My '81 240D (about 150 K miles) has always started almost instantly. The other nite, it was hard to start, took many cranks to get it going, but once going, ran fine. Today it would not start period. Cranks strong,, but will not fire. Glow plugs test OK. 12 volts present at GP plug in relay. I cracked an injector line, no fuel. Changed the main filter (filled with diesel purge, power service additive and ATF) and it made no difference. Plenty of fuel in the tank. Twisted the little fuel knob on the dash in both directions, no difference. I took off the air cleaner and directed a flow of propane from a small torch into the intake, and it would fire for a few seconds and die out.



What could make this happen? Total almost sudden failure of the injector pump? How to diagnose? Thanks for any suggestions.

Shutoff valve or mechanism bound up and preventing starting?

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

Is there fuel in the primary/small fuel filter just before the injection pump, does it look clogged? Did you use the manual pump on the side of the injection pump (small white plastic knob) to bleed the system after changing the filter?

If it starts after bleeding the system it was either a clogged main filter or air is getting in the fuel system.

Good luck and keep us posted!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Leak or air bind in a fuel line?

Try taking the cigar hose off of the hard line and using the primer to pump fuel through and get the air out of the filters. You should be able to get fuel to pump through almost clear or very few bubbles.

If this is OK an you still cant get fuel at a hard line when cranking, maybe check out the lift pump.

__________________
CC: NSA

All things are burning, know this and be released.

82 Benz 240 D, Kuan Yin
12 Ford Escape 4wd

You're four times

It's hard to

more likely to

concentrate on

have an accident

two things

when you're on

at the same time.

a cell phone.

www.kiva.org It's not like there's anything wrong with feeling good, is there?

Most common problem with these cars. Very seldom is the injector pump itself involved as the actual fault.

Always change the secondary fuel filter first as you have done. Unless something else is obvious.

This scenario will eventually occur with all of them if the fuel system does not see maintenance. Periodic maintenance is cheap to do and pretty easy. A quick check every thirty thousand miles is probably enough. .

I define it as a fuel system tune up. Even the factory service manual advises it.

This drive it till it fails in some way costs power, milage and can have an impact on reliability. Also it shortens starter life and battery life by delaying the start up when the fuel system is in a sub standard condition on some examples.

This!




A very common cause for this situation would be a bad manual primer pump, which is suddenly leaking air into the injection pump fuel rack, which causes it to fill with air and lose its prime.


Try the test, and if the primer pump leaks fuel when you operate it, you'll need to replace it.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Plugged Fuel Tank Screen? When you loosen the Cigar hose to check the fuel flow when you re-install it swap the positions of the Cigar Hose and the Fuel Inlet hose where the tubing comes off the fender well. That will bypass the Fuel Tank Screen.

Some had said you need to have 1/2 tank of Fuel.

If you drive the Car like that and your problem goes away you know the than screen is plugged.

If the valves in your Fuel Supply/Lift Pump are worn the Fuel in the hose can flow back to the fuel tank and it takes a long time to get it back up to the Fuel Injection Pump when you try to start.
If pumping a lot on the hand primer brings fuel up to the pump and you start that maybe the issue.

Another way to test is to get a separated container with diesel fuel and get on the hand primer pump and then try to start and see if it will draw fuel out of the container.

__________________
84 300D, 82 Volvo 244Gl Diesel

The primary filter is full with one small air bubble as always. Incipient tank screen clogging does not seem likely, as i have to climb a steep hill to get to my house, and whenever i have had a partially clogged primary filter, that is usually when it shows up. The last trip up the hill was normal.



Tried propping the red emergency shut off back with a twig, no luck.


Pretty good fuel flow either cranking or pumping, from the end of the cigar hose taken off the hard line that goes back to the tank. 10 seconds of cranking yielded about an ounce of fuel.



So what does that leave? Lift pump? Where is that, and how do i check it?

Definitely got a flow from the cigar hose, primary filter full, propped the red emergency shut off way back, and still nothing!


What should i check next? Lift pump? Where is that and how to check?


Thanks!

https://www.peachparts.com/shopforum/diesel-discussion/107332-lift-pump-300d.html


https://www.peachparts.com/shopforum/diesel-discussion/107332-lift-pump-300d.html

__________________
CC: NSA

All things are burning, know this and be released.

82 Benz 240 D, Kuan Yin
12 Ford Escape 4wd

You're four times

It's hard to

more likely to

concentrate on

have an accident

two things

when you're on

at the same time.

a cell phone.

www.kiva.org It's not like there's anything wrong with feeling good, is there?

The manual primer pump has been leaking forever, especially when fully pumped, so i glossed over that possibility. But when i re-read all the posts, Maxbumpo's mention of the primer pump being a very common problem, i looked thru my parts stash, and found i had ordered a new one from Pelican a year or 2 ago, so i installed it, and changed the short bit of hose that goes from the primary filter to what i think is the lift pump, and for good measure circumcised the section that goes to the hard line from the tank. Pumped the hell out of it, and Lo and Behold, with a little initial roughness and 3 or 4 tries, the motor started, and seems to run normally, knock on weird!


THANKS AGAIN TO ALL WHO OFFERED SUGGESTIONS AND ADVICE!!