milage

[Jacob]

So the check engine light came on and I had a book that I read how to check what it was telling me and it said oxygen sensor so I replaced it and reset everything. the milage has been dropping for awhile and when I read the book it said that it could cause low milage because its not reading right and it could miscalculate how much and what not, but not the check engine light still comes on, (it never quit) so when I did the test again thinking there might be another code or something it didn't show anything all it shows is when the check engine light flashes it doesn't flash it just stays on with all the lights, and the milage is getting terrible, I once got 4 weeks on a tank now it only lasts about a week I love the car and would like it to run perfect again

thanks for the help,
Jacob

[fujioko]

hi Jacob,

What year is your car?

Do you remember the code number?


What brand O2 sensor did you install?

Jim

[Jacob]

twas a bosch sensor where u crimp on the wire,
its a 1991 ford festiva 1.4 its fuel injection
code 15
and I put the same sensor in as last time I got 3 years out of it with a 1 year limited warranty just like last one so its lasting longer than warranty, that's good right?

[Chobobulous]

I used a denso o2 sensor and man oh man, my car drove like it was 10 years younger. So much pep.

[Jacob]

the check engine light comes on after it has been running for a couple of minutes, but when I run the test it just stays lit, is there a code for that that I don't understand?
and would brand realy make or break the milage like that if the previous one worked just fine?

[Movin]

Check your intake to air meter connections for possible air leaks. Follow the smaller hoses out and down too.

You can test code 15 by using a dvom on the crimp connector. It should go from under .55 volts to over .55
volts by gunning the engine. See if you can make it go from .1 to .9 after it warms up some. During normal
driving if your voltage quits oscillating above and below .55 volts a lean code 15 (below) or a 17 code rich (above)
will log into memory and turn your favorite light on!

If your fuel filter restricts fuel flow at certain times this could set code 15 as well. Just think about things like air
leaks and fuel that could possibly make it go lean for a bit at certain times and you will figure it out. What were
you doing when the light turned on? Loose motor mounts letting the engine move and pull air from a loose connection?
Bad connection on the AFS ? wiggle it while holding rpm steady and listen for change? air and electrical connections.
Check inside your AFS..does the gate have a sticky spot? Check the grounds on your engine, maybe bad grounds
are giving the ECM bad information. Use what you know about this and some common sense and you should be able
to narrow the list down a lot, test those things and your golden!

[fujioko]

Hi jacob,

A code 15 indicates the O2 sensor is detecting the engine is running lean. Sometimes it can be a bad O2 sensor but often you will find the problem is something like a vacuum leak. Is your idling higher than usual?

Anyway when the car runs too lean the gas mileage will drop off and can cause potential engine damage.

I don't think the problem is the O2 sensor, but Denso is a the best brand for the Festiva, I have had very good results in the past.

Check for vacuum leaks when you get a chance.

jim

[Jacob]

ok I will give that a shot tomorrow after I get off of work, to answer your question, A while back I was having problems with it dying a lot and finaly figured out it was the crank shaft position sensor which was in the distributor, I replaced that and everything was good, it ran for about a month before the check engine light came on again and I tested it it said 15 and I was unprepared for it, so it took me a while (not sure specific before I started to work) I changed the o2 sensor here about 2 weeks ago and it idled a little more constant but it wasn't bad to begin with so I thought yep that worked good, but the light was still coming on and so after I realized the milage had gone down significantly I decided to ask help from the only group of people who shared my love of the car (some people come up with some clever jokes about it too, kinda funny on occasion)

Thanks again for the help

[WmWatt]

Can't remember if you have to clear the codes.
Maybe check that?

[Jacob]

well I started working this morning and checked everything that didn't require a lot of tools for the start, and I ended up with the fuses, there was one missing entirely, on the left side it was labeled engine, not that it was not just blown it did not exist, And after I put the 10A in I was like weird, I should try it out, and I started it and then ran it for a while, and the light never came on, I ran it around town and it felt like it responded to the throttle better, so I looked into my book and it does not tell me what its for, do you know what its for? cause the engine was running just fine without it so I don't fully understand why it would not matter.

So im on to another smaller thing that I would like to work on, the dome light is broken and I bought this LED strip light blue and it just had the wire and I unplugged the things from the dome light and put the wires in they did work, so I tried some things to hold the conection so I wouldn't half to hold it there, and now I cannot get it to come on at all and I know the fuse is good I know it once worked and idk where to go now?

[Movin]

Test it with a test light, easiest way.

[DriverOne]

Re: milage

So I'm on to another smaller thing that I would like to work on, the dome light is broken. I bought this blue LED strip light. It just had the wire. I unplugged the [connector] from the dome light and put the wires in. They did work, so I tried some things to hold the connection so I wouldn't have to hold it there. Now I cannot get it to come on at all, and I know the fuse is good. I know it once worked and idk where to go now!

It could be that you shorted out the LED strip. They're super sensitive, and require a solid connection. The easiest way to find out if it's still working is to touch the wires to a 9v battery (or your car battery) to see if they light up. Good luck.

[Jacob]

cool thanks