83camaroMN

I want to know what you people that have the 82-84 2.8L carb. get for gas millage.

Only reason I ask is because today I put a little over $5 at $2.65 a gallon (so about 2 gallons) in my camaro and I only drove 8 miles and it was gone. What could cause me to get this bad of gas millage, It had a recent full tune up even had the carburetor fixed, and I was easy on the gas well kind of.

kukerdan

iTrader: (1)

check ur sensors,
cat,
air filters,
plugs/wires/cap/rotor
change oil, maybe switch to synthetic
try adding a small amount, 3 oz , of acetone to your gas

83camaroMN

Air filter is new put in when carb. was fixed, It has brand new plugs and wires with less then 5k on them, I just changed the oil a few weeks ago but I have to add a quart every 300 miles because it leaks when it sits and burns when it moves. My exhaust is original and this winter I was thinking of gutting the cat. out so that might help.

1 question if the cap/rotor is bad would it cause the car to rapidly jump RPM'S when going down the hyw?

2_point8_boy

4 MPG is horrible, even for a carb'd vehicle.

There are a lot of things to check, one would obviously be to take a look at your plugs, what do they look like?

Other things include the actual build on the carb, who rebuilt it. If you are only getting 4MPG, there is something wrong with that carb, there's a power valve leaking, or a needle and seat/float that's not adjusted right. As long as you have a good tune on the carb, you should be seeing a minimum of 15mpg, the rest of the sensors and stuff on your car are there to improve milage and emissions from that point.

If you completely disconnect the computer and have absolutly nothing else on the engine working, you should still have 15mpg.

Also check for the obvious fuel leak at the tank, pump, and carb inlet.

83camaroMN

HAHA yeah it is bad, The carb. was done by murgic's automotive and he changed a few things on the carb but I am sure he did it right besides it is getting a little better then what it did before. The plugs and wires were put in last year and have around 4,000-5,000 miles on them and I also pulled them out a few mounths ago and look fine.

83camaroMN

It was the cap and rotor that was giving me very bad gas milage.
It still gets bad gas milage but way better then what I was before, now I think I am getting at least 15 MPG around town and I was getting around 8 MPG.

kukerdan

iTrader: (1)

shotty spark is def somthing that causes bad mileage.

You saw a big increase with the cap and rotor...

How are your wires looking?
what about the plugs?

Might as well go delco rapid fire,
and some nice fat wires.. that will help do.

Not to familiar with the carb models,, I dont think you
can put a coil in like msd blaster..
But you could probably put a nice mallory dual point distributor.
or blaster 2 universal set up..

With that you might be able to increase the gap on your plug
(or go with bigger gap plug)

hotter/longer/bigger/less resisted spark
will result in more power (cause more is getting burned)
better mileage, and better emissions.

91chevywt

My first thought would be a fuel leak, since i dont think that motor could even burn enough fuel to make 4 mpg...you would probably see black smoke and would be lacking power. If it were mine, I would check fuel lines especially since its old..when the carb was pulled a line could have been cracked or even not tight. If nothing is visible or can be smelled, Bring it back to the shop and the tech might find a mistake. After all, this crappy mileage didnt start til after a major component of the fuel system was played with

Cratemaster

glad you got the gas thing fixed, 20MPG highway is good for my '84 2.8 so I think you're were you should be with you mpg, but...about that rpm jump on the hwy, you said you're transmission slips badly in your car description, Is it an automatic? I assume you've checked your tranny fluid level, so either it's trying to downshift then it decides not to and just remains out of gear for a second, thus allowing for a jump in RPM, or it's totally slipping, in which case I'd take it to a transmission shop were they will probably confirm that it needs a rebuild. (quite expensive and in your description your planning on junking it, so I wouldn't bother)

Cratemaster

[quote=2_point8_boy;3481956]4 MPG is horrible, even for a carb'd vehicle.


I'm not questioning your comment at all, I was just was wondering why fuel injection is so much more efficient than carburetion, if the amount of gasoline that gets drawn into a carb'd engine is solely dependent on how much air is allowed in, wouldn't that allow for a near perfect stoichiometric mixture of fuel and air (with the exception of the limits and inadequacies of man-made equipment) and therefore, only allow the engine to literally "sip" fuel, with EFI, the combination of fuel and air is artificially calculated and "added" or forced into the engine, and if any calculations of the computer are off, than inefficiency is the result.

91chevywt

Carbureators can get good mileage, but theyll never be as good as fuel injection. The only thing that will hinder fuel mileage is if a sensor or circuit in the engine management system is reading improperly...computers dont mess up. Just remember, garbage data in, garbage data out. In my opinion, the best advantage fuel injection has is that it will spray directly behind the intake valve..eliminating puddling of fuel in the intake manifold which happens all the time with a carbeureted engine. The fuel will be more finely atomized than a carbuerator will ever be able to do. Plus, if you look at dynomometer testing between fuel injection and a carb the power band will be much wider, but peak hp will be almost the same. Fuel injection may be harder to set up while performing modifications, but youl learn that its way better in the long run.

Cratemaster

Roger that, that makes a lot of sense, I'm just being curious.