Hello all, I will openly admit that I know just about nothing when it comes to cars, I've been driving my 84 GS 12-A, for the last 5-6 months thinking 140-150 miles on a full tank was normal... apparently I got majorly lost in translation at some point and this is far from normal... I searched a bit around the forum first and didnt really see too many realevant topics, but yah I need help ;-; Where do I even begin lol, my friend is pretty good with cars but I dont think he knows rotary's too well ^^; but any help would be majorly appreciated.

 

I'd say it's running a tad rich. I just went 280 miles on a tank, and I have a SP 12A in my '83.
Before we can give you any real advice, we need to know what mods, if any, have been done to your car.
Poor fuel mileage can be caused by many things, from a poorly tuned carb, improper timing, faulty ignition, plugged exhaust, dragging brakes, or even too low air pressure in your tires. The list is just too long to mention every possible issue, and you could be suffering from any or all of them.

 

No mods as far as I know, its got 98k Miles on the engine but other than that its still stock lol.

 

How long has it been since you gave it a full tune-up? Plugs, wires, air filter, check/reset timing, cap and rotor checked/replaced.
How does it run? Pull hard to 6K, or bog out before that? Stock cats still on it, and air pump hooked up ( I know you list CA as your location, means nothing to me)
You could have a car in need of a good tune up, or it could have the exhaust about plugged up.

 

I have a stock 82 GSL with a custom exhaust and I get between 350-400 before fill ups. I would say something is definately wrong. On top of what Wulff listed, do you carry lots of stuff around in the car? Are there any large clouds that come out the exhaust or is your "overheat exhaust" light always on?

 

lol man I feel so clueless ^^; umm well I just got the car at like 97k miles so I should go get it a tuneup, How much does a general tune up cost? And about the Rpm's, My car is an Automatic ( I know I know shame shame ) but it has absolutely no prob reving to 6k, I've redlined it several times on the freeway. I don't ever carry much in my car, the only light thats ever on is the damn "Brake" light lol but thats broken, and my engine runs cold as ice lol and continuously tells me to add coolant... but thats always full o.o; as for the exhaust I havent checked for a huge black cloud but I've never seen one spout from my car in the time I've been driving it.

 

With it being an auto, it brings up a couple possibities. Does it actually shift into O/D? Does the trans slip? If the trans fluid looks dark, change it. Auto O/D trans cannot take a joke, and see nothing funny about dirty fluid.
Full tune up, with all the parts I mentioned before, along with oil & filter (engine and trans) will cost around $100-150 if you do the work, as much as $500-700 if you take it to a shop.
$100 may sound like a lot of money, but it will pay for itself in just a few tanks of fuel if it helps to make it run better.

 

I changed the oil filter and oil when I got the car, Its running synthetic oil but other than that I havent done any work to it :/. It goes into O/D just fine at pretty much any rpm lol, and I havent checked the Trans fluid I'll do that at break lol.

 

Ahhhh! Dont put synthetic in a vehicle with over 60,000mi... it'll eat your seals and cause a leak... not to mention rotaries dont really like synthetic. Use regular 10w30.

 

shut up.


dont listen to him, its fine. DONT TURN THIS INTO a OIL THREAD there are enough of them.

 

WOW, I haven't heard this one in years.


Like has been said, let's not debate the oil here, it won't help the original poster solve his fuel consumption issue.

 

I think that he needs to find out why the engine runs cold as ice....
Probably keeping it running rich all the time

is it really running cold or is the gauge/sensor toast?
You get heat from the heater?
check that thermostat etc....

 

Good catch. I might have seen that, had it it not been added after I read the post....

Yes, an engine that is running too cool, will indeed consume more fuel.

 

lol sorry bout that, I have to edit my posts because I cant fully get out what I need to in each response lol I'm at work and my boss likes to check my desktop for internet windows lol.

 

and about the engine heat guage it might be broken now that I think of it, I've never seen it go past the cold area, or move for that matter lol, but I do get heat when I turn on the heater.

 

Do you drive alot in the city or are you all highway miles. My gas milage sucks around town but greatly increases on the highway.

 

That cool running sounds funny, either the temp gauge is broken (unlikely) or the thermostat is stuck open or has been removed (more likely). The engine needs to get up to operating temperature to run efficiently, otherwise gas mileage will not be good.

All the suggestions about doing the routine maintenance listed above are absolutely necessary if you haven't already done these things.

Also, my biggest problem with decreased gas mileage in my stock GSLs has always been vacuum leaks. Even a small vacuum leak can cut big time into gas mileage and performance, dropping the usual stock mpg from 24 down to below 16 in a hurry. Also the car will be sluggish, which might be why you are having to push it into the rev buzzer zone to get up to speed on the highway.

Good luck, sound like you, or a friend or a paid mechanic is going to have to get busy on your car!

Ray

 

you already changed the oil and filter

now change your trans and diff fluid

idle your car for 10-15 minutes and look under the car at the cat. If it's glowing red hot, you're running ritch and dumping fuel into the exhaust

change your plugs with NGK BR8EQ's

change your wires

nothing on these cars is hard to do. If you take it to a mechanic for a tuneup, you're either:

a) rich (very unlikely, why would you be daily driving a FB if you were loaded?)
b) lazy

 

I'm going to check my cats later tonight, my temperature gauge DOES work it just doesnt go past the halfway mark lol, and YES my car is sluggish, according to my friend anyway, he's big on rx's but not a mechanic so if it is a Vaccum leak where would I start on fixing that?

 

Your temp gauge should not go past 1/4, when mine gets to 1/2, I start worrying because from there, if there is a cooling problem, they can quickly go to hot. By that time, there is often engine damage.

 

ok so I'm fine on engine temperature then, no wonder I didnt notice it move much lol. (God I'm sorry all I'm just pathetic when it comes to autos. )

 

No need to apologize, we all started somewhere. Ask intelligent questions, with as many revelant details as possible, we will provide answers as best we can.

 

I concur with trochoid, and everything you need to do is explained in here somewhere, its made many of us into reasonable and in some cases very good mechanics.

Use the search button above just put in the details of your request ie "Rats Nest Removal" I used that one as I'm guessing its a large part of your problem, also search 2GDFIS it is easy and was worth mpg as well as smoother acceleration and idle for $20 or so.

PS use Synthetics in your trans and diff, I change all mine to Synthetic Oils throughout and notice a sizable improvement in both power and economy.

 

On a further note, I'm not sure if this is truely realevant to the OP but I'm going to state it anyway, when I floor it, and push into second ( maybe third ) gear it makes this strange "turbo-esque" type noise, definately not a turbo, but it sounds similar to. I'm not sure if thats normal or not but I figured I'd mention it, I'm going to get a compression test this wednesday so I dunno, I'm hoping I can find out what it is.

 

Ok, here is where I would start. Full tune up, plugs, cap, rotor and wires. Pull the tranny dip stick smell it and look at it. If the fluid is dark or smells burnt, take it to a shop and have it changed. Check the exhaust system, does the exhaust pressure at the tailpipe feel weak, cats may be plugged. Check/replace all of your vacuum hoses, the noise you hear may be a vacuum or exhaust leak.

Check your brakes, sometimes the calipers and wheel cylinders stick, causing the brakes to drag.