My 88 turbocoupe daily driver is getting terrible gas milage around 12mpg. The car has 4.10's, t3 turbo, ported intakes, and 65mm t/b pretty much thats it and I dont beat on it always and milage still sucks. It drives real nice and reliable but the milage is killing me also the car is a stick any ideas what to look into to improve milage?
hook a dmm up to your o2 sensor and see if its switching slow( the black wire). they have a tendency to read lean as they age.
The o2 is not too old i would say 6 months old.
Any check engine lights? Check the codes.
Nope the check engine light is not on.
Check the codes anyway, you never know.
4:10's says it buddy.
My TC is modded to the hilt and blowin 19psi on the street through a SC50 I still get 28-30 on the highway and 16 around town. I just filled up this morning, 18.7 gallons for 342 miles.
I doubt its the gears.. My 3.8 cougar didn't get that bad of mileage when it had 4.10's.
I really doubt its the gears also once in a blue moon it gets like 21mpg also I dont drive that much on the highway.
Assuming 5 speed 4.10s x .8(O/D)= 3.28 final ratio... No problem there... Hell we ran 4.30/4.56s on the street in the 60/70s WITHOUT O/D... Yea gas mileage sucked...
If you are just puttering around then that mileage is bad, but with the mods to your car I doubt thats the case... Once you are in the boost, mileage goes in the dumper...
Thats the thing even with me only seeing like 2psi on acceleration sometimes milage really stinks.
leaking injector o-rings? pretty obvious, but thats the only time my 2.3T has ever got that bad of mileage...
have you dialed in your tps with a volt meter?
Replace your Temperature sensor (TPS). I had they exact same issue, tailpipes were black and i was getting 15mpg...
heres a picture off NATO (North American Thunderbird Organization) shows sensor locations.
ummm TPS is NOT "temperature sensor"
tps is throttle position sensor my bad..
its the ECT you want then.
How much boost are you running? What injector size do you have? What is your base fuel pressure without boost?
Well injectors are not leaking.
Im running 18lbs of boost stock injectors ans stock fuel pressure.
I would say run codes and see if anything pops up. Is the orange ground wire connected to the turbo inlet housing? Try and keep the RPM's below 3K so the computer stays in closed loop. Coolant sensor for the ECU reading correct?
Mike
You might want to check your fuel pressure regulator. Pull the vacuum line off of it, if you smell gas and you shouldn't, it is a bad regulator and would cause a rich condition and bad fuel mileage. Hope this helps...Tommy