Author Topic: Skipping and bucking at 60mph  (Read 6715 times)

menesesjesse

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Skipping and bucking at 60mph
« on: September 29, 2008, 10:10:07 »
Hi all.  I just got my 66 230SL on the road this weekend.  After a long run to getting her to run right I finally thought i had it.  I went through the linkage tour a had my distributor rebuilt and the car was running well.  I drove it for some short distances until saturday.  I took her out and it pulled well and shifted good.  I do have a a/t modulator that is leaking but I am not sure that is my problem. When I get her to 60 mph at about 3000rpm she is good and steady but when I push her to 3500-4000rpm she sputters and bucks a bit.  The conditions almost feel as if there is a governor preventing me from pushing the motor past 3500rpm under load.  The car idles well at 750 and doesnt shake.  The dwell was adjusted and is good.  My fuel pressure at idle is 18-25psi  Has anyone experienced this issue while driving?  Thanks for any help
Jesse
1966 Mercedes 230 SL auto
2003 Mercedes E500
1992 Ford F150
1994 Ford Bronco
2019 Shelby GT350R
1967 Mercury Cougar XR7

hauser

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Re: Skipping and bucking at 60mph
« Reply #1 on: September 29, 2008, 11:14:41 »
I had this happen to my car a few years ago.  I took it to the shop and they installed a Crane system and it hasn't lost a beat since.

graphic66

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Re: Skipping and bucking at 60mph
« Reply #2 on: September 29, 2008, 16:50:19 »
How did these cars run at 60+ before the electronic ignition was fitted. My 66' seems to run fine with the points, must be a fluke. What ever did a person do to fix a problem like this before the crane system? It is hard to believe that these cars could have ever been reliable running on points. Another fluke for my car, running perfect for the last 4000 miles on the same set of points. I really think that the archaic breakerless ignition running with a distributor really is a very outdated upgrade. I want a crank position sensor and six coils, why bother with old technology that never worked right, meaning of course those pesky points that requires some mechanical skill to install. I'm not even going to suggest that your car could possibly need that very outdated mechanical injection pump replaced with the new electronic injection to run correctly. And while your under the hood get rid of that outdated cable spinning the tach, whoever thought that would ever work. And that goofey capillary temp gauge. We could just run everything electronic and this would be just like a new car.

Mike Hughes

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Re: Skipping and bucking at 60mph
« Reply #3 on: September 29, 2008, 18:09:54 »
In other words, you think he should check his timing and also check for proper function of the distributor advance/retard?  ;^0
- Mike Hughes  -ô¿ô-
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glennard

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Re: Skipping and bucking at 60mph
« Reply #4 on: September 29, 2008, 18:30:10 »
Ah yes, near PPP-Perfect Pagoda Persiflage




quote:
Originally posted by graphic66

How did these cars run at 60+ before the electronic ignition was fitted. My 66' seems to run fine with the points, must be a fluke. What ever did a person do to fix a problem like this before the crane system? It is hard to believe that these cars could have ever been reliable running on points. Another fluke for my car, running perfect for the last 4000 miles on the same set of points. I really think that the archaic breakerless ignition running with a distributor really is a very outdated upgrade. I want a crank position sensor and six coils, why bother with old technology that never worked right, meaning of course those pesky points that requires some mechanical skill to install. I'm not even going to suggest that your car could possibly need that very outdated mechanical injection pump replaced with the new electronic injection to run correctly. And while your under the hood get rid of that outdated cable spinning the tach, whoever thought that would ever work. And that goofey capillary temp gauge. We could just run everything electronic and this would be just like a new car.


hands_aus

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Re: Skipping and bucking at 60mph
« Reply #5 on: October 02, 2008, 04:49:39 »
What about checking for full opening of the throttle at full pedal
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL #114, auto, ps , 717,717
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menesesjesse

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Re: Skipping and bucking at 60mph
« Reply #6 on: October 02, 2008, 13:05:36 »
Update
I advanced the timing and it seemed to better the situation till the car came up to warmer running temps.  The throttle does open all the way because I checked this during the linkage tour.  I pulled the plugs yesterday and they looked brown. I decided to change them with a new NGK set and gapped them to .025 to see what would happen.  The car started up and ran well.  I took her on some back roads and got her up to 4500rpm at 75mph and she seemed good.  I will monitor her since I havent been able to drive her for more then 40 minutes without fear of rain(no top). I think will take a longer ride this weekend to see what happens.  I keep everyone posted.
Jesse
1966 Mercedes 230 SL auto
2003 Mercedes E500
1992 Ford F150
1994 Ford Bronco
2019 Shelby GT350R
1967 Mercury Cougar XR7

Benz Dr.

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Re: Skipping and bucking at 60mph
« Reply #7 on: October 04, 2008, 13:08:11 »
I don't want a new car, I want an old car. That's why everything in my car is....old. I want to feel it shake, rattle, run rough until it warms up, nose dive on hard braking and every other quirky thing that 113's are noted for. It's why I like my car - not because it's perfect but because it will always be wrong.
I like the look, sound and smell of an old car. Take that away and you have just another old car or just another car. It's why my newest car is still 20 years old and why I probably will never buy a another new car. I can fix this stuff myself and when it dies I'll part it out and make other ones live. The purest from of driving expirience is being at one with your auto enjoying all the sensory inputs.
Have you given yours a good Italian tune up lately?

Oh, one more thing. I think .025'' plug gap it a bit too close and may result in misfire later on when the plugs get worn a bit. I use .032'' which is generally standard setting for most plugs.

[Moderator addition, "Italian Tuneup": running a car at speed allowing the higher rpm to clean up carbon, gunk, etc. that a high compression engine might accumulate when driven at slow or moderate speeds.]
« Last Edit: October 04, 2008, 15:12:31 by 280SL71 »
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

menesesjesse

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Re: Skipping and bucking at 60mph
« Reply #8 on: October 06, 2008, 13:00:07 »
Update 2
I will try 032 later today.  The car was running good for a little while but then returned to its old self and sputtered at 4000rpm.  The car would then lose all power at WOT and then stall out 1mile later.  I might of pushed her too hard this weekend because she is really smoking bad now.  It is so hard to find the right settings but I guess thats why we have night so we can sleep on it and comeback with new ideas.  I will keep you posted.  Thanks
Jesse
1966 Mercedes 230 SL auto
2003 Mercedes E500
1992 Ford F150
1994 Ford Bronco
2019 Shelby GT350R
1967 Mercury Cougar XR7

Benz Dr.

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Re: Skipping and bucking at 60mph
« Reply #9 on: October 06, 2008, 17:00:46 »
This sounds a lot more like a fuel delivery issue to me. Runs out of gas after a short drive.
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