Loss of Power Problem -Q #2- Diesel: 300TD Wagon (European)?

Question

I have a loss of power problem that is worse when the car is idling and first starts up. I also have a bad shake when idling. Sometimes this shake is forward and back and sometimes it is left to right. I also have a lot of smelly white smoke when starting up and idling.
I've had the fuel injectors replaced (non-mercedes injectors - should I change them to mercedes parts?)
I've also replaced the fuel injector pump. After this was installed the car still had the shake sometimes but the power was great and there was no white smoke. It was fine for 50miles and then it was back to normal.
My mechanic wants to now:
change the head gasket
valve cover gasket
camshaft
valves
and filters
After reading other posts maybe he should also do this:
Diesel Purge- run through injector pump
ATF - quart (only do sometimes- or will clog injectors)
use Mobil 1 SYN or run DELO 15W-40 oil
Change Transmission filter
use transmission fluid = Mobil 1 75W-90

Anyone have advice on order of troubleshooting?

Answer 1

first off i suspect an air leak in the fuel lines [intermittant shaking especially when and just after starting] [check supply hose where it comes out the bottom of the tank or at transfer pump.[presupposing the glow plugs are all working properly]

also suspect that replacement pump is not in proper time and recc. this to your local mercedes dealer [the timing chain may need to be replaced, if stretched] to get everything exactly where it needs to be.[ this is a long, long chain and a little stretch at every link adds up to a lot of stretch overall.late pump timing can cause white smoke


normal compression pressures for this engine are 400 psi or better[370 -400 ok] if lower and valves are closing [004int and 013 ex] suspect valve job nesessary ,expect worn guides on this engine.and inspect plunger for tensioner while cam cover is off if 13mm [about 1/2 an inch] is exposed it's time for a new chain

head gaskets don't normally blow on these engines[116-117] even after a massive overheat, it's been rare


as for the camshaft i've only seen one in 20 + years that had a wiped lobe [car had been mis-serviced for years by savages]

remove vac line from transmission modulator if you see trans fluid run out replace the modulator,.normally when bad it wont make rough running or smoke but shifts will be poor quality.

pop testing the injectors would be a good idea but probabley is not the culperit here
i hope this has been helpful good luck

Answer 2

Fuel injectors are Bosch no matter where they come from. Even new from the box, it's a good idea to bring the set to a Diesel specialist and have the spray pattern checked and adjusted as JP suggests.

Forget the synthetic stuff. Synthetic oil's only use in this engine is to ease starts in sub zero cold weather. Otherwise, it's a total waste. There's so much blowby soot produced in this motor, you have to stick to the standard change schedule, even with synthetic. So 11 months a year it's a waste.

I find that Mobil 1 transmission fluid makes for rougher shifting in the older Benz's. I think the fluid tends to foam, or maybe it doesn't have the right friction modifiers. If you have an automatic, you would use ATF, not the heavier gear 75W-90 gear oil. Changing your transmission fluid is a good idea, but I doubt it has anything to do with your rough idle.

ATF in the fuel, or any other light oil sometimes helps, but only if the problem is related to sticky components in the pump or injectors. Since they're new, I don't think this will help. Same with Diesel Purge. These steps can't hurt, but I'm not hopeful.

White smoke isn't fuel, which would show black. White smoke sounds like water. Coolant can get into the exhaust from a bad head gasket, so your mechanic may be on the right track. If he changes the head gasket, the other items should be checked and replaced as needed, at the same time. But before he dives in, there are a couple of cheap diagnostic tests that should be done. These include chemical analysis of your coolant, to see if exhaust byproducts have become mixed in. And the other test is a leakdown test, to see if the cylinders are leaking, and if so, from where.

One more thought...are you buying your fuel in the same place all the time? It may be that some water has seeped into their tanks, and is being pumped into yours. If this is the case, the water may have damaged your new injectors. Switch suppliers, and have your injectors checked again.

Answer 3

Find a mercedes benz technician that can test the injectors spray and break open pressure. We do this with a bench mounted aluminum can and hand pump device with a pressure gauge on the pump shows what the opening pressure is and if the aftermarket injectors are seeping not fully closing. Roughness while the engine is cold might be worn out glow plugs. Replace the injector shields each time in the injector holes. The other thing is costly carboned up precombustion chambers. Secret to 300sd Turbo diesels is to open them up allow the engine to work hard to keep carbon from forming at low speeds.

Answer 4

Your white smoke at start up is unburnt fuel. The rough running is due to cylinders not firing. Maybe you should try a new set of glow plugs before tearing your motor apart, as I did ,once,a long time ago. Did the valve job and still it started rough,with white smoke. Ran fine after only a few minuets. Changed out glow plugs and the problem went away as well as the car.

Answer 5

If your mechanic wants to change all this to solve your problem, then either you have a car that is in poor condition or you need to find a mechanic with better diagnostic skills.
You mention that you have a turbo diesel, out Here in Australia, some, not all merc turbo diesels had turbo problems, seek out a turbo specialist and get him to take a look, also what does the smoke smell like. have you been getting poor milage out of a tank of fuel or are you low on oil or water in the radiator. is there any oil leeks under the car?
all these questions have to be asked before any diagnosis can be given, even over here at yahoo.

Answer 6

Sounds like trash in your tank has made it passed the filters.Drain tank,and give a good cleaning.Clean screen too.Blow steel fuel lines to the tank out.Run a purge after assembly.At least run one gallon biodiesel to kill algae.