Hard starting 1985 300D Help! Glow plug / Injectors .... - PeachParts Mercedes-Benz Forum

Hip001 · #1 09-09-2009, 09:58 AM

I've had this car 3 months now with very lil problems and 215k on the dial. Now it is hard to start. Turn the key on and off multi times and the glow plug dash light sometimes lights and sometimes not. And when lit it only stays lit for a couple sec.
I went by "diesel Giants" How to check/change Glow plugs. Only one of the 5 was under 1ohm. So I have a set ordered for pick up today.

My next question is injectors?
I am not sure of the complete service history of the car but it does seem to idle a lil rough. I watched a video clip on the same site and he said it should idle smooth like the example car did after installing "Bosio" injectors. Do you guys use these or the German OEM Bosch? How often should they be changed? I'm pulling them out tomorrow to go have them pop tested at the local shop. Also will running Bio B99 or Veggie blend affect/cause these issues?

Thanks again!
Hip

Hip001 · #2 09-09-2009, 09:59 AM

could either of these be why my MPG is low? I average in 6000 miles 23.8mpg.

kerry · #3 09-09-2009, 10:16 AM

Quote:

Originally Posted by Hip001

could either of these be why my MPG is low? I average in 6000 miles 23.8mpg.

Your mileage is not low, it is normal.
Glow plugs should fix your hard start issue.

toomany MBZ · #4 09-09-2009, 10:16 AM

Good for you having the injectors tested. That is the only way to know if you need new nozzles.
That is not terrible fuel mileage, as I understand it, there is less energy in some bio fuel anyway.http://www.biodiesel.com/index.php/biodiesel/biodiesel_benefits_why_use_biodiesel#power
That would mean lower mpg.

Hip001 · #5 09-09-2009, 10:26 AM

Quote:

Originally Posted by toomany MBZ

Good for you having the injectors tested. That is the only way to know if you need new nozzles.
That is not terrible fuel mileage, as I understand it, there is less energy in some bio fuel anyway.http://www.biodiesel.com/index.php/biodiesel/biodiesel_benefits_why_use_biodiesel#power
That would mean lower mpg.

I know this sounds funny but I have tracked the mileage every tank since I bought it(well 98% anyway) and the mpg straight diesel before any Bio was used was 23.1mpg for 2000 miles. Now since blending veggie and or running Bio the mileage has increased to 23.8mpg. Everything I've read said there should be a drop in mpg but my records say otherwise.
My cruising speed is usually 70-75 which is a lil past 3 on the tach. And my cruise is not working if that matters?

Muddin · #6 09-09-2009, 10:39 AM

I've read that worn motor mounts can give a rough idle. They are easy enough to check.

Diesel911 · #7 09-09-2009, 02:37 PM

I left someComments on Injector Nozzles in this thread today:

est injectors for a 617.952 engine

I have the Monark Spray Nozzles in my Mercedes and liked them enough I put them in my Volvo Diesel also. A good Quality at a reduced cost compared to the others.

The Bosch Nozzles have a feature that I do not like; The little pintel is central and cross drilled.

On my Engine Injectors and just about all of the Injectors I have pulled from the Junk Yard I found the Central Hole was plugged and some even had the much larger cross drilled hole plugged.

Bosio and Monark Nozzles do not have the Drilled feature.

Rebuilding the Injectors took out more of the shaking at idle than all of the other list of things I did.
Next most heipfule was adjusting the Valves; something that some members said also helped with the hard starting problem.

Hip001 · #8 09-09-2009, 03:34 PM

Quote:

Originally Posted by Muddin

I've read that worn motor mounts can give a rough idle. They are easy enough to check.

I did all the maintenance when I bought the car including replacing the motor mounts.

hopefully the pop testing will turn up something!

How often should I replace injectors and glow plugs?

kerry · #9 09-09-2009, 04:00 PM

Replace glow plugs when they fail.

Hip001 · #10 09-10-2009, 11:35 AM

bought Glow Plugs yesterday. Hope to install them after work today.
Also while there I'm gonna remove the injectors to have them pop tested.

Anything else I should do while I'm working in it?

toomany MBZ · #11 09-10-2009, 02:57 PM

Quote:

Originally Posted by Hip001

I know this sounds funny but I have tracked the mileage every tank since I bought it(well 98% anyway) and the mpg straight diesel before any Bio was used was 23.1mpg for 2000 miles. Now since blending veggie and or running Bio the mileage has increased to 23.8mpg. Everything I've read said there should be a drop in mpg but my records say otherwise.
My cruising speed is usually 70-75 which is a lil past 3 on the tach. And my cruise is not working if that matters?

Okay, a difference that small could be a number of things, don't worry about it, normal range.

Hip001 · #12 09-19-2009, 10:34 AM

I misplaced my 17mm wrench to remove the injector lines. So doing it the hard way moving the wrench 1/8 turn at a time. I only had enough time install 3 of the glow plugs. the car started up like new. Picked up the correct wrench at Sears the next day and finished the last two that night. Also removed the injectors and had them pop tested. If I understood him right they all were between 1825-1850(lbs?) except #2(counting fron the front). No2 leaked but he thought I damaged it removing it cause it looked like it leaked from around the return fitting. He had one we swapped it with. but he said they were all within specs. installed the injectors and it runs fine but still a lil rough at idle.