Acting differently @ startup - PeachParts Mercedes-Benz Forum

JimmyL · #1 07-29-2004, 12:00 AM

Upon searching 'rough idle startup' and other variations, I'm still not sure of my best starting point.
'80 300TD. Been running well, and has always started right up. Having a little problem with my glow plug relay, but it works most of the time. Ohmed my glow plugs, all were .7 ohms. All that aside....
The car fires right up, runs for half a second, then acts like the gas is just shut off, sputters and either dies or shudders horribly. It then idles up OK and runs like it always does, which is fine. It only has this problem at startup. I also have notice that the front 2 injectors always are covered with fuel, while back 3 are always dry. I am going to replace the return lines for those 2 injectors to see if the fuel is coming from there, or from injector itself.
Should I go filters first? If injectors ARE leaking how exactly should I proceed. Does the fact that it only happens at startup after car sitting for a little while point to something specific? Valves just adjusted a couple of weeks ago, by the way. This is my daily driver work car, so if I need to remove injector/injectors and let them soak in 'caustic' carb cleaner (ala Larry Bible post) I have to plan ahead.
Do the injectors themselves leak, or do the 'sleeves' they seem to screw into leak?
Lots of questions, I know.
Thank yall,
Jimmy

JHZR2 · #2 07-29-2004, 05:43 AM

I have the same issue, ever since I did my last valve adjustment. Ive checked and then triple checked everything since, and its all within spec.

I think it might have something to do with the fuel, as when I added a heavy dose of redline, it went away. But typically it resembles how it would start on a cold day, after sitting for a long time; and similarly, if I press the pedal ever so slightly, it starts perfectly.

Its very annoying, rather intermittent, and I wish it wouldnt be like this.

I hope for suggestions,

Thanks,

JMH

leathermang · #3 07-29-2004, 07:44 AM

Guys, I am not sure on this... but do a search for rack damper adjustment ....
There is an adjustment on the back of the IP on some cars which MB engineers anticipated might help AFTER the car got older....
Check also the titles of tech bulletins for your specific car at ALLDATA.com
That is free... see if anything which sounds like your problem/with fix is listed there...

JimmyL · #4 07-29-2004, 08:39 PM

What are the wrench sizes on the injectors? Do the sleeves stay in place when injectors are removed? I replaced the return lines tonight, and will monitor for leakage.
In my search I saw some posts on testing the spray pattern of the injectors. I just wanted to test my understanding of what I read:
I take out one at a time, protect my eyes, put cardboard or something under injector and start car??? I then check for a spray pattern and not a drip?! Am I correct? How long should I let the car run? I'm assuming this will be on and off pretty quick.
Thanks so much.
Jimmy

leathermang · #5 07-29-2004, 08:54 PM

The manual shows a manually operated deal where you take the injector out and use the hand pump .... which also has a pressure guage.... and you press down and see not only the spray pattern....but the pressure at which it lets go... both are important....
If you do it with on the engine I suggest you place the injector where it is pointing into a jar and cover it as well as you can... it may produce a lot of diesel vapor....