How to Disable Fuel Pump?
Thread Starter
Senior Member
Joined: Nov 2017
Posts: 269
Likes: 27
From: Bay Area
2013 P31 C63 Sedan
How to Disable Fuel Pump?
Hey everyone, need some help figuring out how to disable the fuel pump. Reason being, after oil changes I like to turn the engine over for at least 5-10 seconds to build some oil pressure before starting it. Unfortunately when I bought my C63 the fuse list in the engine bay was missing. I've tried searching and found the fuel pump is connected to multiple different fuses (4,6,19,23,27,42). With M156's being so picky about oil, anyone know how to shut off the fuel pump and let the engine turn over?
MBWorld Fanatic!
Joined: Jun 2008
Posts: 8,078
Likes: 2,867
From: Los Angeles
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
This map of fuses and relays is great. https://www.autogenius.info/mercedes...e-box-diagram/
I’d try the 40A fuse hanging off the positive battery terminal in the plastic holder with only one other fuse. (my car had a 25A in there which blew and killed power to the fuel pump, either way it’s the smaller of the two fuses you want to pull)
I’d try the 40A fuse hanging off the positive battery terminal in the plastic holder with only one other fuse. (my car had a 25A in there which blew and killed power to the fuel pump, either way it’s the smaller of the two fuses you want to pull)
MBWorld Fanatic!
Joined: Mar 2010
Posts: 5,894
Likes: 324
From: CH = Land of mountains, cheese, chocolate and watches
12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
This map of fuses and relays is great. https://www.autogenius.info/mercedes...e-box-diagram/
I’d try the 40A fuse hanging off the positive battery terminal in the plastic holder with only one other fuse. (my car had a 25A in there which blew and killed power to the fuel pump, either way it’s the smaller of the two fuses you want to pull)
I’d try the 40A fuse hanging off the positive battery terminal in the plastic holder with only one other fuse. (my car had a 25A in there which blew and killed power to the fuel pump, either way it’s the smaller of the two fuses you want to pull)
Thread Starter
Senior Member
Joined: Nov 2017
Posts: 269
Likes: 27
From: Bay Area
2013 P31 C63 Sedan
This map of fuses and relays is great. https://www.autogenius.info/mercedes...e-box-diagram/
I’d try the 40A fuse hanging off the positive battery terminal in the plastic holder with only one other fuse. (my car had a 25A in there which blew and killed power to the fuel pump, either way it’s the smaller of the two fuses you want to pull)
I’d try the 40A fuse hanging off the positive battery terminal in the plastic holder with only one other fuse. (my car had a 25A in there which blew and killed power to the fuel pump, either way it’s the smaller of the two fuses you want to pull)
FCPEuro somehow managed to ship me the oil change kit without the filter so now that sets back my plans for this weekend
Thread Starter
Senior Member
Joined: Nov 2017
Posts: 269
Likes: 27
From: Bay Area
2013 P31 C63 Sedan
Just wanted to update this thread. Did the oil change today and pulled the fuse BLKROKT mentioned. To confirm, it was a 25A fuse next to the positive terminal 
Worked beautifully. Couple things to note: after pulling the fuse, start the car up again to burn the excess fuel in the lines before draining the oil. Also, after cranking the car for (3) 10 second intervals you will get a check engine light for a P06xx code (can't remember the exact code). Just grab your OBDII scanner and clear the code, all is well. Massive thank you again to BLKROKT!
Worked beautifully. Couple things to note: after pulling the fuse, start the car up again to burn the excess fuel in the lines before draining the oil. Also, after cranking the car for (3) 10 second intervals you will get a check engine light for a P06xx code (can't remember the exact code). Just grab your OBDII scanner and clear the code, all is well. Massive thank you again to BLKROKT!
MBWorld Fanatic!
Joined: Aug 2011
Posts: 5,351
Likes: 1,677
From: Kitchener, ON
2010 C63 AMG
Those starter motor only revolutions will be just as dry until partial pressure builds for oil to flow. Even then, is it enough pressure to get all the bits in the head you're worried about?
Thread Starter
Senior Member
Joined: Nov 2017
Posts: 269
Likes: 27
From: Bay Area
2013 P31 C63 Sedan
Yes the initial revolutions will be dry, but no where near as fast as when the engine running. Cranked the engine over in three 10 second intervals then put the fuse back. Fired up the car and the engine was as quiet as ever. Can't answer whether or not it got all the bits oiled in the heads, but I can say it sure got most of it. I got tired of doing oil changes and hearing the M156 tick loudly for the first 5-10 seconds at 1000-1500 RPMs waiting for oil to reach the heads.
Last edited by curt.r; Aug 12, 2020 at 12:06 PM.
Trending Topics
MBWorld Fanatic!
Joined: Aug 2011
Posts: 5,351
Likes: 1,677
From: Kitchener, ON
2010 C63 AMG
Yes the initial revolutions will be dry, but no where near as fast as when the engine running. Cranked the engine over in three 10 second intervals then put the fuse back. Fired up the car and the engine was as quiet as ever. Can't answer whether or not it got all the bits oiled in the heads, but I can say it sure got most of it. I got tired of doing oil changes and hearing the M156 tick loudly for the first 5-10 seconds at 1000-1500 RPMs waiting for oil to reach the heads.
It's absolutely no different than letting your car sit for a few days.
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
MBWorld Fanatic!
Joined: Jun 2008
Posts: 8,078
Likes: 2,867
From: Los Angeles
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Exactly ^
I can understand for a turbocharged car wanting to get oil flowing through the bearings first, but for our engines think it’s totally unnecessary.
I can understand for a turbocharged car wanting to get oil flowing through the bearings first, but for our engines think it’s totally unnecessary.
Thread Starter
Senior Member
Joined: Nov 2017
Posts: 269
Likes: 27
From: Bay Area
2013 P31 C63 Sedan
Yeah, it's definitely overkill. I do it with all my other vehicles to fill the oil filter after installing to avoid a dry start. Probably doesn't make that much of a difference on these engines but it's 2 seconds to unplug the fuse and not hear pronounced lifter tick on startup after an oil change. Thanks for the input, all is appreciated.
Last edited by curt.r; Aug 12, 2020 at 03:37 PM.
MBWorld Fanatic!
Joined: Aug 2011
Posts: 5,351
Likes: 1,677
From: Kitchener, ON
2010 C63 AMG
Letting the engine spin with the starter ~200RPM may be doing more harm than good though. I doubt the oil pressure will be high enough to lubricate what needs to be lubricated.
Engine builders usually use an external auxiliary oil pump to build pressure.
Engine builders usually use an external auxiliary oil pump to build pressure.
