I noticed my car was idling rough but brushed it off, then on the way home from work today I am driving in the fast lane and the car died, luckily i was able to pull over on the shoulder. I tried to restart and the engine cranks but wont start, just as im about to call AAA for a tow i gave it one more try and it started. Drove home, did my research and replaced the CPS. The next day on the way to work the exact same thing happened. Could this possibly be a fuel pump related issue? A friend of mine said sometimes the fuel line on these cars gets clogged. Any help would be greatly appreciated.

Thanks for the write up on the CPS install. Took my air vents off and finished the job in about 20 min.

 

Fuel pump or Throttle body....my .02

 

Get it scanned and look at TPS, MAP, Throttle actuator
The fuel pump triggers off of the CPS. A 2003 E55k might have dual fuel pump delivery system which requires a bit of diagnostic experience.
If it is a NA engine aim towards MAF.

Cheers, Gator

 

Its the Fuel pump relay on the right rear wheelhouse behind the airmatic tank in the trunk

 

Very possible. People forget this one a lot. Also, the aftermarket crank sensors are junk. Did you install a bosch one?

 

Check the fuel pump wire connectors under the rear seat-passenger side...see if they are melted.

 

Check the fuel pump relay socket...

I was dropping fuel pressure when the car was hot/ambient was hot, and it turned out my socket had melted, causing the relay to not make contact. Seems on early cars (03s) they had a single relay vs dual relay on the later cars. It seems that when the pumps age, they draw more current - causing the fuel pump socket to get hot/disform. Saw this on my 03 and on another 03 that is local to me.

 

Re:CPS fail. It happened to me out of the blue, no rough idle no symptoms factory part failed on 122k E55.

The exp let me know to continue to comb over commonly failing parts to get her up to snuff.

+1 for Electronic triage with experience points and multi-car issue trend.

Get a STAR if you are going to own one of these electronic nightmares my .02

 

CPS......first thing I changed on mine.....had 130k when I got her......10 minute job and cheap insurance....

 

Most of the E55's I've seen have had Fuel pump relays that look just like this. My suggesting is that EVERYONE change out the crunchy wire and really sockets.

 

would think a car that originally cost $85k or more would not have as many problems as they do.

 

I had similar experience as well. Got an aftermarket CPS, but that didn't do the job. I ended up buying an updated version from the dealer and never had that problem since.

 

Faulty logic. There is no correlation between cost of vehicle and reliability stats. In fact, the inverse from what you suggested is more than likely true: A cheap new japanese car is less likely to have failures than a six figure Rolls Royce/Bentley/Ferrari

Why? Mores expensive=more complexity

 

I just got a CPS from AH - P/N: 0031532828 - said "OEM" so hopefully its the right one?

Where can I get a new relay for the Fuel pump? Mine runs fine at 135K but I don't want a sudden failure.

 

I like proactive. Looks like I will be digging back there anyways fixing my automated trunk closer. So this is probably a good time to pull out, clean, inspect the relay's for wear.

Thanks for pics and reco bc I own a 2004 and thought I escaped the problem.

 

A link to part numbers for the socket and the replacement connectors.
https://mbworld.org/forums/mercedes-...ml#post6495500

 

Everyone should check this now.

I plan to get new fuel pump relay with the new pumps. But, do they sell a repair for the wiring? or should I just cut back the wire and replace the wire itself with new and solder with heatshrink tubing.

My wires going to the fuel pump seen kinda hard. Any recommendations?

 

Just follow the link in my post directly above yours. It can't get much simpler.

 

Thanks for those pics helped me get my e back on the road after sitting in my garage for a couple months

 

Thanks!

 

For folks reading this thread, note that AMGPilot's 2004 E55 has just one relay next to the reservoir in the trunk.

On my 2005 E55:
-where AMGPilot's car has the relay for the fuel pumps, my 2005 also has the relay for the air injection pump located under the left-front bumper.
-what would be the relay in the rear SAM for the non-AMG W211 fuel pump is the relay for the AMG W211 heat exchanger pump.
-what would be the relay in the front SAM for the non-AMG W211 air injection pump is the relay for the AMG W211 oil cooler fan located under the right-front bumper.

Note: your relay positions may be reversed from the ones in the attached photo. Just look for the melted relay and socket and that's your fuel pumps relay.

 

Where is that located on the MY 2005? I have the same.

 

She is screaming for me to tear it apart and take a look :-/ stop suspension refurb (tires going bye bye) back to electronics. I think I need to get used to the ping pong effect of this vehicle.

I wish I could just extract all bbirdwell's posts into .pdf. Where is a good site scraper when you need one lol..

Seriously thanks for all for the clarity you are offering... Look what SDS showed me today on the daily OCD scan:

https://www.amazon.com/clouddrive/sh...zXBVTHszn4NMY7

 

Right rear of trunk under the cover. No access port; you have to pull the cover out of the trunk.

 

The code is stored and not current. Clear it and recheck every week or so. If it comes back, time to check the harness under the rear seat. The harness and connectors under the metal covers will rub against the covers. Parts catalog's latest version has an adhesive cushion that sticks to the underside of the metal cover to prevent the harness from rubbing against the metal. When my fuel pumps exceeded 20 amps the harness under the cover was melted, brittle, and broken and just waiting to short against the metal cover.

FWIW, I *think* the 2004 E55 W211 air injection pump relay is located in the vicinity of the auxiliary battery. Sometime during the transition to the 2005 model year that relay was moved to the trunk.