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Does gasoline deteriorate with age to the extent that it will not ignite in an engine?

I am dealing with a "no-start" issue on a "project" car. I know the core issue is that it is not a Chevy! It is a 1981 Toyota Celica Supra. The engine is a 2.8 liter inline 6 with Bosch L-Jetronic fuel injection.

I have done enough troubleshooting and testing to confirm that I have good spark and it appears that fuel is getting to the cylinders. The in-tank fuel pump runs and I can even hear fuel running through the fuel rail when I listen with my stethoscope. The plugs are wet and liquid shot out of the cylinders when I cranked the engine with the plugs out.

During my most recent work session I disconnected the fuel return line and drained a small amount of fuel into a container. I'm not going to say it had an offensive smell but it sure did not smell like fresh gasoline. I have contacted the owner to confirm the last time he fueled the car. I know that it has been driven very little in over a year.

I'm asking this group because I know that there is a lot of experience and knowledge in this group.

Thanks for the ideas.

I have seen gasoline that was so old it would not even burn but it was very old.

Rusty I have found that with old fuel that doesn’t want to start, use starting fluid and get to run to build some heat in the cylinders the old fuel will likely burn. You may want to drain the tank and add fresh.
Could you also have a problem that is just flooding it.

Hi Denny,

Thanks for those ideas. We must think the same. I did not have a helper so was not able to use starter fluid. I agree that replacing the gas is probably on the list.

I am out of town for a week so will try the starting fluid when I am back.

I removed the plugs because I was concerned with flooding. There was quite a bit of gas in the cylinders.

FWIW I have a metal gas can with 2 stroke gas/oil that has to be 10 years old. I use it in my chain saw and the saw runs great. How/if that translates to your issue I can't say. When I fired up the 38 for the first time I poured a couple of gallons of fresh gas into the tank that had 20 year old gas in it. The car started and ran. How much of that was the fresh gas and how much the 20 year old gas I can't say. It was enough old gas that it stuck my intake valves shut and lead to pulling the head to free them up.

I've had the same experience as Tiny.

If I think the gas is a bit old, I add some fresh.

You know you have good spark, so I'd be leaning towards a fuel injection problem.
Could it be injecting so much fuel it's actually too rich to burn from the get-go?

PS
I do recall Dad telling me of a case where his car wouldn't start after some cold weather set in.
He drained off some gas, poured it out on the ground and couldn't make it burn with a blow torch.
So... not all gasolines are created equal.

Drain off a little and see if it appears to burn normally OUTSIDE the engine.
(And your shop of course!) 🙂

In cold weather the gasoline blend has more lighter hydrocarbons as they are easier to ignite. Unfortunately those are the first to evaporate. So if you have summer gas with less of the lighter hydrocarbons in the blend and it sat for a while and you are now trying to get the engine to run it likely will need some starter fluid or carburetor cleaner to get to "light off".

Thanks for the inputs. I will give an update in a week or so.

Gasoline will ABSOLUTELY, POSITIVELY deteriorate to the point where it will no longer burn. Get you some fresh gas (if you have to, cut the line coming from the tank and hook it up to a small container with an electric pump). Have seen this many times on Vice Grip Garage (youtube and other places). Derek will no doubt confirm what I'm telling you here, because he's told us there on too many occasions to count!!

I know that old gas can be a problem. I'm just not ready to bet the farm on it despite what all the YouTube gurus say.

This engine was starting and running through October this year. The owner was using a "jump start" pack because the battery was weak. In November he finally decided to replace the battery after he had a no-start using the battery pack. The battery did not resolve the no-start problem.

One scenario that I am trying to trouble shoot is whether he created a low-voltage/high-amperage scenario using the jump start pack. That could have damaged the ECU.

Because it is a fuel injected car with an in-tank fuel pump it is not very easy to switch to a different fuel supply. We are spoiled with these carbureted engines with external fuel pumps!

I will make one more post to close out this thread. Many thanks for the responses and ideas.

I am fairly confident now that the issue is bad gasoline. As Denny suggested I was able to get the engine to run using starting fluid. One additional trick was that I had to stick a screwdriver handle in the air fuel meter door. That told the ECU to deliver more fuel to the injector. Apparently that was enough to get it running. It would not run below 1500 rpm. My guess is that the injectors are pretty gummed up.

My next step is to drain the tank. Based on the fuel gauge there is probably about 10 gallons in the tank. Thank goodness there is a drain plug! I do plan to change the fuel filter after I get it running on fresh gas laced heavily with Seafoam.

My 2 concerns are whether or not the injectors will clean-up decently and the condition of the tank.

By the way it looks like the alternator is not charging. Which would explain why he was having to jump start it all the time. I replaced the alternator about 4 years ago. All you can get for these cars is one made in China. They might be cheap in cost but they are also cheap in quality!

I was hoping that “bad gas” was the problem for this no-start situation. Boy was I mistaken!

This became quite a lengthy troubleshooting challenge. Ultimately I determined that the problem was bad contacts in the throttle position sensor.

When the throttle was closed the switch was not sending a closed signal to the computer. The computer did not know what to do so it just opened all 6 injectors. So the engine was being completely flooded while cranking.

One other clue was the engine would run for about 30 to 45 seconds if I disconnected the fuel pump. The excess fuel and residual pressure in the system would support combustion.

Once again, resolving this problem proved the value of a great forum. I joined a Supra forum and started posting. There were lots of great responses and ideas. I even connected with a person in North Carolina who has one the original Toyota testing units for this fuel injection system. By coincidence I had a planned trip to that area. We were able to at least test the computer to confirm that it was good. So that prompted me to do more in-depth troubleshooting of the wiring and inputs to the computer.