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-   -   HELP! I don't know WHAT is wrong with this car!! (http://www.peachparts.com/shopforum/vintage-mercedes-forum/22134-help-i-dont-know-what-wrong-car.html)

bachlauter 08-15-2001 05:44 PM

HELP! I don't know WHAT is wrong with this car!!
 
HI guys!!

*Sigh* I TRIED to take my car for it's first BIG drive down the street today!(It's legal now! )
:D
BUT....Ok....I let it warm up....it was idling normally...I backed it out of the driveway....brakes are working...then I start down the street. The car was running ok, but it felt like MAYBE the brakes were dragging....so, I mentioned it to my 12 year old niece who TRIED to jump out of the moving car (scared). I assured her we weren't going to DIE, but decided to play it safe and pulled into a nice flat driveway to turn around. It STALLED. I FREAKED. Here I was in some strangers driveway....broke down and my niece at this point, was RUNNING from the scene. I TRIED to restart and it did, but I put it in reverse, moved about 3 feet back and it DIED again. NOW my A**end is in the street and the whole world is coming down the street. I FLAG everybody to pass me and TRY this all again. Got about 3 more feet and...you guessed it. Blah. So I let it coast back into the street and tried to start it again and by using two feet (it's an AUTOMATIC) got the car to accelerate back up the street. (My niece was running along side me faster than I could drive it!) I ended up cutting off some dude so I could BLOW back up MY driveway.....and of course as soon as the car was home it DIED again.

So...this car seems to be stalling when I'm turning...is that some sort of power steering issue??? I don't know! :confused:
I WAS ready to have it INSPECTED....I can't even drive it down the street yet!! Geez!
:rolleyes:

~Christy

bachlauter 08-15-2001 07:07 PM

Hhhmmm...
 
Guys...

I went back out and started it to see if I could drive it up the hill and into the garage.

The car started right up and happily cruised right along into the garage, like a NORMAL car.

If the car stalls when I slow down to turn or, say, stop at a stop sign, does that mean my idle speed is too low??? When I drop it into gear it DOES idle really low and sometimes stalls...

I want to drive this car ALREADY!!!!!!!!!!!!!!!!!

:p

~Christy

cth350 08-15-2001 07:18 PM

Christy,

I expected that. Your carbs aren't balanced well enough to keep it going under load.

Your at that point where there are a dozen little details that have to be "just right".

First off, let me explain why on the turns. You're exactly right about the power steering. Simply put, the power for the power steering is putting just enough load on the engine to make it faint from the less than perfect carb setup.

Power loads on your car (in order of occurance):

1. Getting it started. Here, the starter sure helps, but only to 200rpm. The engine has to make it up to 800 rpm (which it does very well usually). The alternator adds to the load by sucking up juice to charge the battery.

2. Putting the transmission in gear, with your foot on the brake. Now, there is a big load suddenly added to the engine and the RPMs drop. You may not be going anywhere, but inside the transmission, there's lots of stuff moving and working suddenly that wasn't there before.

3. Putting your foot on the gas. You'd think that this was a "good" thing. Well, it is and it isn't. Your carbs have several stages that have to work nicely together. There's idle, the primary and the secondary. When the carbs are set up correctly, and all the adjustments are done at idle, the transition to 1200 rpm is smooth, as are the 1800 & 3000 & 4500 rpm ranges.

4. Turning the wheel. If just going straight and level was work on the engine 'cause the transmission was eating power to turn the wheels, now comes the power that little power steering pump eats to make those left and right turns more easily. That's just a sudden load change. If the last step was taxing the motor, this might be just enough to stop it. After all, on a residential street, you're not driving very fast when you turn.

5. Hills. Gee, you live in a very flat neighborhood, right? (yeah, right) You know those two spots where your poor honda lugs up the hill. Well, your benz is going to really hate that hill and you might stall going up.

You might try using a lower gear than usual for your around the block sprint next time. That will coax the engine to work in a higher RPM range. Be sure to watch the little marks on the speedometer though. There are 4 spots with red ticks. Those are speed limits per gear. If you bring the gear selector all the way to its lowest gear (2), don't go beyond the double tick mark. In the (3) gear, keep it below the triple tick mark. Under normal drive, you're at (4) and that's good 'til 109 mph or so.

