Extreme Hesitation and a tick when warm...I'm going crazy - PeachParts Mercedes-Benz Forum

sumwilljoe · #1 12-31-2007, 05:54 PM

I have a 1968 280 SE. w108 m130. This car is driving me crazy right now!! This should sum it up as best as I can:

A valve adjustment was recently done. The first time it was not done correctly and loss of power and a tick occured. After one quick trip around the block, the car was parked. It was then towed to someone to have the proper adjustment done. Unfortunately that didn't solve anything. With help from our friendly mechanic we bagan trying to trouble shoot. The ballast resistor was broken so we replaced it. It was suggested that maybe we had bad gas, so we put "Heat" into the tank.
This hesitation has occured before and it turned out to be fouled spark plugs, so we tried replacing them one more time. They were fouled instantly. We had to give up temporarily and the car was towed home.

Today I turned down the idle speed air screw and let the car warm up. The tick only starts once the engine is warm. I was able to get the car above 15mph for the first time since this all began, but there was misfirings while driving and hesitation whenever I tried to drive from a stop. I pulled the plugs and cleaned them up. When I tried to test drive the car again, my oil pressure would fluctuate once I put the car in reverse. I parked it, turned it off and then turned the idle speed air screw one more quarter turn. The car's oil pressure did not fluctuate anymore and I attemped another quick drive. Still the hesitation. Then there would be a sudden surge of power that would cut out again. The car seemed to do better once it had shifted into third, but after a block and a half it wouldn't gain enough speed/power to get out of first. I managed to limp it home.
I don't know what else to try. I'm at a complete loss. Any ideas would be greatly appreiciated.

Thanks!

300SDog · #2 12-31-2007, 06:38 PM

How about ignition components specially with fouling of plugs. Wires, noise suppressor caps, points, rotor, condenser, pigtail ground all check out? Could be yer running on 3 of 6 cyls with just bad wires need cut back 1/2" or so, or couple of bad radio suppressor caps. I would not assume it's fuel or valve timing related until strong spark's proven at all 6 cyls. Blue not orange as I'm sure you know already. Heck, even distributors themselves been known to wear out. Indicated by scuffed dist cap contacts from rotor spinning unevenly.

georgel · #3 12-31-2007, 07:44 PM

Quote:

Originally Posted by 300SDog

How about ignition components specially with fouling of plugs. Wires, noise suppressor caps, points, rotor, condenser, pigtail ground all check out? Could be yer running on 3 of 6 cyls with just bad wires need cut back 1/2" or so, or couple of bad radio suppressor caps. I would not assume it's fuel or valve timing related until strong spark's proven at all 6 cyls. Blue not orange as I'm sure you know already. Heck, even distributors themselves been known to wear out. Indicated by scuffed dist cap contacts from rotor spinning unevenly.

All good suggestions. especially replace the old condenser. and distributer cap. ticking could be an out of adjustment valve. But that is down the line. Instant fouling of the plugs, likely means an Ignition problem. Test the coil. could be bad. Check wires as above. also check the ground wire inside the dist. To make sure it is in fact grounded. I have run into bad condensers a few times over the years. In some cases the car won't run at all.

MunichTaxi · #4 12-31-2007, 10:56 PM

BTW, what kind of spark plugs are you using?

ozawa · #5 01-01-2008, 03:28 AM

what do your points look like and have you checked your dwell?

try unplugging the cold start injector...perhaps it's stuck on? (you could test the feed with a test light.)

as others have mentioned, i would check all of your basics: fuel pressure and volume, all of your ignition parts and settings, (plug gap, dwell, timing, etc.) sounds like you're running too rich to me but make sure all of your baseline settings are within spec. before chasing other things.

think basics first!

meltedpanda · #6 01-01-2008, 11:37 AM

had this very thing on my 220, timing and dwell was the issue. Providing, as mentioned, you have good spark, look there. Also by fouling are they oil or gas fouled? I guess you could have a compression issue?
Start with advanced timing, listen for the "sweet spot" and go from there.
Let us know
BTW - fuel delivery is good? Filters all clean? ( I think you have an intank filter)

sumwilljoe · #7 01-27-2008, 09:28 PM

Ok...some progress! First of all, my plugs were gas fouled. Spark wasn't great. I replaced the plug wires, plugs, cap, rotor, condensor. The points were blown so I replaced them as well. The car seemed better, but would completely bog out when shifting into second. Unplugged the CSV and success!! Car runs great but that tick hasn't gone away. I'm planning on getting another oil change to deal with the gas in the oil. Maybe this will help? I'm also going to replace the CSV but in the mean time does anyone know if its a bad idea to run the car for a bit without it? Thanks for everyone's help!!

Arthur Dalton · #8 01-28-2008, 02:14 AM

If you are saying that you disconnected the CSV wire/power source, then you problem is not the CSV..it is a stuck CSV relay or Termal Time sw.

See if there is 12v at CSV with engine running.. there should not be any power..... should only be 12v to CSV when starter is cranking engine.

A leaking CSV is a mechanical fault , but power to CSV with engine running is an electrical fault.

There is a Test port on the CSV..It is the 6mm cap screw plug on the side..
You take that test plug off after you start the engine..there should not be any fuel coming out that port with engine running..if there is , the CSV is leaking by. If it is, then disconect the wire to CSV..if it still leaks , the CSV is at fault..but if the wire disconnect stops the leak , then you have an electrical problem...

See post #4

http://www.peachparts.com/shopforum/vintage-mercedes-forum/180964-how-time-my-injection-pump-post1436891.html?highlight=test+port#post1436891

Most MFI CSV problems are dirt holding the valve open..you can take it apart and clean it ..you can also re-lap the seat with fine compound.
If gas is fed to engine thru the CSV when running, it just pours extra unmetered fuel into the engine and bogs it right down..specially at low speeds b/c the air intake is low at low rpms...will foul plugs out in 5 min...