The effects of OLD gasoline in a classic car

-
I live in California and all the gas is **** most the time....so I have a few bottles of Lucas octane booster and I usually just dump a little bit in here and there if I haven't driven the car in a couple days since I have five.
 
Lucas makes a stabilizer/additive specifically for ethanol-blended fuels. I haven't tried it on anything super long term (more than 8 months or so) but it seemed to work well. I also noticed it gave a slight MPG boost in both my Jeep and Duster but not enough to use it all the time.
 
Krooser said:
In 2015 I drove my F350 back home to WI from LA and started out with 37 gallons of 11 year old gas. At $4.00 per gallon there's no way I was draining the old stuff
Click to expand...
Cowabunga...I'm amazed that it ran on that stuff!
 
dano said:
Is the electric choke hooked up? If yes, these need adjusted to increase or decrease the speed as to which they come off choke.

For either the Holley or the Demon, was the high idle in use?
Click to expand...

Neither were. The Holley is a manual choke, the Demon originally was an electric choke but I removed and trashed the parts many years ago.
The Demon has an electric choke now but the fast idle setting is a mile off. I need to set that up.
THe main problem was the bad/old gasoline though. With fresh fuel, it started and ran normally. Once the choke and fast idle is properly adjusted, it should be tip top.
Thanks, Greg
 
It seems to me my old cars give off more carbon monoxide and other bad fume as the gas gets older, like I have some in one car that is bout 1 tr old
 
Kern Dog said:
Although I enjoy the show, The Walking Dead really stretched the truth in many ways. They had people driving cars YEARS after the world crashed using gasoline that was several years old.
That would never work here in California.
Our gas is "Up to 10% Ethanol". Testing has found it to be approximately 6% as of 2 years ago. I've read that the Ethanol gas has a shorter shelf life than pure petroleum based gasoline.
I have had a persistent cold start problem with my Charger for several months. The last time I drove it to a gas pump was early this year. Since then, I've driven it less than 100 miles. I've been working on several things with it including a new Classic Auto Air heater and A/C system, wiring upgrades, windage tray, radiator, water pump and housing...all sorts of things. Because of that, the gas in the car got old.
So, since about June of this year, it ha been hard to start and when it did, it ran really rough. The Air/Fuel gauge read really lean as well. It slowly smoothed out as it got up to temperature. Once it was warm, it ran great. The Air/Fuel readings read rich as it warmed up, with numbers in the 12 to 12.5 range.
I looked for the causes of the rough cold idle. First off, I did NOT have a choke on the carburetor. This Demon 850 always allowed the 440/493 to run pretty good at cold starts without a choke. 20-30 seconds of feathering the throttle and it would run on it's own. The rough running felt like a serious misfire, as if 4 holes were just not getting spark. I swapped parts around including the distributor, spark box, ballast resistor, coil and I even tried a different carburetor. The Holley 750 from another car was the only thing that made a difference. With it, the engine ran like it used to before any of the problems started. I had my Demon rebuilt and the man installed a new electric choke kit. Yesterday I put the 850 back on and the car ran just as bad as it did before. What the heck?
It turns out that this 11 month old gasoline was the problem. Today I drained the tank and the bowls of the carburetor and poured in fresh 91 octane gas. The car runs great again.
Why did it run good with the Holley 750? I think that it was because it still had gas in it from the other car!
MY understanding, after reading up a bit, is that as gasoline ages, it evaporates and loses the volatile compounds first. This leaves behind a thicker, yellower and less potent blend. Cold starts need MORE fuel than a warm start. The fuel needs potency to ignite.
I guess I'll keep some Sta-Bil on hand if I think the car will sit for more than a month.
Click to expand...
The thing that most people don't realize is that right now butane and/or pentane is also blended into gas (at least here in NC) so out of a gallon of e10 gasoline 75% is gas, 15% is butane and the other 10% is ethanol. They claim the butane does not come out of suspension with the gas but I've never distilled old butane blended gas to find out. I work at a petroleum terminal and I never use gas additives but I truly believe Stabil works when a vehicle sits. Just my 2 cents.
 
barbee6043 said:
True, but they seem to give off worse fumes when the gas is somewhat old. Maybe time for a tune up, get them up to100 or and blow them out!!
Click to expand...

The smell is from unburned hydrocarbons (unburned fuel), old engines do emit more carbon monoxide and oxides of nitrogen (NOx) but neither of those have a smell. Modern cars with catalytic converters absorb a lot of any unburned fuel in the exhaust which is why they smell a lot less noxious when running, they also have EFI and better combustion in the engine to reduce unburned gas ending up in the exhaust in the first place.

The old gas burning in an old car smells worse because it's not burning as completely (more unburned fuel in the exhaust) and there are other weird chemicals that form in old gas to give it that odd smell. A new car with EFI will self-tune to compensate and the cat will capture most of the nasty-smelling stuff.
 
You must log in or register to reply here.
-

Back
Top