Chasing my tail!

[isofast]

Hello group, looking for my error, and I am stumped. Regarding my 1969 280 four speed car 051 dist.
Car stumbled from start (embarrising) and had some hardly noticeable missing at all rpm except idle. Also when cold or hot car would sometimes require a restart or two to leave. So I first looked at linkage and noticed that long rod to throttle body was bent slightly at the ball socket end close to throttle body (looks as though on purpose) so I straightend it. Knowing these cars I should have checked with a test drive but did not and set out to fix more things that were not broken.
I changed the spark plugs with new ones even though plugs were sort of new and had a clean good looking tan/brown look. Best I have seen yet from my car. I set gap at specs ( I set gaps a little big as a rule but did not this time). Then I test drove car. Car ran better but still same symptoms. Then I changed points set them at 12 and car ran never better, and the stumble went away from launch. Also I start the car once when I leave. My problem is that not always but sometimes when I coast up to a stop sign the car will die. Sitting in the driveway I can rev the car up to four or five k on tach and the car will drop down to a silky idle other times (one in three or so) car will drop down to an idle that is so low that car dies.Joe or someone have an idea?
The car runs so good that I am taking it for a nice drive in the hope that this problem will go away. I just have to rev it a little at stop signs
HELP ME


First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
First Place AACA Show winner for 2004 280SL
1969 280 4spd Papyrus White

[Cees Klumper]

Hi there Ernie - maybe something with that dash-pod-widget that is supposed to soften the return to idle? Are all your linkages clean and tight?

Mine is an automatic and so I do not have that dash-pot device.

Hey, how about a possible leak in the brake booster; apparently when there is a leak there (and/or in the vacuum line that goes to it) it affects the idle when you brake, as in coming to a stop.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[isofast]

Thanks and hello Cees, I will check those items. Also I have been reading about fuel shut off solenoids but I thought they kept sputter to a minumum only?  (third and fourth Manual trans) And had nothing to do with idle? Can the butterfly in the throttle body get sticky and snap shut enough to kill the motor?
Is the ground wire (bare cooper strand) inside distributor that is soldered to body of distributor and attached to one side of points for radio suppresion or something more important? Mine is kind of beat up.
Thanks a bunch.
Ernie

First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
First Place AACA Show winner for 2004 280SL
1969 280 4spd Papyrus White

[isofast]

The Italian tune up with some other minor lube on linkage and dashpot adjustment seemed to work! Thanks Cees. Now if I can figure out the three grand miss...I am going to clean up and lube distributor in the morning, I only put some lube on rub block. I
forgot when I was chasing my tail. Has anyone rebuilt their 051 cast iron distributor lately? How much is a rebuild kit? I used to use a variation of springs on small block Chevys that would allow a light/medium and a medium tension spring to help launch heavy 57 Chevy cars. It would improve the torque curve. Has anyone tried hopping up an 051?  My Pagoda has what feels like a slight lean miss at three thousand rpm. I will recheck burn on plugs and do the Joe A
Co test also. It seems worse when cold. But it might just need one more Italian tune up.[:p]

First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
First Place AACA Show winner for 2004 280SL
1969 280 4spd Papyrus White

[Cees Klumper]

The butterfly in the throttle body should be almost shut anyway, so if it would close all the way that should not make a difference. But if on your car it's adjusted to be partly open, and that is what is supplying the air for the idle mixture, then I suppose closing it all the way would cause the engine to stall due to a lack of air.
Dan Caron (BenzBarn / Dr. Benz) sells rebuild kits for the 051 distributor, he also rebuilds them and I think in general knows all about them. The engine should not miss ever, if it does there is some sort of problem.
Good luck on solving the remaining issue.

The one thing I really like about these cars is that, once you fix things, they tend to STAY fixed for years and years. A welcome change from the haphazard performance of my "Prince of darkness Lucas-equipped" Triumphs of days gone.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello Ernie,

Don't forget to check the ignition points and dwell! Check the ignition wires and ends with an ohm meter in case one has gone bad. The distributor should also be checked to see if a centrifical flyweight springs have not broke (see if the rotor spings back).

Joe Alexander
Blacklick, Ohio

[isofast]

Hello Joe,  wires are new ohm meter on all read about 1k.
I am going to put my mighty vac on the vacuum line to see if weights throw out and back. Also to check diaphragm for its ability to hold hg or vacuum. I read some very interesting things on the Ponton website regarding tune up tips! If anybody wants to look at it I will add a link, much of it pertains to our cars as well. I think it is well done. What do you folks think?

Ernie

Finback-Ponton websitehttp://http://www.mbzponton.org/valueadded/maintenance/pointgap.htm

First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
First Place AACA Show winner for 2004 280SL
1969 280 4spd Papyrus White

[ja17]

Hello Ernie,
Yes the ponton site is a good resource. A lot of documentation has been done by Jeff Miller and the group. Many good technical articles and photos document the main site and the "Ponton Plus" annex. My Alias on this site is "Joehio".

