Terrible gas mileage! 240 miles per tank!!

[lanemeyer14]

I'm only getting around 27 mpg/240 miles per tank with my 90 efi 5spd festy....something is wrong here! I'm guessing my timing is off from when I replaced the head gasket. How many miles should I be getting per tank with city driving? Should I just get a timing light and check it out? Also, I've never used a timing light, so what's the best way? Thanks in advance!

[Pu241]

For a quick and dirty:
Fire-up the engine and let it come to normal operating temp.
Ground the STI connection (while its still running)
Then mark the position of the distributor body relative to the valve cover or other reference.
Then loosen(leave then snug enough that it take a little effort to rotate the distributor) the 2 hold down bolts behind the distributor and rotate it CW or CCW just a bit (can't remember which way is advancing/retarding the timing).
You may well affect idle RPM, which can be adjusted.
When it sound better, lock the distributor bolts down, remove the ground from the STI, fill the tank and see if that made a difference.
Repeat as necessary.

[88FestivaLX]

I always fill up at 240 miles or so b/c whenever my gauge gets near half a tank it goes to empty. I know these cars are supposed to have a 10 gallon tank, but I don't trust my luck, ha

[Gforcefd]

Yeah my car says 1/4 tank but starts acting like its running out of fuel, but never takes more than 6.5 gallons to fill up.

Are you actually putting 10 gallons in to fill up completely, or are you tracking your mileage, and dividing it by what you put in your tank each time (that is more accurate). PU241 is right, your timing may be off. You may want to get a new O2 sensor, air filter, and fuel filter while your at it, they are cheap enough and help a bit. Are you running stock size tires, or honking 15's with heavy rims and wide tires?

[lanemeyer14]

I've been filling it up completely. Everything is stock too...no big wheels, etc.
I just thought I should be getting more mileage per full tank of gas. It seems like I was getting better mileage when driving my prelude around town.

[GenevaDirt]

Should be getting 40 or better on normal running 5spd.

[88FestivaLX]

I normally put about 5-5.5 gallons in when I get gas at around 220-240 miles. I just started driving it again after waiting to do the suspension (haven't had money so I put it back together so I could drive it). While it was down I did plugs, cap, rotor, O2 sensor and cleaned a bunch of stuff. Now it doesn't seem to run very good and my mileage has gone down to around 35 mpg from 43. I'm about to give up, ha. The car is so nice though that I just can't quit. And I can't afford to drive anything else.

[lanemeyer14]

Ok, I filled it up again today. Put in almost 8 gallons, and I was at 250miles. So if the tank is 10 gallons then I'm getting just over 31mpg, right? Still isn't as high as I thought it should be.

[Pu241]

Doesn't matter the size of the tank!
Just make sure you refill to the same level each time!
Tanks reported capacity is 9.9 gallons, I can get 10.3 gallons in because I always fill it up to the top of the fill tube.
But your MPG is calculated on the miles driven and fuel burned = amount of fuel needed to refill to the same level.
Even though you car is stock, you might want to drive a 10,20 or more mile run on a mile marked road (typical interstates). and check your odometer verses the marked road distance.
I usually do a 50 to hundred mile run, its more accurate!

[jglutz]

For a quick and dirty:
CW or CCW just a bit (can't remember which way is advancing/retarding the timing).

For all distributors turning opposite the rotor rotation is advance....turning in the direction of rotor rotation is retarding.

For the Festiva...while looking at the distributor from the driver's side wheel...CW = advance......CCW = retard.

If you changed the head gasket....most likeley the timing belt is out by a tooth.

http://www.fordfestiva.com/forums/sh...733#post175733

[Pu241]

jglutz,
Good catch with the head-gasket replacement, some how I missed that!
If that is the case, then moving the distributor might not be enough to get optimum timing.
I don't think the limited movement allowed in the distributor is enough to compensate for a timing belt off by a tooth or more.

Can't get your link to work.

[jglutz]

Link fixed
If turning the dist makes it better...the fix is not complete because the compression cycle will still be off by one tooth only the ignition hs been compensated.
The link should be self expanitory.

[lanemeyer14]

Thanks guys! I had so much trouble with the timing and I guess it still isn't right....guess I'll be working on it tomorrow!

[Pu241]

Thank us when its running right!
These are educated guesses based on limited information.
Hope it helps!

[SoCalZ28]

what kind of plugs did you use and what gap?