How is the gas mileage on a 71 Cutlass, 350 motor. I put $40 gas in the tank yesterday and rode about 100 miles. Now the car wont even start. Is gas mileage bad? Confused?????

 

Not sure where your going here, no gas gauge ? Anyway my 1970 Cutlass with a dead hole got 19 mpg. It was a 2 bbl.

 

Here is a good thread...
https://classicoldsmobile.com/forums...286-m-p-g.html

14-19 would be reasonable for that motor for normal lightfooted driving.
How many gallons were in your 40 bucks?
Gas gauge works or not?

 

Gas gauge not working. Thats a diff issue. $40 at $2.30/gallon. I just bought some gas and it started. This is crazy. I didnt think the gas mileage should be that bad. Is there anything I can do.

About the gas gauge. My mechanic says that I need a new sending unit. And that I shouldnt buy a sending unit without buying a new gas tank. The tank that I have is the original. He says its in bad shape. Any suggestions?

Also, there is a strong smell of gas coming from the car. Is this natural?

 

Hmm in a word no you either have a leak or she is out of tune and not burning the gas right.I have seen tanks and sending units for older cars on ebay.I am not shure if say fusicks can help but somone in here might have the right idea.

 

At worst case 17 gal of gas should have gave you at least 200 miles - 250 is more like it.
Where is the smell the worst? In the car? Towards the back? Under the hood?
If your tank is really rusty, the pickup sock or fuel filter may be clogged.
After 6 seconds of cranking, pull the air cleaner lid off, look into the primarys and open the throttle. If you see no gas squirt in fromt he accel pump, then it is a fuel issue. I am curious to know how bad the tank really is.

 

I think it is irrelevant if the gas gauge is working or not. If gas was $2.30/gallon, $40.00 would buy slightly over 17 gallons. 100 miles divided by 17 gallons is less than 6 MPG. I don't think it could far enough out of tune to get that bad of mileage. You got to have a leak somwhere or somebody stole some gas.

 

X2

 

Wow, thanks for all the input guys. As for the gas smell, it is mostly coming from under the hood. I just replaced the carbeurator a few months ago.

As for a tune-up, my mechanic says that the engine is very strong and doesnt need a rebuild. However, I had a tune-up last year. I've had the car three, going on four years and havent driven over 1000 miles.

Not sure why the fuel is disappearing. It's not getting stolen. My car stays garaged 24/7. How can I find out if there is a leak? Thats the only solution that thing that makes since at the moment.

 

Check for gas stains on your garage floor. A leak could be coming from the gas tank, gas lines, fuel pump, filter, carburator, etc.. Do you see any leaks when you fill the car up with gas (at the gas station)? Does the car smoke (I'm told white smoke may indicate a gas guzzler engine)? Could it be that carb you just replaced - how long has the problem been ongoing?

I'd sure carry a fire extinguisher with you until this problem is determined. Not a bad idea having one in the car anyway.

 

Do you know the the rearend ratio or the rpm at a certain speed? Performance modifications to the engine or trans?
Maybe it had the gear ratio changed for drag racing and it's screaming.


I would get a new tank and sending unit, that's a no brainer if your mechanic says it's bad, rusty? It's especially important if you keep it in a garage, don't want any fuel vapor surprises in there when it decides to let go if it's rusting bad.
The gas cap the correct non-vented type?, fuel vapor canister hooked up or the hose to the tank capped?
Did you pump the gas?, put the cap back on?, those are American dollars and gallons correct?

 

Dnt think it is the new carb. This is an earlier prob. The only leak I see now are oil type leaks. AND THOSE ARE NEW (I had no idea it was leaking!). I'm getting very frustrated.

I'm really confused because I put atleast 15 gallons in the tank last night. I then drove about 100 miles and parked the car. Today the car would not start. I went to the gas station and filled up my 3 gallon emergency tank and poured it into the Cutlass. It then started. I drove to the gas station to get gas, and the car only held 8 gallons. WTF!

 

I'm really confused because I put atleast 15 gallons in the tank last night. I then drove about 100 miles and parked the car. Today the car would not start. I went to the gas station and filled up my 3 gallon emergency tank and poured it into the Cutlass when I got home. It then started. I drove to the gas station to get gas, and the car only held 8 gallons. WTF! Does anybody have a clue???

 

sounds to me like your sending unit is messed up and your filters need to be checked.I call the screen in the tank a filter as it basicly is.Did you check your lines I had a car I started to smell gas though I didn't see any drops or puddles.I couldn't find the leak then driving one day I watched the gas gage as it started droping.I got home jacked the car up and found lines near the tank were shot so I did the easy fix and used gasline hose and fixed it.THe problem with gas leaks is they can start small enough to get a line wet and evaporate,that is till you step on the peddle and it squirts out.

 

The logical places to look are any of the hoses. Take a close look at the hose from the gas tank to the fuel line. Look closely at the hoses on the fuel pump and to the carb with the car running. If the car is going through this much gas, you need to get it fixed before it catches on fire. Remember gasoline evaporates so you may not see it like oil that is leaking. Take a good look on your intake manifold also. With this much of a leak I would not be driving the car until the leak is fixed.

 

nice suggestion delmont. my mechanic did say that i needed a new sending unit. i was just under my car moments ago trying to figure out if i have one or two line. "i think" i only saw one line. however, im no mechanic.

 

Most cars have vent line and the fuel line.Though the newer ones with the fuel injection have a fuel send line a fuel return line and a vent line.

 

My recommendation is to find a reputable mechanic and get this problem fixed. (If the mechanic you spoke to did not give you reasons for the poor gas mileage, i would go to someone else). This is too dangerous an issue.

You mentioned, "I'm no mechanic", then perhaps it's time to seriously consider getting a professional to find out what's causing the poor gas mileage and potential gas leak.

IMHO, don't waste any more time, especially if you suspect a gas leak.

 

I agree with Dan. Find a good mechanic that can remove the gas tank, replace the fuel sending unit, and repair the tank. POR 15 and Eastwood make kits to rebuild and coat an old gas tank. As long as it isn't rusted through these kits will make it like new. Once you put a new fuel sending unit on it your gas gauge should work. Make sure you let the mechanic know your problems and what your are hoping to fix with the service he does.

 

And keep a fire extinguisher handy