Working my way through a no start issue. Stalled at a light 2 days ago and would not start back up. Mid day traffic, 75 degrees, all fluids ok, no notifications on message panel. It just choked out and had to be pushed off the road. At first check of the fuel pressure there was enough pressure to spray mist out of the schrader valve. Fuel pump priming as usual (I think - about 3 seconds on key position 2). Changed out fuel filter after pulling the pump and finding the tip of a ball point pen inside the pump assembly cannister. Thinking there must be the ink somewhere. No help. Still no start. Heres the clues:

-Replaced starter and battery about a month ago.
-Have had the front fuse block out on the bench to clean up corrosion about 2 months ago.

-Checked every single fuse in the 3 panels with a multimeter, none popped
-Pulled pump housing to check for hose disconnection etc, found the ball point pen tip in the cannister. Bench tested the continuity of the ground and the pump operation (did not test pump pressure but seemed strong)
-replaced fuel filter

Still no start and now getting zero pressure at the rail.

DTC's

OBD2

P0171
P0420 CAT SYSTEM EFFINCY BELOW THRESHOLD
P0135 O XY SENSOR CIRCUIT BANK 1 SENSOR 2

MBENZ OEM

201C-001 MIX TOO RICH
201D-001 CAT CVRTR EFFECT INSUFFICIENT
202C-001 CAN SIGNAL INTERRUPTION
202C-004 AMBIENT TEMP IMPLAUSIBLE
2029-001 MIX AT RICH STOP
2038-008 SENSOR SIGNAL INERT FUEL SHTOFF IMPLAUSIBLE
P2600 CIRCUIT 87 UNDER V
P2601 CIRCUIT 87 OVER V
P2316 AC
P2314 AC
P2315 AC
P2560 TRANS SLIPPING
P2311 MESSAGES FROM ENGINE CTRL UNIT NOT AVAIL ON CAN
P2312 " "

Search queries have lead me to a possible malfunction with the inertia cutoff switch and the 2038 DTC could possibly support that Im guessing.

Any help?

 

There's either a clog, or your fuel pump is toast.

The fuel rail should have 55psi when primed, and the pressure sure hold for several minutes after the engine is turned off. You'll need to buy or rent the tool (pressure gauge) for testing the line. This thing screws onto the schrader valve.

How did a ballpoint pen tip end up there? If you are sure the pump is priming (should be a buzz of several seconds), there might be something physically clogging the pump.

To be honest it's probably easier to just swap out the pump. If you've had to replace the starter, the pump is probably near the end of its service life as well.

 

Thanks Slammer111,
Im guessing that the ball point pen tip was from propping open the fuel filler inlet flap. Why? Gas siphoning, or fuel additive, even crude diagnostic methods would require holding that spring loaded flap open. Ive had to prop it open with a screw driver to get gas into the tank from a complicated "safety can".

Any ideas on tracing or clearing a clog? Is it possible that a clog could occur downstream of the filter?
Are you familiar with this Inertia Cutoff Switch?

Thanks for your time!

 

Honestly if everything is out of the car, it might be easier to simply replace the pump assembly instead of trying to take everything apart. As mentioned, your pump is probably near the end of its service life.

Got a picture of the inlet flap? I don't remember seeing anything overly complicated when I replaced my pump. It was literally swapping 2 hoses over then dunking the thing back into the tank. Mind you I just did a direct swap (no troubleshooting), so I didn't fully disassemble the old one.

 

I don't see anything about the pressure.
Oriely will "loan" you a fuel pressure gauge if you pay for it, and return it in
2 days or just buy one at Harbor Freight for $20 and get some plumbers tape while you're at it to seal the connections.
Like slammer says anything below 55 psi but for me, it happened slowly, luckily.
Just kinda tapered off slowly, couldnt accelerate, got off the freeway and coasted at idle to my office. Seriously.
Pump is fairly easy to replace. I paid big bucks for a genuine MB one not sure if that was necessary,
Died at 200K
The other day I used my MBII ircarsoft unit went through all the menus for live data on my C230.
Wow so cool! I mean it tells you how much gas is in each tank!
If one tank is empty it could be sending unit on the other side of the tank.
My AC has quit and it told me I'm low on refrigerant and what the pressure was.
Had this for years and never knew it would do these things.
It also accurately pinpointed busted electronic shifter on our ML350.