Bad MPG. What else am I missing?

[Hazwan]

I know the basics, but just making sure what else I'm missing here

I get about 15.7mpg city driving.. like a grandma. That IS bad. How do I know that my carb is bad? What else that I could do, list out even the basic shit that I probably have missed.

Also, I think I'm burning oil a little if not much. Does this effect the gas mileage by whole bunch?

[2oodoor]

For peace of mind, do a compression check first.
If the carb is dumping too much fuel you should see sooty spark plugs .
You can also check the cam timing then too because the motor will bw easy to turn while the plugs are out.

[Hazwan]

For peace of mind, do a compression check first.
If the carb is dumping too much fuel you should see sooty spark plugs .
You can also check the cam timing then too because the motor will bw easy to turn while the plugs are out.

I'll give them a check (Y)

Also, does this look worn to you?


There are no cracks or anything but I noticed slight groove to them. Same goes with the rotor.



I don't remember when was the last time they are all replaced but probably loooong time ago even before my dad gave the car to me

I know I could just replace them all (including my spark plug cables) as a preventative maintenance item(s) but I'd rather not waste money on something that still work perfectly fine.

[2oodoor]

You are still using ignition breaker points?
My roommate had a 1 gee that I drove for a long time and one thing I remember is those points being a PITA due to a worn distributor.
I also discovered that the cap and rotor need to be a matched up pair, same brand, etc. on those or it can cause problems.
If there are grooves then yes that can cause someresistance in the secondary ign, which in turn can burn up some points, cause misfires or cross fires.

EDIT, I see the reluctor wheel now, it isn't breaker points is it. I was looking at the two wires, and then what looked like an adjusting screw.

[Hazwan]

Yeah its electronic. Does the groove means anything to an electronic dizzy?

[Buzo]

That ugly fuel mileage is mostly caused by the carburetor and/or 1 (or more) bad spark plugs/wires.

So the easiest check would be to make sure all your spark plugs are firing.
Then go for that carburetor. It can be as easy as a jammed choke plate, to a need of full refurbishing.

[Hazwan]

I'll give the spark plug and wires a check.

I had the carburetor rebuilt last year and unless I did something horribly wrong, I don't see how it could be bad haha

[Dr_Snooz]

I had the carburetor rebuilt last year and unless I did something horribly wrong, I don't see how it could be bad haha

You rebuilt a Keihin? I think Keihin is Japanese for "worst carb ever."

How does the car run?

[Hazwan]

You rebuilt a Keihin? I think Keihin is Japanese for "worst carb ever."

How does the car run?

LOL mine is the simple 2 barrel stuff without the CVCC and the emission crap so I think I'm good. I think. Car runs fine except for rare stumble/hesitation when going off a speedbump. Idk why or how to explain.

Anyway I went ahead and replaced the cap, rotor and wires just because they are cheap and old. Car idles super smooth now o.O Except my tach kinda jumps every once in a while during idle. I don't see how replacing all these items would cause the tach to jump around randomly? its like idling around 750 rpm smoothly then the tach would go 1200 back to 500 then goes back to 750.

[Dr_Snooz]

I can't speak for your car, but my jumpy tach problems finally went away for good and all when I replaced the ICM. It could also be a bad coil.

[lostscotiaguy]

Wait...did someone say keihin here? (Covering my ears) LA LA LA I CAN'T HEAR YOU! Seriously though, i'd give some pointers but it looks like you've got your bases covered. I agree with Dr. Snooz on that coil, but the other thing re:carb, does it smell like it's running rich? As much as I love/hate carbs, I've been SO tempted to weld a bung into my exhaust just to hook up a F/A sensor/gauge. Now if only I had the tools, the knowledge, the money, the.....

[Hazwan]

Wait...did someone say keihin here? (Covering my ears) LA LA LA I CAN'T HEAR YOU! Seriously though, i'd give some pointers but it looks like you've got your bases covered. I agree with Dr. Snooz on that coil, but the other thing re:carb, does it smell like it's running rich? As much as I love/hate carbs, I've been SO tempted to weld a bung into my exhaust just to hook up a F/A sensor/gauge. Now if only I had the tools, the knowledge, the money, the.....

You really do hate keihin aren't you hahah

But yeah its really hard to tell from the smell since my engine burns oil and the exhaust smells like... well, oil?

[ghettogeddy]

have you tried different brands of gas or do you just use w/e is cheaper? i notice a difference in my elantra between 76 and beacon almost 5 miles per gallon

[2ndGenGuy]

I say get one of those 2000's era carbs from one of those Malaysian cars you've got over there, and make an adapter plate! You can do eeet!

[Hazwan]

I was just wondering if my brake booster is actually leaking since I could hear it hissing when the engine is running? This too would probably explain why I could never get the mixture 100% correct.

So yeah is a hissing brake booster normal?

[2ndGenGuy]

Definitely should not be hissing. I would replace it! And yes, it would explain your mixture troubles.

[2oodoor]

Make sure that isn't just the check valve hissing, the piece in between the hose and the actual body of the booster. A valve would be an easy fix.

[Hazwan]

I should add that I lose the booster function right after the engine dies too. I know its not supposed to do that and thats the check valve's function right?

I'm gonna have to give the check valve a.. check.

Also, replacing my dizzy cap, rotor and wires got me 22.5mpg of city driving, which I don't think its too bad? Help me squeeze out 3 more mpg please!!

[1GCustomAccord]

Did you check your vacuum advance?

[Hazwan]

How do I check them properly? They appear to be moving fine but idk if they actually works properly under vacuum.

[2geeSEi]

Does your advance have one or two hoses going to it?

[Hazwan]

Just one hose.

[Buzo]

...
Also, replacing my dizzy cap, rotor and wires got me 22.5mpg of city driving, which I don't think its too bad? Help me squeeze out 3 more mpg please!!

Good to hear that it improved from 15 to 22!

How is your choke working in general?

The choke is usually needed for the cold mornings only, but during the day we don't need that much fuel to restart the car.

An easy way to check if you have choke problems is if your car restarts very rough and you need to accelerate it to control it.

A restart means being driven for some time, then stop the car and attempt to restart it into the next 5-30 minutes.

[2oodoor]

That does sound like a check valve leak, but I would still check the inside of the car side of the booster to see if that is hissing.

You can check the overall basic function of the advance system by putting a timing light on the marks (crank pulley or flywheel) and watch the marks move out of sight as you raise the rpm.
If you have a advancing timing light you can zero it out and match the light to the TDC mark and the display will read out the amount of advance.
I don't know if the 1gen has vaccuum advance on at idle like the 3rd gen or not??
If it does then you can pull the hose on the dizzy at idle and the rpm should change if not may even stall out the engine. That would mean it is working.

[2geeSEi]

If the advance has only one hose, it will not be on at idle. The easiest way to check it is to take off the hose and put a hand vacuum pump on it. Start the car and watch the timing when you put vacuum on it. The timing should advance and should hold the vacuum.