Gasoline + Ethanol

[tubatom91]

My '37 broke down again . We are ordering a rebuild kit for the carb. and hope that it is a needle valve that is sticking. It died at a very busy corner at high noon today. Just ka-put, dead. Didn't even hint towards starting anytime soon. I rolled it down the hill and swung it into a parking space and left it. I came back with a local tow truck and towed it back to it's garage. I paid the tow truck driver (don't worry I had tow insurance put on it), got in, and cranked it 2 rotations and it started like a champ. . I think the tow truck ride knocked the valve loose and allowed gas into the bowl where the float goes up and down. We are assuming that a rubber tipped needle valve is to blame.

[Todd S. Malicoate]

My '37 broke down again .

Let's diagnose. What happened when you turned the key (or, stepped on the floor starter?) and it wouldn't hint towards starting? Crank but not turn over? Nothing at all? If it's a fuel (carburetor) problem, it would have cranked but not started (no fuel, but spark). If nothing happened, it's more likely a starter switch or poor ground. Bumping around behind a tow truck fixed the problem? That could be a clue, as well.

Before you order that carb kit (where are you getting one???), make sure it's a fuel delivery problem. I would imagine a kit for something that old isn't cheap.

I'm still not convinced your problem is ethanol-related. Someone claimed earlier that ethanol eats rubber made before 1989 or something, which is just ridiculous. Henry Ford designed the Model T to run on ethanol, and he certainly didn't have access to the space-age materials of today...just plain old petroleum-based rubber.

I have several friends in the car clubs around here that own and drive older vehicles like yours, and they run fine on pump gas. My 1965 Belvedere, that I rarely drive, does fine on it as well. The two barrel Carter and fuel pump on that 318 are both still original. All I do to it is add a bottle of lead substitute every other tank...someday I'll rebuild the heads with hardened valve seats.

Back to the topic at hand, I have now checked the mileage from six tanks of gasoline...three from Valero (who claims no ethanol in their gas but charge 5-10 cents more a gallon) and three from the nearby "On Cue" station (which has the stickers "up to 10% ethanol" at the pumps). It's not a large enough sample to be scientific, but I'm getting 3-4 mpg more with the Valero gas...enough to keep me going there. On a 15 gallon fill-up, I'm paying $1.50 more to get 60 more miles...well worth it.

[tubatom91]

I drove the car for about a 2-3 miles and as I was coming to a stop it crapped out. It crapped out at a stop sign before the permanent crap--out. The starter works fine. I have drained the battery a few times (6volt system)

[Todd S. Malicoate]

Yes, but what did it do when you tried to start it? Nothing at all? Crank but not start?

[SplatterTone]

Most important and what has heretofore been completely ignored: Exactly where on the dash was the plastic Mary situated?

[tubatom91]

it tried to start, but there was no gas for it to run on.

[Todd S. Malicoate]

I'm leaning more toward an overheated ignition coil. Sitting for a while and then being towed allowed everything to cool down and the car started normally again. Internal carburetor problems aren't usually solved so easily or randomly. Also, assuming it was a fuel delivery problem, it would have taken much more than two cranks for it to start after it was towed...you would have run the bowl completely dry trying to start it before...that old mechanical pump ain't that fast. Did you do anything to confirm no gas in the float bowl, or are you just guessing that's it?

Keep some starting fluid in the car...if this happens again, try spraying some directly into the intake to confirm the engine isn't getting fuel. If you're getting good spark, the engine will run for a bit on the vapors.

Anyway, no harm would come out of rebuilding the carburetor whether it's the problem or not...again, where are you going to get a kit?

[SplatterTone]

Wondering how warming up a coil could cause it stop sparking, a little research turns up this. Interesting, I think.
http://www.newton.dep.anl.gov/askasci/e ... g99514.htm

[tubatom91]

I am leaning towards the carb. because the car has a brand new ignition coil in it. I dont think it is anything electrical because last year we replaced the rotor, points, distributer cap, spark plug wires, and spark plugs. The fuel lines are new and the pump is new. My Grandpa had this very same issue on his '28 Whippet. I have a can of starting fluid in the trunk, it gave a few sputters but quit...just like it did before we replaced the pump. I am going to order the rebuild kit from Kanter auto, I have had good luck with them.

