Hard Start - 204D

[tgr8Haus]

Hello,

I’ve been having a starting issue with my 1974 240d (automatic) and was wondering if anyone could point me in a direction.

Roughly a few times a week my benz has been having trouble starting. It turns over, sputters a few times, but does not immediately start. I have to go through 5 to 15 cranking intervals with the starter before it will start.

I’ve noticed that , when I’m having trouble starting, the low-pressure fuel system is void of diesel – I’ve popped the hood and tried to use the hand pump but it just pumps air. After a few rounds with the starter I start to feel the resistance – in the hand pump – of some fluid being pumped.

A few things I’ve noticed while poking around under the hood:
1) My hand pump leaks diesel when I pump it
2) The lines coming out of my injector are leaking a bit
3) My primary fuel filter has a small leak out of the top of bolt that secures it.

I plan on addressing all the issues above this weekend, but I’m unsure they fill fix the problem – With the exception of the hand-pump, they seem like they would affect the high-pressure system.

Any additional things I should be looking for?

[Govert]

Fuel tank filter is possibly clogged, so that the lift pump cannot pump fuel out of the tank. Check also the condition of the rubber fuel lines at the tank.

Replace hand pump with new one.
Replace fuel return lines.
Tighten bolt of fuel filter and/or replace washer.

If the low-pressure system cannot maintain the pressure, the high-pressure system will not be fed with diesel.

[Phillytwotank]

I wouldn't go to the tank screen at thi point. Sounds like a case of "loosing prime". Same course of action plus check ALL hoses and clamps.

[meltedpanda]

id start with the leaking hand pump -replace that and make sure all lines you see are not leaking

[tgr8Haus]

Thanks everyone! "loosing prime" seems like the magic combination of words -- I'll do some research online.

The wrenching starts Friday so wish me luck!