There are about 350 members but they generate lots of posts, sometimes not ponton or Mercedes related.

Another point of interest is they have had very nice porceline grill badges produced, and T-shirts for their group.  

They too originated from a "Yahoo Group" and expanded into a full web site. There are  a few of the W113 guys on this site also.

Unfortunately the ponton sedans do not share much in common with a W113, but there are items like the ignition, rear brakes, basic suspension, radios, and other odds and ends which may share some things in common with at least the early W113s.

Joe Alexander
Blacklick, Ohio

[isofast]

As it turns out my Pagoda is tuned to perfection.
I finally figured out why the car would die sometimes.
To say I feel stupid is an understatement.
I noticed that if I have foot on the clutch the car would idle but if I put the trans in neutral and then let out the clutch when at a stop sign for instance, the car dies. If I pump the clutch pedal two or three times it will not.
It is as if the motor is getting pulled down and dies.
I opened my clutch resovior and it was low not much but low.
So I suspect that air in the system. I looked under the car briefly and the slave cylinder is a little wet. Any one done this lately? Any thing to look out for when replacing? I know that you have to bleed properly and also replace any hoses that might be constricted like when a brake hose swells on the inside.
I think this might be the only procedure that Bob Possell has yet completed (only because his beutiful Pagoda is automatic).
What do you say Bob come up to Chicago and wrench on my car a little?

Best Regards
Ernie

[jeffc280sl]

Ernie,  

The slave is easy to replace.  If it's leaking the clutch plate may engage even if the pedal is depressed. This would place drag on the engine and may account for low idle and shut down. If the car was in gear it would feel like the car wanted to move even though the clutch pedal was depressed.  

This does not explain your behavior in neutral where the car idles fine until you release the clutch pedal.  I think a better cause for you problem my be a failure in the circuit which controls the fuel shut off solenoid on the IP.  On the manual trans model the shut off solenoid is activated by a switch mounted on the clutch pedal as part of the emissions system.  Have a look at the Haynes manual at figure 3.78. The solenoid is only supposed to activate if you are in 3rd or 4th gear and coasting with the clutch pedal released.It could be that one or both of the switches located on top of the trans are for 3rd and 4th gear are not working properly.  Try disconnecting the wire on the rear of the solenoid on the IP and see if the problem continues.

Jeff C.
1970 280SL 4-speed

[isofast]

Thanks for getting to me so fast! Wow!
I will try to disco the shut off solenoid.
If indeed the switches on top of trans are bad what kind of a pain is it to replace them?
Thanks a million
Top down weather in Chicago today and it is my birthday.
Ernie

[jeffc280sl]

I wouldn't worry about the switched unless I was a enviro nut.  When coasting in 3rd and 4th gear with the clutch out fuel is shut off via the solenoid to reduce unspent fuel going out the tail pipe.  At this point your foot is off the gas pedal and I don't know what improvement if any is made in the emissions.

Good luck,  I hope this is your problem because its easy and conclusive.

Jeff C.
1970 280SL 4-speed

[isofast]

Jeff thanks for all your help. Why do you think that if I depress clutch pedal three times at the stop light the clutch works as it should and car idles perfect. But if I just through the stick in neutral and dump the clutch it kills the engine. I am familiar with solenoid but do not think this is the problem. Although I will unhook the solenoid and let you know. I am going to start a new thread regarding clutch slave. Thanks and I will get back to you with results of fuel decel shut off unhook.
Best
Ernie

[George Davis]

Ernie,

I agree with Jeff, it doesn't seem likely that the clutch slave is related to engine dying at idle.  It should idle in neutral with clutch engaged just fine, there is almost no load on the engine in that situation.  My car (manual trans) had similar symptoms for a while; idled fine some times, idled rough and died other times.  I retuned it about 3 times, and raised the idle speed a bit.  This helped but didn't quite cure it.  I then adjusted the vacuum unit in the distibutor to retard timing about 1 degree at idle, then retuned at idle (about 850 rpm), and it no longer dies.  I can't really explain why this worked, but it worked.  No parts replacement at all, just making those adjustments.  In your case, I'd suggest a careful retuning at idle and maybe raising the idle speed a bit first, that may be all it takes.

Good luck!

