New owner MPG tips

[crusher773]

Hey guys new festiva owner here. I have had mine about 2 weeks and am getting that same crappy mileage. 28-29 somewhere in there. Its a '93 GL EFI. I was having trouble with it not wanting to start when warm and to get it to start I would have to hold it wide open and it would try and fire a bunch of times and then finally it would start but would barely run and then it would finally clean out with a big puff of exhaust. I changed the ignition control module and the coolant temp sensor and that seems to have solved the not starting when warm issue and my check engine light is also not coming on anymore. My question is will this likely fix my mileage problem too as from what my Haynes book shows that sensor was probably making the emissions system not work right. So my other question is what little tricks are you guys using to get these super awesome 40, 45+ miles per gallon out of yours. Every little bit helps. Thanks.

[getnpsi]

Yes, emissions and mileage are usually hand in hand, making everything how it should be will reward you in fuel savings at the same time on an efi car.

A fresh o2 sensor will definately help. It could have been messed up from running rich too long. If you are in a colder part of the country look into getting a real mazda thermostat, the thread sticky that says "for those with hardly any heat," buy that part and install it. Not getting up to temps can make a car very dirty too.

If you are very mechanically inclined look into wiring up a modern HEATED o2 sensor, one off a 1990s ford thunderbird or similar. I'm not sure how a 4 wire would hook up, as one of the wires goes back to the ECU to let it know the heater circuit is working like on my dodge. Skip those and find a 3, it will cost less anyway. This will let your car go into closed loop quicker provided that all the other sensors are in good working order. Plenty of members still get 40mpg+ with their regular 1 wire sensor but if you are going to change it anyway it can't hurt to do an upgrade.

[crusher773]

I read through that thread. According to those pics my thermostat might be OK because thats about where mine sets at temp wise. I do get pretty good heat too. I was planning on going ahead and changing the O2 sensor to see if that helps too. I didn't look real close yet but it looked like it was right on the front of the motor right off the exhaust. I just really want to get at least 40+MPG. So if I get a 3 wire where do all the wires go to?

[getnpsi]

on a 3 wire, one is the data wire spliced into the one you have going back to your harness, and the other two, one is a ground and the other is a hot with ignition wire. One more thing cut the wire after the sensor, as the actual wires on the o2 are sheilded wire. My suggestion is to snip off a pigtail from a donor car and either take its sensor too or buy a new one that matches at your auto store.

http://jaguar.professional.org/O2/index.php

[Darlo]

I guess I got really lucky because I got 46-50 mpg right from day one (That is in the summer, in the winter with my winter tires on I "only" get 42-46mpg).

I drive very conservatively though, and rarely exceed 50-55mph (80-90kmh).

I did notice a small increase in mpg with a lucas additive. For me it was barely worth it, but for you it may clean some stuff up? (That is from my (not so) vast knowledge of all things mechanical, lol)

Try a couple tanks driving REALLY nice (no speeding, fast starts etc) and then we can see where you stand.

Here is the distribution of fuel economy for 55 festivas (note some are auto) (Also note that mine is 3rd highest, haha)
http://www.fuelly.com/car/ford/festi...20l4/hatchback

[crusher773]

I've been being pretty easy on her I run about 60 t0 63 or so out on the highway. Most of my driving is highway. I always go easy with starts on it. I've put some lucas in it this tank as well to clean everything. Put some oil additive on the oil change too. How much of a difference does this O2 sensor upgrade and effect it? So just 1 to where it was already going 1 to a ground and then wire the other into the ignition?

[WmWatt]

agree, engine efficiency is key. a working O2 sensor and ignition control module ensure all the fuel is burned. cleaned and gapped spark plugs and clean and well connected ignition wires also help. another thing is minimal running friction - inflated tires, greased bearings, brakes releasing. don't load the vehicle up with extra weight and wind resistance. go easy on the gas pedal, the smoothest ride is the most fuel efficient ride. drive to save fuel, not to save time. plan the route to avoid climbing hills. avoid strong head winds. in winter snow tires help reduce slippage.

[ericsmith32]

I'd say after you got rid of the CEL your mpg's should of went up. With your driving habits you should be able to break 40 easy. I wouldn't count on anything after that. All depends on the Festiva. One of my dads gets 45 the other 42-43. Right now I'd love to see 28-29 out of my Aspire.. I think maybe 18mpg on this tank. But I think the gas tanks leaking.

[getnpsi]

That's right. I would make sure the black wire is the signal wire so it depends on what you are taking it from. I have yet to do a 3 wire conversion on a festiva. After checking out that site that i used for a different ford, personally id look for a smaller import car that also uses a 3 wire in case you don't have a lot of room inside the manifold (some poke into exhaust stream more than others) I checked around more and 1986 escort is a car that has what we'd want, probably better than the larger cars.