I have a 1985 camaro z28, with the LG4 (305 carb) NON COMPUTER CONTROLLED.

When i first bought the car a year ago i was getting 18-20mpg in the city. But it was slower, i havent done any modifications to the car just did the timing and new air filter.

Over the summer i plugged all the vacuum crap (EFE, EGR, acl motor, dist. retarder) And it ran good, didnt really care about fuel economy. prolly got about 10.

But now all that stuff is hooked up, timing is perfect, car runs so smooth. sounds so good. compression is at 175psi across all 8. And i feathered the gas around today. and got 11mpg.

Im starting university and its about an hour away, so im looking at liek $150-200 gas bills. and i cannot afford that.

Any suggestions as to why my fuel economy would be so crappy? Tommoroow im going to try an oil change, and check for vacuum leaks.

Oh, and my last tune up was 30,000k ago (did the air filter abotu 1xxxkm ago) and i clean my sparkplugs every 5,000 to get the carbon off, and they look good.

So please any suggestions.

 

dist vacuum advance is working correctly?
Hold timing gun to balancer, pinch off line and check.. or hook up to manifold vac temporarily to check.

This is non-cc so there is no O2 sensor. Too bad, that's an easy guess

Car runs smooth? All plugs look identical? Not like one is misfiring?

 

the distributor timing advance IS working properly. have tested with unplugging the line, and car just bogged. and I set timing with dist. advance off. the timing is set at 8 degrees and is running SO SMOOTH, so nice, and wont ping at all, trust me ive tried.

the spark plugs all look identical.

right now, i just hooked up the motor in the the air cleaner that brings in hot air from the exhaust manifold. Maybe thats the problem, going to head out and do some errands so i just filled up the tank. going to do another test, ill report back in 1-2 hours. with results.

Thanks for the help, any other advice? im really at wits end here.

 

I did a 10km test today, and i got 8.55mpg.

but perhaps it wasnt really long enough of a distance to be sure. Im just gonna wait till the end of the week and see what i get with the normal school and work run.

Im also going to check that my choke is opening and closing properly.