Help! Running very rich - need good VA tech

[raftel]

My in-laws have complained that their newly purchased 280 SL is not running well.  Running irregular, hesitating, etc.  The car has covered less than 1000 miles in the last 10 years, and in that time has had the fuel system cleaned out and the cylinder head rebuilt.

A local indie that we had used reliably for years changed out the spark plugs but the problem only got worse.

I started looking at the car by checking the car and rotor.  There was some wear and pitting, but not too bad.  The Beru plug wires checked out too, at 4800 ohms.  Dwell was 41 degrees, but I could not check timing as I was unable to get a reliable firing of my Sears timing light.  I removed the plugs and they were covered in soot - after only 500 miles of use.  I then also noted that some of the rods in the linkage were bent or misaligned.  Driving the car I noticed it was sluggish, smelled rich, and made lots of black smoke on acceleration.

It seems that my mixture is rich, but the misalignment of the linkage takes this job out of my comfort zone.  Since the indie we previously used has demonstrated his competence to us for probably the last time, I really need suggestions for a good vintage Mercedes tech in the northern/central Virginia area - help!!!

Robert

[merrill]

robert,
new linkages are cheap and they can be ordered thru your local mb dealer.  if you need the part numbers call the classic center and they can give you the part numbers, availabilty and price.

as far as running rich, remember when cold the car will run rich till it gets warmed up.  

with some test lights you can check if the cold start valve,inj pump selenoidss etc can be tested.  

do you have a haynes or mb manual?  this forum and the manuals will help out a lot.

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

[Mike Hughes]

If you are in Fredericksburg you can head north to the D.C. area or head south to the Richmond/Tidewater area.  I have used Don Pool in Falls Church.  Don was referred to me by my Pagoda-owning boss, who has known him for 25+ years. Now you just need someone from Richmond/Tidewater to give you a referral and you can choose!

- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havanna Brown (408)
  Light Beige (181)
  Cream M-B Tex (121)

[raftel]

Digging a little deeper, I finally freed off the little air filter from the "heat feeler" or control valve unit.  Even at operating temperature, there was strong vacuum there, so I suspect, as far as my Haynes manual and other sources, that it is worn out.  I tried looking at some of my usual MB parts sources online, but none list it.  Does anyone have a recommendation?  The part number I have from my literature is 000-203-9575.

I've seen Don Pool mentioned from a number of sources, and I will recommend that my in-laws take the car there.  I may just take my 6.9 there in the future.  I'd like to see if I can replace this unit myself though, as I think it could make the difference between getting the car running well enough to drive up there vice have it towed 50 miles (it is *very* rich running).

Robert

[TheEngineer]

Fist you have to free up the cold start device. Take it off & clean it. There should be no suction at the filter when the engine is warm. Second, you should verify proper adjustment of the linkage. Joe Alexander did publish excellent instructions. If things are bent, you can straighten the rods. It's soft steel. Also check for the proper heat range of the plugs. You must get to know your car to enjoy it. It's one of the nicest automobiles ever designed and a pleasure to drive.

[merrill]

robert
hans at H&R can probably repair the part.

he repaired my cold start selenoid and wrd thermostat (one on inj pump)

do a search in this forum for his number

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

[merrill]

robert
hans at H&R can probably repair the part.

he repaired my cold start selenoid and wrd thermostat (one on inj pump)

do a search in this forum for his number

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

[raftel]

I have 631-589-1600 for Hans at H&R Fuel Injection.  I didn't know that the control valve in the injection pump (the one that has coolant running through it) could be repaired, the info I had indicated that the thrust pin wore down with age and caused rich running, requiring replacement.  Note that this is not the cold start valve - that one was serviced recently, but could probably stand another look.  Thanks for the tips, I'll try to go through it patiently and methodically before we call in the cavalry (aka, Don Pool). I'll try to post some pictures of the bent rods.

Robert

[TheEngineer]

Robert: The device you are talking about is installed on top of the injection pump. It comes off by removing two screws and the water hoses. Inside is a wax element, similar to what you find in a thermostat, that moves a piston up and down. The piston exposes an opening. When it is open additional air is sucked in thru the little filter, making the engine run faster. Because your car did sit so long, the piston most likely is just stuck. You can fix it easily.
The cold start device is on the intake manifold all the way to the outboard side. A small solenoid pushes it open for a very short time. Fuel is supplied to it whenever the fuel pump runs. Trace the fuel line. When the little valve leaks more than 3 drops/ minute, you run rich all the time. Inspect it for leakage by removing the solenoid (two screws) That gives you a direct view. Verify that the solenoid pushes out when you start the cold engine. It may not work right because the car sat so long. The valve can be made to stop leaking by machining the female part of the seat. Use a countersink for woodscrews. The bit acts as a pilot. Just turn it by hand: Very little removal of material is necessary. Check for leakage by putting a little oil on the closed valve and blow air from the other side.

[113gray]

Robert, If your folks don't want to untangle this themselves, Import Autohaus in Richmond is familiar w/ these cars & has a decent reputation, in business since '69. They have three locations here. They are not perfect, but are probably better than the dealers for old cars. 804/673-9171 is the West Broad location that I have on file. Good luck.     -JP-

[raftel]

113gray-  

Thanks for the Import Autohaus recommendation- I took my 6.9 there.  Unfortunately, the guy they had who was familiar with the older cars left the shop, and the owners, who have this familiarity, don't work on the cars anymore.  This leads to a lot of misdiagnoses and run arounds.  Not that they have poor intent, they just don't have the familiarity with the older Benzes anymore.  From my location (Fredericksburg)  Don Pool is actually closer too.  I expect my in laws will have the car towed there tomorrow, as I couldn't spare the time to try again today and we need to find a good local tech anyway, so we'll try them out.

Robert