two (or more) trys to start/low power
 

So When I crank over my 83 300CD it often won't start on the first try. I let the glow plugs heat then crank and it doesn't usually start on the first try. Then off and back on immediately and it starts right away(without waiting for more glow .... like it isn't getting power to the spark plugs haha but of course it doesn't need power.
Sometimes especially when it is already warmed up, and after cranking it for a bit it does start on the first try... but then it barely runs, it idles down to around 500 rpm and floored... has half the power of a 240 .... or less. -like 5 minutes to get around the block!! Then I shut it off and restart and after one or more (lately much more) attempts it fires up like it finally got fuel and goes very very well.
I have searched a lot and not found anyone with the exact problem.
Could the fuel shut off thingy be sortta stuck???? And just where and how do I get to the fuel shut off thingy if that is it.
Please help my Family is making fun of my car:rolleyes:

Yes, it could be that the vacuum on the shut off valve is not releasing completely. Pull the brown vacuum hose off the shut off valve down between the end of the injection pump and the oil filter housing the next time you try to start it. If it starts right up, a non-releasing shut off valve is probably your problem.

I agree on checking the shut off first. If you feel it is probably okay close the return line from the injection pump off. You may have very little fuel pressure in the base of the injection pump.

Let us know if the close off changes the situation. If not you next want to see fuel flowing from the disconnected return hose but not full of air when cranking.

O.K. thanx guys this gives me a place to start:) So I will begin by opening the hood and taking off that brown line to see what I can learn. If it is a the shut off valve, do folks buy a new one or rebuild the old. And is it gonna be easy/hard........ cheap / expensive?
Thanx

Well I have been taking off the brown vac line that goes to the fuel shut off before starting the car, and it has been working normally. In fact today when I had driven it not long before and pulled the line off I was rewarded by hearing a little suction! So thank you folks I think we have it diagnosed.

Now to replace or rebuild... $100 seems excessive for a new one. as does $50 for a used.... but I will shop around I guess.
Since mine is sticking but not leaking maybe I can fix it...... Also I wonder if an alda adjustment that my son did might have affected it.... are they connected?

Leap not to that conclusion. The problem has not yet been isolated to the shut off valve. The problem is more likely the ignition switch. When you turn the key to 'run' it is supposed to bleed off the vacuum to the shut off valve. I suspect it is not, but more diagnosis is necessary. Put your Mity Vac in line with the shut off valve and watch it. What's the reading when the car is shut off. Does the line retain vacuum when the key is switch to the 'run' position? If so, the problem lies in the ignition switch. If the vacuum drops to zero in the 'run' position then something is amiss with the shut off valve. I doubt this is the case because I cannot recall reading of such a failure on this forum.

Thanx Kerry, I see what you mean, and how to test it. Thank you 4 taking the time to explain that to me. I will try to determine what's what tomorrow.