[Todd S. Malicoate]

Well, yeah...if the starting fluid gave you a few sputters, then you probably had good spark. I still don't understand why you were able to start it pretty much right up after it was towed, though...anybody with an older car with a mechanical pump knows it takes several cranks to get fuel to the carburetor, which you say didn't have fuel in it. Weird.

Anyhow, good luck with your carb rebuild!

[tubatom91]

Here is a list of things I have replaced (to avoid confusion on your end and mine ):
fuel pump,fuel lines,fuel filter,battery,points,rotor,dist. cap,spark plugs,spark plug wires,headlight,key(s),and ignition coil. I know that when we replaced the coil we used a voltage tester (a little yellow box with two wires coming out of it) to see if there was enough power. There was. I know that the car has a rather complicated ignition system IMO. It is a floor switch but not a seperate button. When the key is turned a little silver toggle comes out (I pump the gas pedal a few times at this point) You flip the switch to on and push in the gas pedal as you are "flooring it" the starter kicks in. When the engine starts a vacuum switch disengages the starter switch in the pedal. The car also idles fast when warming up but when you tap the gas pedal a linkage drops the idle speed down and the car runs smooth as silk. I figure this info might stir some minds.

P.S. I know how hard it is to diagnose a problem without the car in your garage. The car isn't even in my garage!

[tofu]

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[tubatom91]

I have been in a car that vapor locked. It was in Nashville Tennesee in the middle of summer the high for the day was around 102 degrees, 100% humidity. We were just starting to head back to the hotel after a long day of tours and driving (Car club tour). The 1916 7 passenger touring car that we were in has a 6 inch exhaust that runs under the passenger side floorboard and then under the gas tank that is mounted under the front seat. YOu could pretty much feel the gasoline bubble under your seat. And about a mile later the car crapped out. The way that car beheaved and the way mine behaved seemed to be different. I think the float stuck on the intake side of the carb. Last summer we tried to start my grandpas stakebed truck. The float sutck on the output side and flooded over and onto the floor. The engine backfired and lit the front end of the truck on fire....needless to say we keep a fire extinguisher handy and in every car.

[Rick Denney]

I am leaning towards the carb. because the car has a brand new ignition coil in it. I dont think it is anything electrical because last year we replaced the rotor, points, distributer cap, spark plug wires, and spark plugs. The fuel lines are new and the pump is new. My Grandpa had this very same issue on his '28 Whippet. I have a can of starting fluid in the trunk, it gave a few sputters but quit...just like it did before we replaced the pump. I am going to order the rebuild kit from Kanter auto, I have had good luck with them.

I'm a little curious about the starting fluid only causing a bit of rough sputtering. If the fuel flow was cut off, the engine should run fine (for a while) on starting fluid as long as you spray it into the throat--you are not using the carb for anything with starting fluid except as a path to the intake valves. If it would only stumble roughly, then I wonder if it's not a matter of fuel starvation but rather flooding.

Now, THAT is a problem that is common on older cars, and it IS a problem with the float valve. Rust and dirt particles keep it from sealing, and the float bowl overflows. This problem, unlike fuel starvation, is worst at idle, when fuel demands are the least. The fuel will often overflow the float bowl and run out on top of the engine, in addition to dripping into the throat and causing the engine to flood. This will cause the engine to run rough at idle and possibly die, and because it's flooded, it will not restart until the excess fuel has evaporated. Then, it will start up again just fine. That sounds more like your symptoms.

But you must find the source of the dirt, and I doubt it's ethanol. I would be much more suspicious of rust in the fuel tank--I've never known a really old vehicle that didn't have a problem with rusty tanks. Humidity is inevitable in the fuel tank, and as temperature changes, the tank will breathe humid air in and out through the vents provided on older systems. Moisture accumulates and that causes the steel tank to rust. Ethanol in the fuel actually helps with this by absorbing some moisture so that it can be burned in the engine instead of being allowed to collect in the tank.

Rebuilding the carb is a temporary solution, just as installing a new pump was a temporary solution, if the tank is full of rust. The only solution in that case is to replace the tank, I'm afraid. I have had to do that on my GMC motorhome, and it was still the single most expensive repair I've made--the new tanks (yes, there are two of them) were large and custom-made. I also have had to replace rust-jammed filter socks on all GM vehicles that were older than about 15 years, though that too is a temporary solution.