The other thing to do is just a quicky test with the car still in park in the drive way. What happens if you just hit the gas and let go real fast. With the car warm, will it stall?

As for what to do next, spend some quite time (minus the kids) reading the adjustment sections again. From my memory of what was where on your carbs, the following adjustments need to be made (do them in the order of the book):

- Vent valve stop (a little bit hard to do on the rear :( ).
- Rear do-hicky that rattles.
- balance of linkages and idle screw.

Good luck and keep us posted.

-CTH

PS. Silly me, I just remembered, check your power steering fluid level. If it's low, add ATF.

cth350 08-15-2001 07:21 PM

Yup, once in gear, it's idling too low probably. I shoulda said that.

-CTH

bachlauter 08-15-2001 08:35 PM

it sounds so complicated!
 
Ok...

The RPM's are 800 in P and N...and 600 in R and 4...

AND...about the adjustments...would it just make the most sense to pay someone to do the fine tuning?? I just have my doubts about getting those right. AND....will my carbs ever work right with that jacked up vent valve thingy on the rear carb? How about that TAPE JOB on the front one?? :(

Btw....thanks for the thorough reply!! :D

~Christy

Oh...I don't think it will stall if I gas it and let up real fast..

ctaylor738 08-16-2001 07:49 AM

If it is starting and running, why not adjust the idle stop on the dashpot on the rear carb out a bit to keep it from dieing at low RPMs? Isn't that what it's there for?

Chuck

bachlauter 08-16-2001 09:14 AM

CHUCK!!!!
 
C'mon....YOU tell ME what to do!

OR...should I just try to find someone to adjust these carbs....this adjustment job SUX.....

~Christy

bachlauter 08-16-2001 02:28 PM

carb balancing 101
 
Guys!

Hi! I made myself a carb balancer out of a plastic bowl. It's not PERFECT but it works.

So....I start the car up. Btw...it was a little harder to start today. I had to give the car gas and the car acted like it wanted to stall....but anyways...I got the car started and warmed it up. I put my BOWL over the front carb and placed the measuring unit over the hole and the little ball inside went up about a 1/2 inch....

When I put the bowl over the rear carb, the rpms DRASTICALLY dropped and when I put the measuring device (what is that thing called btw??) on the HOLE the car DIED. I tried 3 more times and the car DIES everytime....INTERESTING factoid..the rear carb SMOKES after it dies...is that vapor lock??? (Or did it just crash and burn??) It's not like black smoke, it was more like thick steam...

So I moved those throttle screws (the vertical ones?). The rear one is like frozen...so I moved the front one and it made the rpms raise BUTT made the engine compartment VIBRATE HORRIFICALLY...so I put it back.

Does anyone have any comment on this?? :confused:

HELP!!!

~Christy

cth350 08-16-2001 03:47 PM

remedial carb balancing
 
Firstly, the name...

The tool is usually called a Unisyn, just like a tissue is called a kleanex (unisyn is a brand name of the more general carb synchronizer product).

Second, interpreting what you observed...

With the unisyn on the front carb (with the adapter), ALL of the air flowing into the carb is forced through the throat of the unisyn. As the air flows past the neck, it changes the pressure in that little tube. Like the tool I have, it doesn't matter exactly where the red ball goes, as long as it goes to the same place on both carbs.

It DOES help to have the ball in about the middle of the tube, but its not a big deal. You can change how high (or low) it travels by rotating the little gizmo in the middle of the unisyn. The wider the spacing, the lower the ball should rise (you're making the instrument less sensitive that way).

I bet that when you check the rear carb, the red ball shoots to the top and then dies. You can open the gizmo a bit and try again. You might have to open it a lot to get it to not stall.

It won't help to adjust it so much that the front carb doesn't register.

As for that wisp of smoke from the rear carb, that's a little bit of gas getting to something hot and evaporating. If there was a bit more air, or the fuel got a little hotter, it might well have resulted in a backfire instead. Scary, but not that dangerous. Don't have your nose over the carb when it does that.

