Fuel adjustment - '74 240D - Page 3 - PeachParts Mercedes-Benz Forum

nhdoc · #31 05-30-2008, 07:08 AM

I'd suspect you may have a a fuel issue if you need to crank more than a couple of revs to start it if you are certain the GPs are all working right. Usually with the old 616's if they are "warm" (to me that means showing anything off the bottom peg of the temp gauge when you turn on the key) you shouldn't really need to glow them hardly at all and certainly not after an hour unless it is really cold out.

BathCity · #32 06-01-2008, 01:28 PM

I have removed all but 1 shim washer from the IP vacuum governor. The engine doesn't smoke as much but she is still smoking much more than she should. I took her out on the freeway again to see if running the engine at speed would help burn off any thing and lessen the smoke but it's still the same.
I spoke with the PO and he said that the spare pump that was in the trunk is the original IP and that he had installed the current one on the engine after it wouldn't start. He sold the car because he couldn't get the IP timed correctly to make it run
I am removing the current IP and will reinstall the spare one from the trunk to see if that has any effect on the smoking.
Another thing I noticed is that when stepping off the accelerator, drivingng at 50, with stick in the "S" notch, the engine makes a rattling noise, like the valves are knocking loudly. I suspect fuel delivery is the greatest part of the problem. I'll keep you posted on my progress.

Diesel911 · #33 06-01-2008, 08:48 PM

Sounds like you made some progress.

dabenz · #34 06-02-2008, 10:35 AM

BathCity, the starting time issue may be simple:
1) am assuming your compression numbers are good, indicating no carbon on valve seats. Valves adjust themselves tight over time - most valve adjustments are to loosen them up again.
2) am assuming your battery, electrical contacts, and starter are all good. Contacts clean-bright-tight, especially the grounds.
3) if your car has/had the gorilla knob then the start position puts the injection pump rack past full throttle position. If the gorilla knob has been bypassed then you may need to hold the foot throttle to the firewall when starting. I'm sure you know that you don't "pump" the foot throttle.

What's your fuel mileage and engine oil consumption? Driving habits?
Keep the engine oil below the halfway point on the dipstick to keep the rear crank seal from weeping too much?

I don't consider a bit of black smoke on heavy acceleration to be an issue on these engines. It's kind of like expecting a wind-up watch to be as good as quartz, for the same caliber of watch.

Also check the vacuum pump outlet hose. Oil there means fix the pump pronto.

Diesel911 · #35 06-08-2008, 10:45 AM

I Started a thread asking the symptoms of a govenor diaphragm problem and got 2 answers.
http://www.peachparts.com/shopforum/showthread.php?t=223548
Did you ever get an answer on the cost of the Diaphragem from US Diesel?

BathCity · #36 12-16-2008, 08:08 AM

Ok, I have now gotten back to working on the '74 - 240D. I plugged the block heater in and charged thre battery because it has sat since my last post due to work concerns. Due to the slump, I now have more time on my hands to get back to this car.
It started up, verry sluggishly, and of course smokes quite a bit.
I let her warm up to 175 degrees and then shut her down. Checked the oil, I had to much in her so I drained some and filled to the mid point between the dip stick marks. After restart, she still smokes. Here is a list of items I have done to get back in thew swing.

-Have reset pump timing to dead on 24 deg BTDC and double checked by when fuel just begins to well up in the #1 delivey valve, with spring and valve core removed.

-Pulled all injectors and put GM Top engine cleaner in the cylinders, then turned the engine over to clear it, then put in some more cleaner and allowed it to sit over night.

-Next day I again turned her over to clear the cylinders of the cleaner, put fresh in, and cleared MOST of it (yutned her over 3 times) then reinstalled the injectors. (Injetors have new nozzles of the correct type)

-Started the engine after purging fuel from lines to injectors. She started up immeadiatly, smoked like a banshe for a bit, but after a bit of run time she still smokes quite alot.

My question, is there supposed to be a sealing ring/o-ring of some sort in the injector itself?
I went to ********az and found a "Fuel Injector Seal; diesel injector holder O-ring seal" listed.
I spoke with the parts department at the local MB dealer and they can get a new IP pump diaphram for 60 bones. I have to wait until after the holidays to order due to funds.