Om606 difficult to start in cold

[jake12tech]

It has one bad glow plug in it (broke in the head). If it sits overnight and for maybe about 8 hours in 35 degrees or less, it is damn near impossible to start without needing to throw a jump box on it. Is the one bad glow plug enough to throw it off this bad? I ordered a block heater cord for it. This is the first year in PA I’ve ever had an issue starting it and I’ve been running it off 5 plugs for about 3 years. 227k miles, running Lubromolly synthetic oil 10w40 (mb spec sheet approved).

[jake12tech]

BTW, all the fuel lines have been replaced and updated. No air or leaks anywhere.

[Usaguy]

What's the state of your injectors?

[Murkybenz]

I had a dead broken plug on mine that I could not remove and it would still start ok at those temps even on 50/50 veg and diesel mix, you probably have another couple of dead plugs or possibly internal breaks in the glow relay outputs.

Video shows broken outputs and how to fix
https://youtu.be/D8YIfvHnHnw

[pimpernell]

Originally Posted by jake12tech

It has one bad glow plug in it (broke in the head). If it sits overnight and for maybe about 8 hours in 35 degrees or less, it is damn near impossible to start without needing to throw a jump box on it. Is the one bad glow plug enough to throw it off this bad? I ordered a block heater cord for it. This is the first year in PA I’ve ever had an issue starting it and I’ve been running it off 5 plugs for about 3 years. 227k miles, running Lubromolly synthetic oil 10w40 (mb spec sheet approved).

Is it possible that another glow plug has failed?? My 96E300d had one bad plug, and it started in 15 degree temps in Jersey on a regular basis. It took a little bit longer than usual, but it did start. My car had 130,000 on it at the time, and the battery was about 2 years old.

[Diseasel300]

In addition to checking for additional failed plugs as others have mentioned, you might check for voltage at the glow plugs. It's possible the glow plug relay is packing up or has a connection that isn't being made when it gets cold.

You're *CERTAIN* there's no air in the fuel? Tank vent isn't blocked and pulling a vacuum on the fuel system?

Lastly, I'll kick that dead horse - but how's your compression?

[shertex]

Should start fine with only one bad plug....did that through a New England winter (maybe two?) on my 98.

[jay_bob]

I will throw out there again that I have the complete Baum tool set, complete with a Time-sert kit for repairing the head threads, for drilling out stuck OM606 glow plugs, pm me to set up borrowing it.

http://www.peachparts.com/shopforum/diesel-discussion/397076-om606-glow-plug-change-one-broke-off.html

[jake12tech]

Thanks folks for the response. I got 227k on original injectors no smoke yet. Good compression, afaik. The engine has been HIGHLY maintained. Synthetic oil changes every 3k and fuel filters every 6k miles.

Jay Bob, I will be in touch with you this spring. I’d like to wait til we get out of this 20 degree weather in pa. I really miss having my lift at Mercedes with a heated shop. But career paths changed.

[Usaguy]

Originally Posted by jake12tech

Thanks folks for the response. I got 227k on original injectors no smoke yet...

You should at least check them for spray pattern because if they don't atomize properly then that will affect cold starting

[jay_bob]

Sounds good. You would be surprised how much better it will run with refreshed injectors.

I would plan on pulling the injectors and sending them off to Greazzer and have him rebuild them while you're doing the glow plug work.

[jake12tech]

Jay Bob, I absolutely agree. That is the plan.

We’ll update, as much as I really felt otherwise. There’s air in the lines somewhere!!! It died last night at 1am and wouldn’t reprime this afternoon. I am going to install an inline electric lift pump til the weather clears up. That should bypass the issue of no prime correct? My plan is turn it on before the car runs and keep it on while running so it doesn’t die.

[83w126]

Is the shut off valve o ring new too? Those needed replacing regularly (every year or two) on the one I had, it's an easy job though.

[ds190]

I use the block heater with a lamp timer and extension cord for my E300. I let the heater run for 3-4 hours before starting in the morning. And, instant interior heat in the cabin!

I also go through glow cycle twice, and then the third time start the engine.

Make sure your battery is in good shape. I have a trickle charger on it over the weekend.

[Diesel911]

You might want to look at a thread on rebuilding the Fuel Supply/Lift Pump and see the symptoms that caused the rebuild.

Personally I think injector nozzles are good for about 125-150 thousand miles before they are worn out. They certainly should be at least checked by that mileage.