Hi All - this topic has had many suggestions - but no cure yet.

98 E320 97,000 miles when purchased, now 135,000. Have not resolved long cranking since purchase 24months ago! Prior to purchase I had MB dealer do a pre purchse inspection.

Was told changing spark plugs would take care of problem.

The sympotoms are irregular, in that: On Cold starts (first start of the day) sometimes an immediate start (normal), other times, cranks for 5 secs prior to starting. On starts within 10 minutes or more after shut down, almost always a normal start. After 10 minutes, irregular starts, some normal, some not. Car rarely sits from Friday to Monday, but when it does it often has an immediate start.

6 or 8 times across the last 24 months when starting after long (5 sec) crank; a mis-fire on cyl 3 code was thrown, car would ran rough at idle without smoothing out. Shut down car, restart and runs smooth at idle.

Car runs normal through driving power range, and never dies, 23 City MPG, 28+ Hwy Mpg.

What's been done:
Jan 12 Plugs were replace with OME plugs purchased from dealer.
Oct 12 Fuel pump, filter and relay - OME replaced by indy.
Nov 12 Replace No 3 cyl coil with Bosch and new MB spark wires on cyl 3. o
Dec 12 Crank shaft position sensor replaced with Bosch sensor
Apr 13 Ran Seafoam Injector cleaner at double strenght thourgh 4 tanks of gas at indy's recommendation.
May 13 Replaced Mass Air Flow sensor Bosch.
Nov 13 Replace Camshaft sensor - OME.
If the problem is a leaky injector: With cyl 3 always throwing the mis fire code, it seems that would be a likely culpert. Any reason to not to replace one injector rather than all 6?
I witnessed the fuel rail pressure test before and after. Pressure dropped like a rock immediately on shut down. With fuel pump, filter and relay replaced, the rail held pressure.

Out of ideas and money!! &

Hook a light directly to the fuel pump and make sure it turns on every time the car is cranking. ( Put the light across the fuel pump terminals not to body ground and one terminal. )

Problem resolved. Replaced injector on cylinder 3. Everthing back to normal!

How did you track it down to that?

You only replaced cyl #3 injector and not the rest? Why not just do them all now and not have to worry about the rest later? It's about time anyway.

__________________
Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Jeremyparr/Jake121tech,

How did I track down? Only know of three sources of loss of fuel pressure. Bad pump, fuel line leak or leaking injector(S). The pump was replaced, no leaking fuel line - only injector left. When I did get misfire on cyl 3 code, engine would start as if flooded, rough at idle, then clear it's self. My reasoning was it had to be a leaky injector, most likely cyl 3!

As too why I only replaced cyl 3. Because one injector failed, their is no reason to believe the others are about to fail, this is not a maintenance part. I've owned many cars with electronic fuel injection, this is the first failure ever. Firm beleiver if it ain't broke, don't fix it, no point in throwing good money after bad.

FYI
This was first time I've changed out an electronic injector, process pretty simple once I figureded out where everything was located. Pelican parts has a nice procedure written up. Word of caution - replace all injectors with new O rings to avoid gas leakage[/B].