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- From: clarke@ll.mit.edu (Ken Clarke)
- Subject: Re: Help... Car MPG has become very poor....
- Message-ID: <1992Dec31.163330.2236@ll.mit.edu>
- Sender: news@ll.mit.edu
- Organization: MIT Lincoln Laboratory
- References: <1992Dec30.155722.15084@wam.umd.edu>
- Distribution: usa
- Date: Thu, 31 Dec 92 16:33:30 GMT
- Lines: 44
-
- In article <1992Dec30.155722.15084@wam.umd.edu> choudhry@wam.umd.edu (Zafar Ullah Choudhry) writes:
- >I have 1985 Mitsubishi Mirage whose MPG has reduced from 30 to only 15MPG.
- >Few weeks ago it failed the emissions test and I posted the problem in
- >this news group. I suggested to change the carb. and I did that. However,
- >MPG problem is still there as is, although emissions have reduced.
- >
- >Is it possible that this problem is due to high valve clearences, because
- >I haven't adjusted them for a long time. My car has 1,20,000 miles on it.
- >Engine doesn't give any smoke while running. In the morning there is some
- >some for few minutes.
- >
- >I have also checked all the hoses for any leaks, and found non. BTW, spark
- >plugs become full with carbon within two weeks. I'll appreciate if anyone
- >can help me out of this problem.
- >
- >Thanks.
- >Zafar.
- >
- >
- > (
-
- Your comment on plugs having lots of carbon (soot) within two weeks
- leads me to think that you are probably still running way too rich on
- your fuel mixture which also cuts your mpg in half.
-
- One thought is that your replacement carburetor is still not good.
- Rebuilding carburetors is still somewhat of a crap shoot. You might
- want to try another carburetor - hope you had a good warranty on the
- replacement carb. It's kind of hard to test rebuilt carbs. With
- electrical rebuilds you can put them on a jig and see if they work or
- not. With carbs, you rebuild them and can do visual checks for cracks
- and maybe some air leak/flow tests, but how to know it really works?
- Have to put it in a car and see. Some do and some don't.
-
- It sounds like a fuel mixture too rich problem. Which leads me to
- suspecting the carb, still. Does your car have an oxygen sensor? I've
- heard of some carburetors with electronic feedback. If so, I'd
- suspect & check that, too.
-
- Good luck with it, Zafar.
-
- _________________
- Ken Clarke
- clarke@ll.mit.edu
-