folks. I drove 232 miles (100 mi with my cleaned fuel injectors) and my replaced thermostat. My mpg actually went down to 37.
I refueled today, topped of the tank while positioned on the board as shown. Hope i burped her gas tank okay. I will do this again next fill up to make sure i get it right.
I used and have been using 85 octane and was getting in the mid to upper 40's before we started doing maintenance!
In the meantime, i raised the front tire to 38 (the cheap Falken Sincera rated at 40 psi) and the rear to 35-36.
I am now wondering about what else might be wrong.
Tune up, new fuel filter, well functioning injectors...
Could the engine cleaners be kicking up crud causing some other issue?
I've been reading about PCV catch cans, o2 sensors, MAP sensors, sticking EGR, air filters, fuel pressure regulator...i am trying to learn be researching others threads before I reach out so I dont waste Too much if your time.
i am trying to communicate w my trusted mechanic who is new to the potential of the VX, but is willing to listen and learn.