[OK Charlie, that's all nice, but WHAT DO I DO?]

Funny you should ask that question. Answer this one first, which carb is sucking in more air than the other?

-CTH

cth350 08-16-2001 03:59 PM

The rear carb is gulping LOTS of air. How do I know that? Because the unisyn is choking off the air supply and the front carb isn't getting enough air to make up for it.

So this is what to do next...

1. with the unisyn in place on the front carb, adjust the gizmo so that it only barely registers. (So the red ball only floats up a 1/4").

2. Adjust the front carb so that the RPMs rise and the ball gets back into the middle, maybe a bit above the middle of the scale.

3. IF (and only if) it shakes like mad, adjust the idle screw at the base of the front carb OUT (counter clock wise) a half turn. If this has no effect at all, put it back where it was.

4. With the unisyn and adapter removed, hit the gas once or twice and make sure it doesn't stall. If it does, undo the change you made at step 2.

5. If you survived step 4, without stalling. test the rear carb.

6. Report on your progress and where it idles now, both in park and in gear.


-CTH

bachlauter 08-16-2001 04:26 PM

Idle screw at the base of the front carb...is that the MIXTURE screw??

You are right..the rear carb is SUCKING HARD!!! It's SUCKING LOUD!!!!!!!
I removed the vertical "screw on a stick" thing and got it lubed up at bit so I can now adjust it. I thought making it as short as possible would be the best bet....I was wrong. I have it set now somewhere in the middle and have the car idling back around 1000rpms...

That rear one is still choking out...so I'll try to do what you've suggested and report back ASAP!!!!

:D THANKS!!!!

~Christy

bachlauter 08-16-2001 05:28 PM

OK..

I've adjusted these carbs to the point where the screws have come apart!!! I finally got them back together and back on. I have the car idling normally. BUT...here's the big delimma... ANY adjustment to the rear carb DOES NOTHING!!!! I can only change the idle by adjusting the front carb.

AND what the hell is with this unisyn??? I can't freakin adjust it either??!! I took it completely apart and put it back together and the ball is still through the roof on the front carb. If I put it on that rear carb the car DIES!!! Do I want the air gap on the unisyn itself to be big or small??? I don't get it.

Does anyone have any guess as to what could be wrong with that rear carb??? I am now thinking that there is something seriously wrong with it. It's sucking air like mad....and I can't adjust it??!! Should I take that thing apart again?? And look for what?? Should I buy a rebuildable core somewhere??

I'm so pissed!!! My blood pressure is like 350/800 right now!!!!! UGH!!!!!!!!!!!!
:mad:

~Christy

bachlauter 08-16-2001 07:51 PM

I'm calm..
 
Ok...I sought out a how-to lesson on the unisyn.....I am now ONE with the UNISYN....

That doesn't mean I've made any progress....yet.

I'll keep ya posted..

~Christy

cth350 08-16-2001 09:41 PM

You've been united with the uni-syn?

To bring that red ball down, you have to open the gap on the unisyn.

There's nothing wrong with the rear carb sucking lots of air, except when the front carb doesn't.

Those first steps I gave you were just that. The idea was to get the front carb to open WIDE and take in all that it can.

Once the front carb becomes greedy, we can make the rear carb a less hungry for air. But that comes next.


So lets get the BUTTERFLY on that front carb to do what we want and open wide.

-CTH

ctaylor738 08-16-2001 10:44 PM

Why am I always the straight man? I mean first it was G-rated messages, then private emails, then phone calls, and finally a layover discreetly arranged by an admin ... Now it's butterflies and various forms of heavens knows what ...

Anyway, here's what I would try.

Unhook the linkage rod between the carbs. If the rear carb is getting more air, cut it by turning the adjuster clockwise by 1/8 of a turn. Go the same amount ccw on the front. A couple of iterations of this should get you enough in balance that you can put the unisync on and do a more exact balance.

Then adjust the linkage rod so that when it goes on it does not change the balance. Then adust the idle speed.

Chuck


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