Had installed six new glow plugs, new MAFS in the last four months. Ran fine, except for a little lag around 1,500 RPM.

Noticed a hard start problem when hot recently. Went to deaelr they had it for two days and finally said it needs a starting module $1,200.00 but it will continue to start. It will nor start eventually.

Left the garage door open a few nights ago, went down to start and it just cranked, almost started then cranked. Heated up the fuel lines, filter and block . After a few minutes it started, figured it gelled up.

Two days later went to start the car almost turned over then just cranked. Changed the filter, almost started then just cranked.

Can't seem to see any air in the clear fuel lines and car has plenty of fuel in it.

Glow plug light comes on normal and goes off normal. Could be a coincidence that the module went the same time I left the door open, I guess.

Any dieas?

Did the Dealer run a compression check? Low compression is one uncurable reason for poor cold starting.

Are you sure the glow plugs ARE coming and staying on--just because the red light comese on/off does not mean the glow plugs ARE heating. Turn on the dome light and even th eheadlight and watch their brightness. When th eglow plugs 'turn-off' , the other lights should greatly increase in brightness. If they do not change--suspect no current to the glow plugs.

What actual temps are you experiencing? Do you have fuel suitable for those temps? #2 is real marginal below 20F.

The fuel is treated. I did not think to check if the plug relay is working. That could be it. It went from hot start problems to cold start problems. It would start up in any weather until last week.

Glow plugs good

K40 relay, maybe.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Diesels are very reliable normally.

If the compression is up to snuff
If the glow plugs are heating up
If the injector pump is pumping

unless the injection timing has been badly screwed up--it WILL start.

Is it possible your fuel cut-off is remaining closed, not allowing fuel delivery?

Take some of the lines loose at the injectors amd make sure it IS delivering fuel.

Yeah, I know quite a bit about diesel engines. I own a construction company. Those diesels are a little less complicated then a these.

I hear the pump prime

The plugs are good

No air in lines

New filter

The first turn it always almost starts, then the rest of thime it just turns over.
No smoke or smell of burned diesel at all.

I'll try heating the block and filter again, thats the only thing I have not tried again.

Have you checked for OBDII codes with a codereader?

__________________
2005 Pathfinder LE
2001 E55
1998 M3
1982 320i

No but that's next. I did get her started with a tiny bit of ether. Didn't want to do it but it worked. Seems to be runnign well now.

I do notice some air in the clear fule lines near the filter. Only the one coming from the back side of the filter and the long one going to the bottom of the pump seem to have air. The rest are fine. Return lines maybe?

The OM606 engines do have fuel line problems!

ON that engine the fuel pump must PULL fuel from the tank into the filter & then finally to the pump. Any leak in that part of the system will make the engine very hard to start.....You won't have a fuel leak

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I would suspect the O-ring at the top of prefilter as the air leaker.

Thanks for the info fellas.

I am going to check the pre filter o-ring. although that is one of the lines that does not have air bubbles in it. Your saying there entering after the pre- filter I assume.

Doc,

Should I replace all the clear fuel lines? It has been starting normally since yesterday. Car has 80,000 on it.

Be sure it is cranking fast enough, slow cranking will keep a diesel from starting.

Also, don't use starting fluid with the glow-plugs. You can pull the glow-plug fuse and use starting fluid, and not ether, WD-40 makes good starting fluid (but lousy lubricant LOL), ether can cause all kinds of damage.

- Jeff Miller
190DT

On the OM606 engine we always replace ALL of the plastic lines, most of the time durning a GLOW plug replacement.. AT that time the intake is off & everything is easy to do. Line replacement will fix many starting & stalling problems. ALSO replace the pre-filter & it's o-ring as well.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks for the reply Doc. I going to replace the lines.

Jeff,

Just installed a new battery, this thing cranks as fast as possible. Very well aware of the ether and WD-40.

Thanks to all for the info.