79 300 sd, hard to start..HELP - Page 2 - PeachParts Mercedes-Benz Forum

kerry · #16 09-20-2007, 09:56 AM

Depending on why the compression is low, the fix is either simple or a death knell. Can you post the compression numbers?
If the problem is maladjusted valves, the solution is valve adjustment. This is simple and inexpensive. If the problem is burned valves, solution is more expensive ($2k or so). If the problem is worn rings, the solution is much more expensive and depending on the condition of the car, possibly not worth doing.
Without knowing the exact compression numbers, it's hard to diagnose.

linda ann · #17 09-20-2007, 10:48 AM

Quote:

Originally Posted by rs899

No, oil pan gasket and oil leaks have nothing to do with this.

You are giving us tidbits of information. It is a lot easier to help if we know the whole picture.

1. How many miles are on this engine? Does the car burn a lot of oil ( a lot of blue smoke)? What has been the history of the starting problem? Has the car gotten progressively harder to start over time, or was this a sudden problem? Is the starter spinning quickly?

2. How did you test the glow plug system? What did you check? In an earlier post you noted problems with what seemed to be the relay....

3. What are the compression readings? How did you test ? Have you adjusted your valves to make sure they are in spec ( and closing at the proper time increasing compression)?

4. How many times have you had to use ether to start the car?

Rick

iv'e had car 2 years, never adjusted valves, so will take care of that this weekend, a friend is coming to do a compression test, will let u know, glow plugs tested and are fine..were tested w/a multimeter. car does not burn oil, but when cold has black, black, smoke/almost soot like, and if car is not started again within 3 hours it requires ether to start, if it's warm outside one quick shot will do it, if it's below 60 degrees forget it, i just wait for it to warm up. I LOVE this car and want to make it work!! so any help is GREATLY appreciated.

vstech · #18 09-20-2007, 11:00 AM

first, DO NOT USE ETHER IN OLD DIESELS!!!
if your car has been started with ether for a while, it's pretty sure to have valve/piston damage. also, the Prechamber atomization ball could be broken.
if it were me, I would pull each glow plug, and connect each one to power and verify they heat up. next I would pull each injector (you will need to order a set of heat shields first!) and look in the PC for damage with a flashlight. look for carbon gunking up the holes, and look for the ball to still be attached to the rod.
if you need to spray something into the intake to start the motor, use WD-40 it will do the same thing, but not damage stuff.
where are you spraying the ether in? are you pulling the air cleaner cover?
you say you have a new battery, how new? mine has over 350K on it, and it will start in 0°F weather without a glow.
you have checked the gp's with a multimeter as described on DG's site? have you verified 12 volts is making it to the plugs?
2 years may or may not be a long time, it depends on how many miles you drive. it's good to adjust the valves every 15K.
when you start to adjust the valves, if you pull the injectors and lines, it is really simple to get the wrenches in there for valve adjusting.

linda ann · #19 09-20-2007, 02:11 PM

Quote:

Originally Posted by vstech

first, DO NOT USE ETHER IN OLD DIESELS!!!
if your car has been started with ether for a while, it's pretty sure to have valve/piston damage. also, the Prechamber atomization ball could be broken.
if it were me, I would pull each glow plug, and connect each one to power and verify they heat up. next I would pull each injector (you will need to order a set of heat shields first!) and look in the PC for damage with a flashlight. look for carbon gunking up the holes, and look for the ball to still be attached to the rod.
if you need to spray something into the intake to start the motor, use WD-40 it will do the same thing, but not damage stuff.
where are you spraying the ether in? are you pulling the air cleaner cover?
you say you have a new battery, how new? mine has over 350K on it, and it will start in 0°F weather without a glow.
you have checked the gp's with a multimeter as described on DG's site? have you verified 12 volts is making it to the plugs?
2 years may or may not be a long time, it depends on how many miles you drive. it's good to adjust the valves every 15K.
when you start to adjust the valves, if you pull the injectors and lines, it is really simple to get the wrenches in there for valve adjusting.

thanks, will check to see if gp are getting 12 volts, battery is 1 yr old, but car has rarely been driven due to this starting problem. yes i do pull the air cleaner cover, but i will use wd40 if it does the same thing, i had never heard of that. looks like i have my work cut out for me, i only hope no real damage has been done, thanks, i will check back. linda

Wodnek · #20 09-20-2007, 04:19 PM

Quote:

Originally Posted by linda ann

ok... glow plugs are fine..compression is the problem, where do i start, how costly is this and is it a diy project? or is it time to start parting out my baby???

thanks to all!!!!

If the car is in good shape and you determine an engine overhaul is in order, it is NOT time to part it out. It is time to look for a rust bucket with a good engine that can be swapped.