Have been chasing this issue for some time... any help or suggestion is much appreciated.

Car not starting. Narrowed to fuel pumps not running. Specifically, pump doesn't prime when ignition is turned on/cranking. On a very rare occasion after many many times turning ignition on and off the pump will audibly power and prime after which the car will start and run fine until it sits for some time after which it will not start again. No CEL, OBD codes or other warnings...I do not have access to Star Diag.

Due to fuel leak at cracked plastic connector on left pump (fuel smell issue!) and suspicion of issues with right pump I replaced both especially given mileage (75k). General performance was MUCH improved and fuel leak resolved. However, starting issue remained. I replaced fuel pump relay in rear... same results. I have checked voltage at 4 wire connector to right pump...no power when helper cranks engine. HOWEVER, when I disconnect the plug and manually apply 12v to the pump directly it immediately starts pumping and the car starts and runs perfectly. After idling for a period, re-checking the voltage at the connector yields 14v. Once voltage is measured I can re-connect connector and pumps power and car starts and runs normally...again, until car sits for some time and starting problem returns.

Only other suspicion/concern is that the shielding on the 4 wires into plug on right pump are split from being bent under metal pump cover. Suspect this happened after dealer finally replaced tank (fuel leak/smell!!!) It is only the shielding and the wires appear fine and obviously carry voltage after above procedure. I have taped each to assure no shorting.

Just FYI...I replaced CPS prior to this current issue due to starting problems and OBD code. That particular starting problem was resolved with new CPS.

Thanks! Again, any help is appreciated.
Doug

2005 W211 E55 wagon

 

are you sure you replaced the correct relay? the amg models are different than the non amg. the amg uses the non amg relay slot for the intercooler pump.

 

Thanks for the reply!!!

Yeah...you know that's a funny thing because I originally ordered #002-542-72-19 as everything I found said this was for the AMG. However, after recieving it and realizing it was not the correct one I re-ordered #002-542-11-19 which was the same as in the SAM in the rear of my car. Keeping in mind this is a wagon, some things are located differently than a sedan. The relay indicated in the attached picture is the one I replaced... does that look right to you?

 

thats for the ic pump on the amg models. ill see if i can send you a pic of the wagon version location in the morning. you might have 2. i know the 2006 has 1 relay per pump.

 

Thanks so much! Seriously appreciate the help!

Attached is the info I got off EPC StartekInfo based on my VIN... However, if you have something different, it wouldn't be the first time I have found a variance from this info .

 

Ok. Your original part number was correct. The location is very similar to the sedan version. Passenger side rear compartment behind the wheelhouse and by the airmatic reservoir tank. Sorry for the poor pictures. If your car was produced from june 05 and later it will have the k27/1 and a k27/2 like it's shows in epc

 

Rocman8 my friend, you are my HERO today!! Despite all other information I had found indicating the relay mentioned previously... YOU are 100% correct in all information provided.

I had looked previously at the right side of the car but didn't visually find any relays. It never really crossed my mind to remove the subwoofer...behind which as you indicated I found the culprit of my woes. Needless to say, I still had the new relay I had ordered previously. Just replaced it and BANG ZOOM... pumps primed and she fired right up! You ARE THE MAN. THANK YOU THANK YOU THANK for your time and willingness to help! I am truly grateful for your help. Please PM me with your address so that I can send you a thank you card and a gift card for you to buy yourself the adult beverage of your choice. I owe you !

Have a great day!

 

Awesome!!! Thank you for the offer but I am just happy to help a fellow member. Happy motoring

 

I love it when a plan comes together.

 

i know this is old post but can i have a picture with a relay location? Having exactly same issue. Pump isnt always priming the fuel. Once it does, no issues