99 E300d hard cold stsrt
 

Have a new to me 99 that runs great, but it’s a real hard starter. New glow plugs, relay is fine, o rings were replaced on plastic lines. Injectors rebuilt, new filter. The prevailing theory is either air in the lines, which I can’t see, or a weak lift pump. My idea was to place an electric helper pump around 5 psi on the supply line just as it enters the engine compartment. Would this help me out?

Did you replace the shut off valve O ring as well? Does your car leak fuel at all?
A leaky shut off valve is known to do this.

Yep be sure the o-ring between the shutoff and the pump is good. Also don't forget the o-ring on the 'pool strainer' pre filter. If any air gets in the system on this engine, you are going to have a hard time. Get an LED flashlight and shine it behind the clear hoses and look for bubbles after it has sat. Park it nose up to enhance the process.

You may want to think about replacing the SOV due to age, mine had a crack in it, and it was leaking fuel out the connector.

How about doing the obvious first and check compression. If it’s good there is no need to jerry rig some home made solution.

Compression isn't the issue. My SDL has crap compression on two cylinders and it fires right up. OP claims it runs fine.

Now it’s missing on cylinder 5. Cracked lines to see which one and 5 makes no difference. Made a odd mechanical clatter and started missing after that. Is something ruined or just the injector?

Definitely fix all the fuel leaks first, Did you use the proper size and material o-rings on the fuel lines and change them all? Changing the delivery valve seals and shut off valve o-ring, fuel filters and the rubber line from the hard lines to the engine would help too. Get as much of it from the dealer as you can, trying to save a few dollars by not using quite the right part is basically installing an "unreliable beater" conversion kit.

Hold up OP. We need the WHOLE STORY. First you said it was running fine, now you say the engine is missing.

So the car all of a sudden developed miss?

Well people are telling me I don’t have compression on that cylinder based upon how it sounds on startup and to check valve clearances. Is that even possible on a om606?

Whoever said check valve clearances... ask them how you check the clearances on an engine with hydraulic lifters! :rolleyes:

How can someone also tell if it has poor compression without physically doing a compression test? :rolleyes:

Take a video and let’s see what’s going on