fuel mileage problems

[Movin]

Hi there! Were you able to increase your mpg?

I have a 1990 fuel injected blueberry festiva, and just got my mpg after a tune up (plugs, wires, cap/rotor, oil/filter) And im still only getting 30mpg. Most of my driving was 60mph on the freeway.
Is there a way to check the airflow meter, or should I just replace it? Any help would be appreciated! I'm just so surprised at how low it was after a tuneup. I should atleast get 35, right?

I hope I'm not invading your thread, just hoping you made some headway on your issues
-Mike

Hi Blueberry, I have the same car, my red one and 35 is about what I get towing ATV , You would really have to work some to get down to 30.

[fliermike_12]

Ya, it's strange... We've had many festiva's and all were 35+. Should I check the timing? The o2 sensor? Vacuum leaks? I just changed the pcv valve too.

[monkeykiller1996]

actually i think it was the severe cold mixed with the ethanol in the newer gasses that was doing it now since it warmed up in the mid to low 40's im getting about 35ish mpg also i replaced the broken vacuum solenoid on the firewall that helped to but the carb likes above freezing :tm:

[monkeykiller1996]

oh i also replace the three fusible links under the hood with actual fuses and put a new muffler on it since i originally posted ,I'm not going to do much more bc its going to soon have the 1.8 in it

[Movin]

That 1.8 will be awesome, you can fine tune air flow, rolling resistance, exhaust..things that will work with the 1.8 too.

[monkeykiller1996]

so either me or the fuelly app is wrong but it says i'm averaging 54mpg altho it is mostly highway miles from 55-65mph but sill thats some crazy mileage

[fliermike_12]

oh i also replace the three fusible links under the hood with actual fuses and put a new muffler on it since i originally posted ,I'm not going to do much more bc its going to soon have the 1.8 in it

Would you mind explaining the process of replacing the fusible links with actual fuses? Is there a way to test the vacuum solenoid. Would replacing a really bad muffler/exhaust system help the MPG any, like if there was no muffler would it affect the MPG?
.
Congrats on your soon to be 1.8 fester! My dad had one years back, he competed for fastest in his class quite often autocrossing, I will never forget that car.

[monkeykiller1996]

if you want i can post pictures of how to change the fusible links to fuses and yes there are ways to test the vacuum solenoid and i don't thing a muffler would actually help mpg or hurt it unless it was too small and causing a restriction

[fliermike_12]

Man, thanks so much for your help. This festiva has been driven on gravel roads for the past 3 or 4 years without much maintenance. Next things needed to be done is front and rear struts (BAD), the rack and pinion is very bad. Thanks to a very nice person on this forum (thanks so much, it means so much!) , i'll be getting a rack and pinion and backseat, speaker mounts...

But what is concerning me the most is getting that very low 30mpg. Advance timing maybe?
Again, thanks so much for your responses!

[Movin]

Cheap fun stuff that could lead to turning you into a megasquirt computer nerd. Get the best stock O2 , a denso , and a cheap harbor freight digital multimeter , mount the meter where you can watch it. You can watch the numbers your computer is getting in almost real time!

I use NGK and run the timing hot depending on fuel and altitude.

You have a nice long shop ? Use a heavy fish scale and "tow" your car with it across the shop. Mark the weight it takes to tow the car.

Find a nice long steep grade good for at least 70 mph. Start down hill from the top at 50 mph in neutral . Pick a landmark toward the bottom and record
your speed there.

Don't change more than one thing at a time on rolling resistance or aerodynamic improvements so that you know what did it !

So, here is 3 ways to play that will not mess with a 1.8 later, and will give you a better starting platform.

[needragr]

if you want i can post pictures of how to change the fusible links to fuses and yes there are ways to test the vacuum solenoid and i don't thing a muffler would actually help mpg or hurt it unless it was too small and causing a restriction

Monkey, I know this thread is a bit old but if your offer is is still good Im sure I as well as other would benefit from those images/explanations.
After bringing my 89 carby back in terms of maintenance it is still only getting 30 mpg so I am going thru the same troubleshooting effort

[TominMO]

Monkey, I know this thread is a bit old but if your offer is is still good Im sure I as well as other would benefit from those images/explanations.
After bringing my 89 carby back in terms of maintenance it is still only getting 30 mpg so I am going thru the same troubleshooting effort

30 mpg might be fairly normal for carby, if you are doing a lot of city driving and have a heavy foot. We need to know your driving habits and route, city or hwy.

First thing I'd do is make sure all wheels are rolling freely, esp. on the rear; the brake adjusting arm tends to get rusty and might be causing the brakes to drag. Once that's dealt with (if necessary), then I'd turn to engine stuff.

Remember that you have a 4-speed, so no overdrive gear for the hwy. You can help this slightly by going to 155/80-13 tires, since the taller tire gives you taller gearing, maybe 5% or so.

But really the best way to get good mileage is to drive like your granny. Moderate acceleration, don't wind it too high, keep hwy speed down to 55-60ish.

I did an experiment where I drove the city streets with hypermiling techniques, and got 50 mpg in the city, no hwy at all.

So to sum up:
check for drag
taller but light/skinny tires
drive like there is an egg under your right foot.

Keep us posted.

[needragr]

So, right, a bit of background is in order.
Bought this 89L for $400 as 1st car for my 16 daughter. Had already been upgraded to a 5 speed but it didn't look like maintenance had been a priority & there was a handful of "fix's" that needed to be um..addressed.
At about the same time an Aspire pop'ed up, running driving but UGLY! $75.00!! So I bought it & started accumulating new bits to swap the entire suspension. It already had Miata daisy's on it too, Bonus! I did the seat swap and stored the entire Aspire drive train for a rainy day. It now has new Rio struts & had new brakes (w/aspire booster) all round. The Carb was F'ed so rebuilt that & fixed the coolant senor issues making the fan run when key on.
I started driving it mostly around town & ran across yet another Festy FS, an 89LX with blown motor VERY nice car stripped it of all the LX bits sold the body w/5 speed for what I paid for it.
It seems like Ive pulled off and tested or replace damn near everything on the car including using the 3 exhausts to fab 1 good one with like new cat, resonator & muffler.
So now I have a pretty nice looking decent running & driving little carby
The Daisys had near new Falkens in 175/65-14 so that's what Ive been running. The speedo off is off but not by too much.
Not really being sure how healthy the eng. or trans was Ive been sort of babying it no wrapping out revs, no jackrabbit starts.
Slow is smooth & smooth is fast.
A few oil changes including a Seafoam treatment. It seems to burn a qt. every 250 mi or so. Ive yet to do a valve adjustment on it though.
Ive been driving it about 70/30 hwy city.
Im wondering if it may have a bad O2 sensor & running in open loop mode? With all this I though I should be nearer 40 mpg ?

[WmWatt]

Did you check the compression yet? You didn't say how many miles are on the engine but that it does burn oil. I have a vacuum guage and like to hook that up to the top hose on the distributor advance to see how the engine is breathing. My car has the original O2 sensor and converter on it. We have emissions testing and the only thing I had to do was clean the EGR valve when the NOx was getting too high. I find it helps to clean and gap the plugs, wipe down the iginition components, and spray in carb cleaner once a year - minor tuneup.

[needragr]

Hard to tell how many miles are on it since the L cluster was swapped for LX tacho unit. I had intended to do a Comp & leakdown test after doing another seafoam flush to hopefully clean out any carbon deposits.
Driving it this morn in to work (50mi hwy) I noticed its gonna need a Water Pump so I get to to a minor overhaul soon WP, Timing Belt front main seal, valves adj & perhaps replace a lifter or two.