Don't just throw parts and rebuilds at it. Understand the problem. Cut open a fuel filter--if you see red particles jammed into it, then you have rust. Remove the hose from the pump, and blow compressed air back into the tank (dial the compressor regulator down to about 15 psi, remove the filler cap, and inject the air in short 1-second bursts). That will sometimes blow a clogged filter sock off the sender, re-establishing fuel flow (for a while). But the problem is the rust, not the clogs, and removing the clogs will only provide temporary relief until it clogs again. At the very least, install a good (large) inline filter between the tank and the pump to protect what you have done with the pump and the carb, and resign yourself to replacing that filter very frequently.

Rick "been there; done that" Denney

[Todd S. Malicoate]

Good post, Rick...perhaps a bit too good.

Diagnosis is the key to solving problems, especially in older vehicles like this. Unfortunately, it's much easier to "go with the gut" and throw parts at it.

The only thing I would add is that, if it is rust in the gas tank, there are some excellent products for restoring an old tank. The one I recommend to my customers can be found at http://www.kbs-coatings.com.

Just please, don't yell at your parts guy if/when he gets you exactly what you asked for and it's doesn't fix the problem.

Todd S. "also been there and done that" Malicoate

[tofu]

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[tubatom91]

To make things clear. This is a Buick that has never been restored. The car has under 40K Miles. and It has never been off the frame. (Since tofu mentioned restoration)

[tofu]

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[Todd S. Malicoate]

I didn't realize somebody was still selling no ethanol gas. I assumed that the gubmint had outlawed it for cars. Is it just Valero branded stations or do Valero's other brands sell it as well?

Here in Stillwater, it's not even all Valero stations - just one.

As far as the government regulations, I think it's a state by state mandate. Oklahoma apparently doesn't require ethanol in the gas.

[Rick Denney]

I didn't realize somebody was still selling no ethanol gas. I assumed that the gubmint had outlawed it for cars. Is it just Valero branded stations or do Valero's other brands sell it as well?

Here in Stillwater, it's not even all Valero stations - just one.

As far as the government regulations, I think it's a state by state mandate. Oklahoma apparently doesn't require ethanol in the gas.

It depends on each regions air quality improvement program, which is part of the statewide air quality improvement program. Metropolitan areas that do not meet air quality requirements are termed "non-compliant" and must enforce the use of such additives as oxygenate. The alcohol acts as an oxygenate, and in that role it's a lot better than the alternative, which is the very toxic MBTE. But whether oxygenated fuels really make the systemic improvement claimed for them is another debate altogether.

Most rural regions do not require oxygenated fuels. And even where it is required, it will be affected by the season.

Which brings me to another issue: Vapor pressure. Summer-blend fuel has a different vapor pressure than winter-blend fuel to help prevent vapor lock and still provide clean operation. And summer-blend fuel may require different oxygenation to account for the higher incident of stagnant conditions and ozone alerts. For our daily drivers that get a fresh fuel tank every week or two, it doesn't much matter. But for vehicles used only occasionally, we may be burning winter-blend in the summer or vice-versa, and winter-blend fuel can be subject to vapor lock to a greater extent than summer-blend fuel. It's something to consider. Of course, if you pour a fuel stabilizer, such as Sta-Bil, into the tank to help the fuel last until the next use, you have turned your gasoline into gasohol.

With the GMC motorhomes, there have been reports of the vapor pressure being so low that mere road heat is enough to start boiling the fuel in the tanks (and this effect has been described in this thread, too). That can cause fuel starvation for sure. But it acts like fuel starvation--the engine does not run well when being asked to make power, but will idle smoothly. I've had that problem on my GMC from time to time, even using an electric fuel pump back by the tanks. For old cars that pull fuel from the tanks using an engine-mounted fuel pump, the slight negative pressure applied to the fuel can greatly lower it's vapor pressure and boiling point, and even moreso if the sending unit/pickup is restricted in any way.

For the unrestored Buick, it would be worth the trouble to drop the fuel tank, remove the sending unit, and inspect the interior of the tank for rust. As I said before, this can happen just sitting there because of the way the tank breathes in moisture-laden air with the changes in ambient temperature. It's a required step in keeping a really old car running reliably. Also, make sure you use Sta-Bil when you aren't going to be using the fuel in the tank for a long time. It's better, though, to give old cars reasonably frequent exercise. Cars driven frequently will survive the ages better than cars that just sit.

Rick "thinking a frame-off restoration of a GMC motorhome, while not that uncommon, is still a really big job" Denney