starting problem 83 300D

[frauke83300D]

I bought this 300d to fix up..owner said that it would run for 5 mins then turn off..he said it was locked up..but it 's not..the engine turns fine but will not fire up..I change all the glow plugs,checked the g/p timer..the alda swithover has been bypassed...there is no fuel spray at the injector connection fuel line when removed..only a drip...the primer leaks when I try to prime to remove the air...getting a new one 5/3/07..could the shut off valve be engaged even though the mechnical arms work fine...with the alda switchover bypassed..is there a resent if the pressure got too high..how long after u prime will the fuel spit out at the fuel injectoer connection......thanks from a newbeeee..

[AnthroProfessor]

The primer pump should not leak. I hear they are a replaceable unit.

Is fuel getting into the main fuel filter? Are both filters new?


If yes, then I guess your problem is the metal fuel pipes that go into the injector nozzles. The way the fuel moves through that area is if the injector is working. I guess you are going to have to let the starter turn the engine for you several rounds while someone loosens the pipe going into the injectors. A half turn on the nut towards unscrewing it while the engine turns, should deliver good enough fuel.

You see, with fuel already going into the main fuel filter, the next step is the injector pump delivering fuel to the injector nozzles. The injector pump must be turning over in order to force fuel into the injectors. Without the turning, the injector pump cannot do its job.

BUT WAIT.........

With the fuel being pushed where it should and still no start, then it could also be the timing of the engine is off. It would need to have the head taken off and valve job performed on it by a machine shop.


OTHER POSSIBILITY.....

The injector pump may be defective and requires a rebuild. While this is very rare, it did happen to one of my cars. The engine would turn but no start. It was later diagnosed that the injector pump needed a rebuild. I was asked how the car behaved days before the breakdown. I told them that I felt it was kind of weak. The engine felt very weak. BINGO they said. That is the indication the injector pump was ready to die.


I had all three of the scenarios mentioned happen to me. I hope your problem is as simple as the first remedy mentioned.

[Maxbumpo]

Fix the priming pump first; if it is continuously leaking air, you may never get the car started.

The priming pump only pushes fuel through the pump and the filters, it does not push fuel out the metal lines to the injectors.

Once you've operated the pump 50 to 100 times, the sound will change to more of a whistling sound when the system is primed. Next you will need to crank the engine over with starter for one or two minutes to get the fuel out to the injectors. Only a small amount of fuel is pushed to each injector when starting, really only a drip-drip, not a squirt-squirt.

You may need to pull start the car; procedure will be in your owner's manual (including for automatic transmissions).

Would be worthwhile adjusting the valves first, and checking the timing chain stretch while you are there (would reveal if chain has jumped).

[frauke83300D]

thanks for the insight....if I do a compression check would this not tell me that there is enough compression to fire up....and then do that fuel injector pump timimg thing...per the mb book..so that the fuel and compression on target to start...thanks

[Don350SDL]

Read the answer again. If there's air getting in, air doesn't burn, so fix that first. Once you get fuel (instead of just air), then you can start with the rest. And maybe it'll just start up.

[frauke83300D]

thank you will try the primer when it arrives...we keep u posted

[Maxbumpo]

thanks for the insight....if I do a compression check would this not tell me that there is enough compression to fire up....and then do that fuel injector pump timimg thing...per the mb book..so that the fuel and compression on target to start...thanks

Don't waste your time with a compression check; either the car will start or it won't. Do adjust the valves; they require adjustment every 15k miles, and if they get too tight they will cause a 'no start' condition. Check the condition of the timing chain (measure the stretch) when you have the valve cover off. Once you have adjusted the valves, installed a new primer pump and system primed, and a well charged battery, you may want to plug in the block heater for an hour before attempting to start. If the battery/starter won't do the job, use the pull-start procedure in your owner's manual. Quite often, when a car has been sitting for many years and won't start, this is the only way to do the job...

Don't worry about timing the injection pump UNLESS you have evidence that someone has moved it. If left alone, the injection pump will hold its calibration for the life of the car! It is NOT required to be tested and adjusted as a matter of routine maintenance. Timing the injection pump would be among the last things to try.

[frauke83300D]

thank you...

[Maxbumpo]

Last caution: Do NOT use ether to try to start the car, or you may destroy the engine. Ether should never be used to start an indirect injection diesel engine.

[frauke83300D]

pull the 300D per the owners manual..started but stopped....pulled again and got one little sputter....took the car home tried to start via the battery..no go.....
today was going to push it into the garage...I said let me check the battery..turn the car on gloe light went out turned the key...it started...what the heck..let it run for a few minuties..it has a knocking noise in the top end,,,idles fine...started it twice ..started both times....now going to take off the valve cover to inspect what is make the noise....thanks

[Maxbumpo]

Diagnosing noises from an MB diesel engine of that vintage is largely a useless exercise, unless the noise comes from an external component like the compressor or alternator or a rattling air cleaner.

Some nailing/knocking at idle and maybe even up to 1500 RPM is to be expected for your car, until you have caught up all the deferred maintenance (like adjusting the valves - have you done that yet?), and run a few tank fulls of good clean fuel. Driving the car hard or for extended periods on highway will speed up the process. A fuel system cleaner (Lubro Moly Diesel Purge and Chevron Techron are the best) can help, as will using a synthetic oil like Moblil 1 which has cleaning properties to remove carbon deposits in oil rings.

[frauke83300D]

I am going to take off the valve cover tonight to see if there is anything flopping around that should not be.....then adjust the valves and then do as you have suggested to clean the fuel system...thanks for your insight and help..will keep you'all posted..thanks

[Maxbumpo]

Don,

Very glad to know that you've got her running.

Do let us know how it turns out. Hope you check(ed) the timing chain stretch while you were there...

Have you thought about joining MBCA? I see you are in NC - very active section up there. Also, MB's annual technical extravaganza will be in Reston VA in just a couple weeks. Consider the discounts at dealership, and supporting this website that has helped you. Between the two, if you turn your own wrenches, you will probably save thousands and thousands of dollars and enjoy many years of MB ownership.

[frauke83300D]

well took off the valve cover started it up....and found nothing flopping around..nor loose..plenty of oil coming out and on the shop floor too...sounds like a thrown rod bearing....can I get access to the crankshaft whilr the engine is in the car by removing the oil pans...to check for bearing play...thanks for the va club info...thanks