George Davis
'69 280 SL Euro manual

[jeffc280sl]

Can't say for sure without looking at the car.  There is a small switch that opens, I think, (can't remember for sure now) when the clutch pedal is pushed in.  Its closed (I think) when the clutch is engaged and no pressure is on the pedal.  There are also small switches on the top of the trans and small arms that make contact with them when in 3rd and forth gear.  The arms could be bent, switches broken, who knows.  However in your car when in neutral the switch may be enabled.  When the trans switch and clutch switch are closed, I'm pretty sure, the circuit causes a relay to activate the shut off valve.  The switches are old and dirty so contact may be unreliable.  What happens if you push the clutch in 4 times or six times?  Who knows.  I do know there is a switch activated by the clutch on manual trans 280SL that under certain conditions is designed to cause the fuel solenoid to shut off fuel to the FIP.
The symptoms seem to match an electrical problem with clutch.  That's the only electrical circuit related to the clutch that I know of.  Shutting fuel flow off would cause the engine to stop. Ergo try it, nothing but one wire to remove so its easy.

Jeff C.
1970 280SL 4-speed

[bpossel]

Hey Ernie!

You're right I have'nt done that one yet?  I wish my 113 was a manual so I could do that one....

  Happy Birthday!
Hope you have a great day and weekend.
Regards,
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Naj ✝︎]

isofast
 

quote: My Pagoda has what feels like a slight lean miss at three thousand rpm. I will recheck burn on plugs and do the Joe A
Co test also. It seems worse when cold. But it might just need one more Italian tune up.

Do you now know what the cure for this ailment is?

Sure could use some ideas.

naj


65 230SL
68 280SL

[isofast]

Naj cured miss at three grand by checking dwell in my case dwell was off. Also lubed distributor weights. So not sure which helped more but dwell was off a bit. Looking forward to meeting you at RT 66.
How do you like your 107?

George car idel is just fine with clutch engaged. But I much like you, think Jeff may be correct.

Jeff I am still getting back to you regarding unhooking bottom solenoid. I am not a tree hugger but I belive every function on the car is important, so, I am looking at the switches I think one is on the firewall but have to look at BBB. I would have unhooked solenoid yesterday but a B-Day party and Miller Light ambushed me.

Bob P. you have a lot of time on your hands I can not find the time to unhook one simple solenoid wire. I wish I had your ambition.

BEST REGARDS
ERNIE

First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
First Place AACA Show winner for 2004 280SL
1969 280 4spd Papyrus White

[Naj ✝︎]

Hi, Ernie,
 

quote:
Naj cured miss at three grand by checking dwell in my case dwell was off. Also lubed distributor weights. So not sure which helped more but dwell was off a bit. Looking forward to meeting you at RT 66.
How do you like your 107?

Thanks for your comments.
I rebuilt distributor and now running with crane so still looking for clues.

Re:107
We were very lucky to find a good one within the week I was there.
1st owner had it from new ('88) to Dec 2003 and 2nd owner for just over 2 years. 75k miles and very clean condition. Nothing needs doing except an oil change as there is a drip from the oil pan drain plug seal. Hopefully will get us to CA and back without drama.  
Looking forward to meeting some of our members here along the way.

naj


65 230SL
68 280SL

[isofast]

Thank you Jeff the unhook solenoid worked!!!

First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
First Place AACA Show winner for 2004 280SL
1969 280 4spd Papyrus White

[jeffc280sl]

Your welcome Ernie!  Glad to hear the problem was a simple one.  If you really want to hook up the switches and need some help let me know and I'll see what I can do.



Jeff C.
1970 280SL 4-speed

[Benz Dr.]

If the engine dies when you push the cluch pedal in it's very likely that the throw out bearing is nearly siezed up. I had one that went on a long drive from home and I had to start the car in gear and it would almost stall the engine even at speed while shifting. This happened without warning and very quickly.
I always replace this bearing when ever I remove a transmission unless I know the bearing is new.

Changing idle speed is often caused by sticking flyweihts inside of the distributor. The electronic units commonly available today do nothing to cure this problem and the distributor will need to be taken apart and cleaned. New springs usually cure this but I've seen where the cam was actually siezed on the main shaft running through the distributor body. There's a small felt wick underneath the rotor that needs a few drops of oil every time you do an oil change and this is often overlooked.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[isofast]

Thanks Doc and Jeff and group.
Doc car would idel fine with clutch in. It also would idel fine with clutch out... some times.
The problem was when I would get to the first or second stop light from my home. After downshifting I would throw the stick in neutral and let clutch out and depress brake pedal, you know just what you would do at any stop light that is red, then it would die just as soon as I dumped the clutch... bang it would die like you turned off the key.  Unhooking the bottom solenoid on Injection pump like Jeff C. did the trick. Thanks Jeff.
Funny you should mention throw out bearing Doc mine is starting to make occasional noise. I had better stop showing off how well my car launches from red lights. :mrgreen:
Ernie

[Benz Dr.]

A throw out bearing that starts to make noise will fail very quickly once all the lubricant has dried up. The hotter it gets the more the grease gets burned up.
These cars have hydraulic clutch and there's always a small amount of pressure on the throw out bearing. I think it spins all the time but not under load - that only happens while the clutch pedal is pushed in. A bearing can last 20 years or more just like a centre hanger bearing or any other bearing on the car.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061