Horrible gas mileage after cam install...
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Hi everyone, I recently started to daily drive my 94 Formula 6spd after rebuilding the motor and doing a cam swap at the same time (this car sat for over 2 years wrecked); before it got about 19 MPG with 50/50 highway/city driving. Now, its averaging 150 miles per tank which is about 10-11 MPG....needless to say with gas prices the way they are it is getting expensive real quick to fill up every 3 days. I know f-bodys are not meant to be gas savers but this is ridiculous....I also have a 99 Firehawk and consistently get 19-20 mpg in that car with the same driving style, so I'm not driving like a bat out of hell all the time. The cam I chose is not that big so it should not cause that big of a drop in mileage...I'm running a Lunati Voodoo 60121 (219/227 515"/.530"), 1.6 RR, beehive valvesprings, 52mm TB, CAI, mid-tube headers, no cat, magnaflow exhaust, and a PCM for less mail order tune. Also the mass airflow sensor and coolant temp sensor (on the water pump)were replaced recently. My buddy who helped me with the motor says the valves might need to be re-adjusted...could that cause this bad of mileage? Also I noticed last night when I filled up the tank I kept getting a strong gas smell in the car while driving...I got home and looked up under the car and could smell gas but it's not leaking or anything....ideas anyone? I'm taking it to a local shop next week for a dyno tune....maybe that might help but I want to make absolutely sure all mechanical/sensor issues are fixed before I get it tuned. HELP!
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if the smell of gas is that strong the tuner probably won't let you on the dyno. Check for leaks at the injectors and check your spark plugs. Your car sat for two years, could also be a weak ignition system. Just my .02¢
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Im having the exact same problem with basically the same car/setup. Im pretty sure its the tune, being that its mail order they dont want to motor leaning out and going boom so just dump fuel. Im gonna pick up a windband kit soon and have the tuner use that to tune it
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Yes, it's a stock replacement MAF from autozone; still has the screen and everything....also I have not been driving it THAT hard to get 10 MPG...just put in a new clutch and have been taking it easy the last 2 tank fulls to break it in by driving "normal" most of the time. The worst it ever got before the cam/mail order tune was about 200 miles to a tank. And did I mention it smells rich as hell? I guess most of the smell is due to no cat. Also, the spark plugs, wires, ignition coil, ignition control module,cap and rotor were replaced during the rebuild. I'm gonna have my buddy re-check the valve adjustments and hopefully the dyno tuner can fix whatever is wrong with the tune if that is the case.
Anybody from the Charlotte area familiar with Sigma Six Dyno Services in Concord? I was referred to get a dyno tune from here since there are very few LT1 dyno tuners around anymore....it's all LS tuners now. Hopefully they know what they are doing because it runs $400 for 3-4 hours on the dyno.
Anybody from the Charlotte area familiar with Sigma Six Dyno Services in Concord? I was referred to get a dyno tune from here since there are very few LT1 dyno tuners around anymore....it's all LS tuners now. Hopefully they know what they are doing because it runs $400 for 3-4 hours on the dyno.
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When I did my Lunati 60121 cam swap, my PCMforless mail-order tune was way off during part-throttle. There was bucking, floating idle issues, and decceleration pops before I had someone local tune it out nice and smooth. I can see that being an issue for MPGs. Their WOT tune never missed a beat though for anyone who's wondering.
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FWIW, I have a big H/C car and I get 13-15 city (less if I'm in it) and usually high teens low 20s on the interstate.
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FWIW, I have a big H/C car and I get 13-15 city (less if I'm in it) and usually high teens low 20s on the interstate.
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high teens around town if you BABIED it and low to mid 2x's on highway, but high 20's in town and over 30 on highway... not happening...
FWIW, I have a big H/C car and I get 13-15 city (less if I'm in it) and usually high teens low 20s on the interstate.
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Last edited by wrd1972; 04-07-2011 at 07:58 PM.
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FWIW, I have a big H/C car and I get 13-15 city (less if I'm in it) and usually high teens low 20s on the interstate.
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