hey guys, recently got my car back from yoshiya's shop... its an 87 na sport with an s5 t2 swap... only the motor, fuel pump and motor's electrical are s5 t2... the rest is s4 na... i drove it around and noticed horrible gas mileage... and now i changed the oil, and now im getting about 20 miles for a qtr of the tank... i remember yoshiya saying he didnt connect the o2 sensor, could this be the reason behind the bad fuel mileage? also i noticed that i got fuel in my oil... well a smell of fuel coming from the oil filler neck... my old motor had bad oil seals, and i dont recall draining the oil from the oil cooler... is the gas in the oil gunna be bad for my engine? no smoke as of yet, hope its just leftover from the last engine, and not another blown oil seal... anyways, if i connect the o2 back up it should be good right? wat about aftermarket fuel controllers?

 

If that's true, im not sure your car would run at all... thats pretty damn rich lol. Sure you dont have a fuel leak somewhere?

The o2 sensor wouldnt effect it that much.

edit: look at my post count

 

install the 02 sensor. CHECK/replace plugs and wires, make sure your injectors aren't leaking, make sure your Pulsation dampener is intact, make sure all your fuel lines have clamps, I don't know what else.

 

So a shop gave you your car back without the O2 sensor hooked up, an abnormally massive fuel consumption problem, and gas in the oil(blown oil control rings I think)?????????????

 

WRONG.
If you do significant highway driving, you're losing anywhere from 3 to as much as 10mpg!


I think your post count sucks.


-Ted

 

after i replaced my o2 sensor, started running 87 octane, started premixing, replaced plus/ wires, installed cone filter/heat shield.... i climbed from 10mpg to about 14-15 mpg city. about 18-19 mpg highway. i still need to buy new fuel injectors some day down the road.

 

ok well i dont think its blown oil rings because im not getting smoke... and no smell or sign of oil leakeage anywhere... i think its just from the last engine... i did the swap, but yoshiya did the wiring.

the o2 is there, but the wire is not connected... and i do tons of highway, prob bour 400 miles a week on highway alone... thats only weekdays haha...

ummm, injectors dont leak externally although i dont know bout internally but i had them cleaned at RC injectors before they were reinstalled and they said they were perfect.

also the shop gave me new plugs and new wires... ima do the o2 this week/weekend, i'll keep u guyz updated

 

Arent O2 sensors picky about voltage? I have an O2 sensor in place but the wire where it goes into the housing has wiggled back and forth so much its hanging on by threads. Wouldnt you think this would cause bad readings or non function? Sorry to semi hijack

 

Ncross: you should be running 91 octane or better on the turbo motor or you'll detonate under boost.

OP: PLUG THAT O2 SENSOR in today!!!

 

lol i wish i could plug it in today, not much labor but i work full time and am a full time college student so im friggen exhausted by the time im home LOL, so it shall wait till the weekend...

 

You have to wait till the weekend to pop the hood and plug in a connector?

 

ok
Well, it did say 787.

I didnt notice much of a difference when I had no o2 sensor, I dont do a whole lot of highway driving though.

 

it's a plug!! you can pick your nose and still have plenty of time to plug in the O2 sensor before you get to your front door.

 

uhh.. my car is na... Mazda even recommends that you use 87 octane. on a 13b.

 

I get around 22-24mpg highway.

Take a look at this. Hopfully it helps you out.
http://howto.globalvicinity.com/gv_w...=164&co=1&vi=1

 

380-400 miles a tank? Driving where and what car?

 

It's possible with almost all highway / freeway driving.
The key is to just fire the primaries only and keep the secondaries off - this right under 4kRPM.


-Ted

 

Guess thats another plug with a standalone or rtek ecu. Adjust the secondaries on long easy interstate drives so they stay off and save fuel.

 

I do about 50/50 driving. Half on highway and half on main roads. I don't drive in the city except for possibly the one day of the week.

I have a 88 N/A with only external upgrades.

 

haha, i havnt had time to update, i gotta wait till the weekend cause its cut at the ecu side, not the engine side... so i gotta pull off the side panels, carpet, and kick panel... plus i wanna work with my alarm while im at it, cause its right next to the ecu... mileage sucks for turbos... LOL

 

i forgot to ask... does not having emissions effect the gas mileage?

 

probably but im not sure how. id imagine slightly negatively, but maybe not enough to matter much

 

ya. im getting 12 on a streetported S5 T2 engine with an S4 turbo w\ ported wastegate.....
but thats gonna go up once my injector is fixed..... its a bit sticky.

 

and has anyone here tried acetone? just curious....

 

I just put new plugs in 90 vert, n/a, drove 112 miles, full tank to start, freeway only, 75-80 in 5th gear. Gas at my stop was $3.189 a gallon, took $14.25 to top off. Do the math. 112 divided by 4.468 gallons, just over 25 mpg. Just hit 160 thousand miles on engine. Acetone-why? Working OMP, TPS ****, CAS dead on, no vacuum leaks, all emissions still intact and functioning, and it idles at 750 steady when warm. And I drive it every single day at over 100 mph to keep her happy. Any questions? Not bragging, just listened to some guys in Hawaii, Rohnert Park, Canada, Rocklin, just to name a few, and if it is working correctly---------!