Author Topic: stumbling motor 66 230 sl bad gas?  (Read 1747 times)

merrill

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stumbling motor 66 230 sl bad gas?
« on: March 07, 2021, 16:30:53 »
i think the week long cold snap in Texas caused the gas in my 66 to go bad.

Drove the car before the cold snap and it ran fine. 
(recent partial tune up,  adjusted points, set timing, new fuel filter, oil and oil filter, new spark plugs)

During the cold snap, the car was stored in the garage and it had about 1/4 tank of gas in it the 9 days we had temps below freezing.

took the 66 230 out for a drive today,  it had bouts of stumbling between running perfectly.
Filled up the tank and the stumbling was more pronounced.

I wonder if the 9 day cold snap caused the winter blend gas in my tank to go bad?

i hope there isn't an issue with the fuel pump.



Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

Jordan

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Re: stumbling motor 66 230 sl bad gas?
« Reply #1 on: March 08, 2021, 13:06:16 »
Don't think the cold weather would have caused the gas to go bad or everyone else would be having issues.  As your tank was only 1/4 full you probably got condensation in the tank and now you have some water in your gas.  Just a guess at this point but if everything was fine before the cold snap that is the only thing I can think of that would cause your problem.
Marcus
66 230SL  Euro 4 speed

Cees Klumper

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Re: stumbling motor 66 230 sl bad gas?
« Reply #2 on: March 08, 2021, 13:24:37 »
Agree that it seems very unlikely that the gas having geen subjected to cold is the cause. I would look elsewhere, for example in the ignition system (loose wire , short circuit in the distributor maybe, that sort of thing).
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

merrill

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Re: stumbling motor 66 230 sl bad gas?
« Reply #3 on: March 10, 2021, 19:08:57 »
hi all,
thanks for the responses,

i took the car back out today, it ran fine until the coolant temp got up to normal operating temp.

then the motor started to stumble,   looks like i need to look at the wrd circuit.
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

Benz Dr.

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Re: stumbling motor 66 230 sl bad gas?
« Reply #4 on: March 10, 2021, 22:49:07 »
Sounds more like a fuel delivery problem. Not so much running lean as not enough fuel or fuel starvation.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

merrill

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Re: stumbling motor 66 230 sl bad gas?
« Reply #5 on: May 02, 2021, 19:13:14 »
hi Dan
your hunch was mostly correct,  i went out to drive the car today and she didn't to start.

after several tried she did, backed the car out and had to get out of the car to shut the garage door and saw a spot on the garage floor which smelled like gas.

looked under the car and sure enough the high pressure hose from the fuel pump to the metal line was leaking at or near the hose clamp.

pulled the car in,  shut it off,  trimmed the line etc,   

took the car for a drive and it ran fine.  even on the freeway, i opened it up to see if maybe there was a fuel starvation issue and it purred at 5000 rpm.

made a stop and sure enough when i was close to home it stumbled a few times, then when pulling into the drive at idle it died.....

got it started again and pulled it in.    going to have to keep looking for another culprit.

thanks again
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230