Horrid gas millage

ho bag · Post by **ho bag** » May 13th, 2006, 8:17 pm

Well first off its a 93 1.8l auto, $20 get maybe 120km.....Thats just wrong. It is running right and smooth but the tips are black so its running rich. I did notice a very small light miss at idle today and a low idle condition but i hear that plagues all autos.

Its not leaing fuel, everythign is air tight. I will check the plugs and compression later, wires look new but i will check the resistance as well. The according from the vaf to tb is fine..

Any idea?

solo_ryder · Post by **solo_ryder** » May 13th, 2006, 10:14 pm

There could be a few things, first off it can be your o2 sensors, but before you change those as they are abit pricey, cehck ALL vaccuum lines, u'd be suprised how bad of mileage you get with a vacuum line disconnected. Also, check your air filter and fuel filter (located under the battery)

ho bag · Post by **ho bag** » May 13th, 2006, 10:23 pm

Ill check the air filter, Fuel filter i cant really check, Woudl have to just change that but it shoudl be cheap anyway. I plan on vacume hunting tomorow but i didnt see anything off today.

Im not getting a check engine light either, It did flash once will doing 100kmph on the highway but that was it. Im thinking electrical or sensor somewhere could be fubar but with no engine code ill never find it.

solo_ryder · Post by **solo_ryder** » May 13th, 2006, 10:50 pm

ahh that could be it man, i had a CEL going when i was on the highway and I think the EGR vac was unplugged, check the soleniods behind the TB and there is 3 or 4 vac lines there.

ho bag · Post by **ho bag** » May 14th, 2006, 11:49 am

Well all vacume lines are good, nothing unpluged. PCV was cloged a little bit but that has been fixed.

Plugs and wires are marginal but ok, They will be replaced soon anyway. The tops of the pistons look like a--. Very very dirty, I will run a can of combustion chamber cleaner in there next week to clean it all up.

I could not see the egr as the battery was in the way. What is the best way to remove the egr valve and clean it? do i have to remove the battery or throttle body or anything else to get to it?

Oh and the spark plug tueb seals are gone big time, ill use some rtv to slow down that leak for now, No point it putting in new gaskets if im just building a new motor anyway.

solo_ryder · Post by **solo_ryder** » May 14th, 2006, 12:56 pm

Ok, well having dirty pistons is somewhat normal, that is just carbon buildup from all the ventcase breathing that your motor does, the best way to get at the egr is to take out the battery and hte TB, you my have to take the IM off to, while you are there change the fuel filter.

hgallegos915 · Post by **hgallegos915** » May 14th, 2006, 12:59 pm

I just fixed my richness, it was a combination of a going bad front o2 sensor and a clogged fuel filter. Yeah clogged fuel filter can cause it to run rich/... why? well because the computer detects a "lean" mixture and then in makes the car run richer however since fule filter som etimes spits normal and sometimes less than normal... it makes you run rich. At least in my case thats what it was.

PWRD_BY_HKS · Post by **PWRD_BY_HKS** » May 14th, 2006, 1:34 pm

yeah.....try fuel filter

ho bag · Post by **ho bag** » May 14th, 2006, 1:36 pm

These went just dirty pistons, there was some serious build up on them. Also the fuel filter is a good idea as well, i should consider that maintance anyway.

Is there a high flow fuel filter for our cars? also does anyone have a pic of the fuel filter? I may be able to find a oniversal high flow unit to replace mine with.

Oh and are our 02 sensors 3 wire or 4 wire? I find it easier to buy a universal sensor and solder on the right conector off the old sensor. usually saves about 50-75% ov the cost vs new oem sensors.

I can see the front sensor and it will be easy to change.....the rear i hacent even found yet.

solo_ryder · Post by **solo_ryder** » May 14th, 2006, 1:39 pm

I dont think u can use a high flow fuel filter as you really want to filter the fuel, there is a metal band that goes around the fuel filter so only the mx3 one can fit unless you modify it, but you will not see many results, as for the o2 sensor, they are 4 wire front and back. You can try to use a unvirusal ford probe 02 and splic that into your harness, that is what I did.

Here is a pic of the Fuel Filter:

hgallegos915 · Post by **hgallegos915** » May 14th, 2006, 2:07 pm

Get the mx3 fuel filter, speciallpy designed for our cars..when u blow trough it there is no resistance at all. they already are high flow, actually the aftermarket "high flow" filters are more restrictive. Stick to the mx3 one. TRUST US

ho bag · Post by **ho bag** » May 14th, 2006, 3:03 pm

Well im sure you could blow through any fuel filter witn no resistance

It does look like a perty universal fuel filter, nothing special. Difference is a generic filter will probally cost alot less then a mazda fuel filter.

I will deffently look into using the probe 4 wires o2 sensors with stock connectors. Or a ford ranger o2. There dirt cheap 4 wires sensors. I used them on my dsm and they worked perfect!

But i got a feeling none of this is causingt my issue, its just burning wayyyyy to much gas to be caused by these things. I dont think its tps cause the car runs good, maybe the coolent temp sensor is gone or the VAF is bad..

And i must say the VAF is a horrible looking setup. i cant see it doing anything but causing a restriction in the intake. I think there is a vaf delete setup right?

hgallegos915 · Post by **hgallegos915** » May 14th, 2006, 3:42 pm

well see.. i was getting 15 miles per gallon.. now i get 30 miles per gallon as soon as i replaced front o2 and fuel filter.... maybe its my tps? i doubt it.