will not start after 25 degree day 77 240D - PeachParts Mercedes-Benz Forum

yoterbenz · #1 01-19-2009, 10:18 PM

Ok I'll lay down the facts...

Valves adjusted 2 months ago

New starter and battery

Glow plugs replaced with Monarch pencil types with heavier gauge wires connecting them

After some cold weather moved in I plugged in my car to ensure it would start in the morning. I did that for two days with success until I neglected to plug it in for one night. That was around Christmas and it still won't start.

I've pulled the glow plugs and put them on a battery charger and they glow nice and red. I reamed out the glow plug holes as best as I could. The carbon that came out was wet. I'm assuming this is caused by all the unburned fuel and cranking I've done in the last 3 weeks. I've checked the valve clearances and they are within spec.

I've tried starting it with starting fluid and that makes no difference at all. All the glow plugs are getting 11 volts and the glow plug light works like everything is fine. I've checked the strip fuse and all appears to be good. I've even gone as far as disconnecting the wire that is attached to the firewall that leads to the 4th glow plug. I bypassed the glow plug relay and strip fuse and used a Ford starter solenoid in it's place. The plugs were getting the correct voltage and that didn't work.

I've even gone to the lengths as making a seperate tank via dieselgiant's method of purging the IP and used diesel in there and nothing. I've replaced both fuel filters and I'm at a dead end.

Nothing I've done seems to make any bit of difference. It just cranks and cranks until I need to charge the battery back up. Any help would be appreciated. I'm about to push this thing off a cliff. Oh and BTW everything was working great until this cold morning. Mileage was good and burned oil like an old diesel does. I'm at a loss.

kerry · #2 01-19-2009, 10:24 PM

Time to do a compression test.

coachgeo · #3 01-19-2009, 10:49 PM

Rent a kerosene turbo heater and then go get some ducting tube from a heatingAC place. A good 3 or 4 feet of it. Blow hot air from turbo heater thru the ducting and under the car. Start by fuel tank

Then front of car and radiator. (put it up on some cement blocks if you need) Watch it to make sure heat is not affecting plastic parts.

My bet is then it will fire up.

then go get some anti gell (power service diesel clean?)

Other Options.

Few hair dryers in the engine comparment. Lay blacket over the top to hold heat in.

hair dryer, heat gun and take your time to warm the fuel lines back to front

Electric blanket under the hood. Loosly close hood. Dont let it press on blanket. Another blanket on top to hold heat in.

sterno under the fuel tank. blankets or tarp help hold heat in

ALL OF THESE..... stick around and watch the car like a hawk. check things out ever once in a while to catch anything on it's way to becoming a fire starter.

coachgeo · #4 01-19-2009, 10:52 PM

oh.... and spray the glow plug relay ends with electrical cleaner spray.

Cold loves to enhance any loose/poor/Dirty connections. Turns them into NO CONNECTIONS

strelnik · #5 01-19-2009, 11:01 PM

Quote:

Originally Posted by kerry

Time to do a compression test.

1. I second the motion!

2. Besides, how "cold" is cold weather? My car starts w/o problems in 0 degree weather tho I am careful to glow plug it a long time in advance of the one and only start I try.

3. What kind of fuel are you using (summer/winter/bio/dino) and are you sure it's getting there?

4. Before you spend money, do some more testing, please. Do a CSI on the car before you determine cause of malfunction, it'll save you time, money, frustration. I have learned this the hard way.

Good luck,

s

yoterbenz · #6 01-19-2009, 11:37 PM

Quote:

Originally Posted by strelnik

1. I second the motion!

2. Besides, how "cold" is cold weather? My car starts w/o problems in 0 degree weather tho I am careful to glow plug it a long time in advance of the one and only start I try.

3. What kind of fuel are you using (summer/winter/bio/dino) and are you sure it's getting there?

4. Before you spend money, do some more testing, please. Do a CSI on the car before you determine cause of malfunction, it'll save you time, money, frustration. I have learned this the hard way.

