Bad Gas Mileage 89 900 turbo need help!

[tony565565]

i live in arizona, my 900 turbo is getting terrible gas mileage. 15city/24hwy. whats causing this? i have heard of people with the same exact turbo car getting 21city/33hwy. also when i put $5 of gas in tank the guage doesnt even move it stays on empty. gas is 1.76 currently. my old 85 volvo would move to a 1/4 tank with five bucks of gas. what could be the problem? i tried new plugs, 36psi in tires, new air filter.

[Saab 16s Stubby]

Originally Posted by tony565565

i live in arizona, my 900 turbo is getting terrible gas mileage. 15city/24hwy. whats causing this? i have heard of people with the same exact turbo car getting 21city/33hwy. also when i put $5 of gas in tank the guage doesnt even move it stays on empty. gas is 1.76 currently. my old 85 volvo would move to a 1/4 tank with five bucks of gas. what could be the problem? i tried new plugs, 36psi in tires, new air filter.

How are you calculating the 15/24. Normally I fill the tank and reset the trip, run it to the low fuel light and then refill and calculate the miles per gallon against the amount needed to refill.

Have you had the timing checked recently? Are the spark plug gaps correct? Any holes in the exhaust system?

[TooMany2cvs]

Originally Posted by Saab 16s Stubby

How are you calculating the 15/24.

US gallons, don't forget - so that's 18/28mpig

Normally I fill the tank and reset the trip, run it to the low fuel light and then refill and calculate the miles per gallon against the amount needed to refill.

Yup, preferably over several tankfuls.

Doing it over a fiver's worth is pointless.

[Earth Brown]

that is about right I think....

Maybe change the o2 sensor out if problem persists, may be a little off after a hundred or so thousand miles.

K

[turbo1992]

I have 155K on mine and gas mileage [getting into boost often] is about 20-24 mpg. I was thinking a new o2 would help

[crwchf01]

Start checking your vacuum lines for leaks, and check all your manifold sealing points for hard/cracked/brittle rubber parts. Lived down there for 7 years and know how brutal weather can be on vacuum line and rubber parts. However, I would suggest the following tools if you are going to change the manifold seals and they are hardened- good flashlight, mechanical fingers, a set of needlenose pliers/ forceps and a bit of patience. The fingers will be for when pieces of the rubber crack off and fall back in the manifold., and the light to spot them.