Good luck,

s

Fuel is regular ULSD pump diesel. I have about a half of tank in there. If you read the post I thought it was a fuel prob at first so I made a small tank out of a plastic bottle. I ran a line from the lift pump to the bottle and routed the return line there as well. Filled it with fresh diesel and nothing. As far as CSI I thought I've covered almost everything. Still lost..

yellit · #7 01-19-2009, 11:41 PM

Sounds like you got the electrics ruled out.....

Might want to meter the fuel pressure betweeen the spin-on filter and the IP banjo fitting to rule out low supply pressure to the IP...need at least 7 to 10 psi from lift pump & no air leaks ....

Actros617 · #8 01-20-2009, 12:37 AM

Get some Diesel 911 works really good!!! Open the fuel filter, try to pour out half of the fuel in the filter and fill it up with Diesel 911, It always gets my 300SD starting in -10 *F

whunter · #9 01-20-2009, 01:53 AM

Quote:

Originally Posted by yellit

Sounds like you got the electrics ruled out.....

Might want to meter the fuel pressure between the spin-on filter and the IP banjo fitting to rule out low supply pressure to the IP...need at least 7 to 10 psi from lift pump & no air leaks ....

I no longer check it, rebuild the lift pump MB# 0000900210, cold weather causes issues with the old valves.

Note:
If there was carbon built up on the exhaust valve seats when you adjusted them, two months of driving would have broken it away = the exhaust valves may be too tight again = compression loss.

You can read the following thread for more data.
Valve adjustment OM617 FYI.
http://www.peachparts.com/shopforum/showthread.php?t=107729

If the fuel has jelled inside the injection pump, compression bore/delivery valve will be plugged/gummed = no fuel flow/lubrication.

Note:
99.99% you can put it in a heated garage at 70F with doors, hood and trunk open for 2 - 3 hours, then start the engine.
Disconnect battery or courtesy lights could drain it.

You can lower the jell point of diesel with Kerosene, +35F to +1F one gallon for a full tank, -1F to -40F two gallon for a full tank.
Please be aware thinning the fuel makes it easier to start, and reduces MPG.

A link that will help you.

Cold weather starting links
http://www.peachparts.com/shopforum/showthread.php?p=1018529

Have a great day...

yellit · #10 01-20-2009, 01:55 AM

Crack open the injector line nut on each injector to see if fuel is coming from each IP delivery valve...See if they all output about the same....this would confirm IP cam is turning & fuel is pushing through the metal feed lines....

A recent thread discussed IP snout key shear off... resulting in no IP function.....

kerry · #11 01-20-2009, 10:08 AM

Please don't take this as an insult, but you did remove the ground strap from the plug at the front of the engine when replacing with pencil plugs right?

yoterbenz · #12 01-21-2009, 12:20 AM

Quote:

Originally Posted by kerry

Please don't take this as an insult, but you did remove the ground strap from the plug at the front of the engine when replacing with pencil plugs right?

Well lucky for me the previous owner squared that away for me. When I bought the car I wasn't nearly as educated as I am now about the good ol W123's. Dont worry I didn't hook up that ground strap. Parallel and series two different beasts

Thanks for the concern.

moon161 · #13 01-21-2009, 10:48 AM

You should get decent cranking rev's at 25 F unless battery or starter is bad. You are not gelled at 25F.

Feed the inlet with hot air from a hair dryer while someone else cranks.

Mr.Kenny · #14 01-21-2009, 10:54 AM

Tow that car down the street in 2nd or 3rd gear (ignition on).

If that don't get her started, there are other issues.

Graplr · #15 01-21-2009, 11:15 AM

The first winter I drove a Mercedes diesel I did a valve adjustment right before winter came. I didn't pay close enought attention to the order of exhaust-intake and just assumed it was E-I-E-I-E...etc (everyother). My car wouldn't start below 25F without being plugged in. I barely made it through the winter with the car. Springtime I decide it is time for another valve adjustment. I look a bit closer at the diagram and see it is E-I-I-E-E-I-I-E-E-I. Duh, my valves clearances were backwards on some.

So dont' take this the wrong way, but just make sure you are doing your measurements and tests the correct way.

If you 100% confident everything (GP, battery, starter, valves, fuel, IP, etc) are good. Then yes, it is time for a compression test. A decent engine properly tuned should start at that temp.