S-Class (W140) 1991-1999: 300 SD, S 350TD, 300 SE 2.8, S280, 300 SE 3.2, 300 SEL 3.2, S320, S320L, 400 SE, S420, 400 SEL, S420L, 500 SE, S500, 500 SEL, S500L, 600 SE, S600, 600 SEL, S600L, 500 SEC, 600 SEC

cranking but no start. no 12v at fuel pump

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Feb 9, 2013 | 09:12 PM
  #1  
w140forlife's Avatar
Thread Starter
Newbie
 
Joined: Feb 2013
Posts: 3
Likes: 0
s320 s420 s500
cranking but no start. no 12v at fuel pump

hello,
recently my cousins (7-94) s320 its been having some starting issues.
it started by running fine until one morning the car wouldn't start. it would keep crank and crank but would not run . after a few days staying in the driveway would start without a problem would run and drive fine for a day or so and all in a sudden the problem persists again cranking but wont turn over . started by checking fuel pressure but there is none in the fuel rail changed the fuel pump (30a) fuse in the trunk and fuel pump relay and still no difference, tried to test the voltage at the fuel pump plug wire and there is 0 volts with the key in position 2. what would the problem be a bad ecu unit , a bad cps or ignition module.?? and also which one is the LH and ecu in this box. thanks all
Attached Thumbnails cranking but no start. no 12v at fuel pump-wp_001383.jpg  
Reply
Old Feb 10, 2013 | 11:57 AM
  #2  
oldsinner111's Avatar
MBWorld Fanatic!
 
Joined: Jun 2010
Posts: 1,246
Likes: 52
From: tennessee
s320
ignition switch maybe

My case no pump or fire.I had been having trouble with my ignition switch now it quit .Mine has 170,000 miles,so it made it that many key ons.
Might be your problem.I don't know if pump has a relay,there are several in the trunk
Reply
Old Feb 10, 2013 | 01:30 PM
  #3  
w140forlife's Avatar
Thread Starter
Newbie
 
Joined: Feb 2013
Posts: 3
Likes: 0
s320 s420 s500
Originally Posted by oldsinner111
My case no pump or fire.I had been having trouble with my ignition switch now it quit .Mine has 170,000 miles,so it made it that many key ons.
Might be your problem.I don't know if pump has a relay,there are several in the trunk
thanks for your reply. yes there is a 30a amp fuse for the fuel pump in the fuse box in the trunk and also next to that fuse box there is the fuel pump relay as well. changed those both and still no difference no fuel pressure at all in the fuel rail. car cranks and cranks but wont start. if the key is worn out does that have to do anything with the fuel system by preventing the car to no start but only crank?
anyone else experienced this on their s320's?
Reply
Old Feb 10, 2013 | 02:26 PM
  #4  
oldsinner111's Avatar
MBWorld Fanatic!
 
Joined: Jun 2010
Posts: 1,246
Likes: 52
From: tennessee
s320
key

It might but I believe in might be the switch,there plastic
Reply
Old Jun 19, 2014 | 08:51 AM
  #5  
CLKTHEO's Avatar
Newbie
 
Joined: Jun 2014
Posts: 13
Likes: 0
1998 CLK320 Cabriolet
Did you resolve the problem?

Originally Posted by w140forlife
thanks for your reply. yes there is a 30a amp fuse for the fuel pump in the fuse box in the trunk and also next to that fuse box there is the fuel pump relay as well. changed those both and still no difference no fuel pressure at all in the fuel rail. car cranks and cranks but wont start. if the key is worn out does that have to do anything with the fuel system by preventing the car to no start but only crank?
anyone else experienced this on their s320's?

Hi im having a similar problem did you resolve it? could you pass on any info that could help me please?

Thanks for your time.
Reply
Old Mar 5, 2015 | 09:03 PM
  #6  
Delamoya's Avatar
Junior Member
 
Joined: Jan 2015
Posts: 27
Likes: 2
S500 w140
Try replacing the fuel pump? My guess would be the pumps have failed.
Reply
Old Mar 9, 2015 | 12:55 PM
  #7  
burgca's Avatar
Super Member
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jan 2014
Posts: 535
Likes: 44
From: Pottstown, PA
'97 S500 Coupe, 2016 AMG S63 Coupe, 2007 Audi Q7
If your issue is with a CLK320 M112 engine have you replaced the CPS?
Reply
Old Mar 10, 2015 | 08:42 AM
  #8  
oldsinner111's Avatar
MBWorld Fanatic!
 
Joined: Jun 2010
Posts: 1,246
Likes: 52
From: tennessee
s320
have you checked fuel pump relay,next to rear fuses,they can go bad.
Reply
MB World Stories

The Best of Mercedes & AMG

story-0

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-1

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-2

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-3

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-4

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-5

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-6

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-7

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-8

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
story-9

10 Most Reliable Mercedes-Benz Models You Can Buy Used

 Verdad Gallardo

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 04:51 PM.

story-0
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-1
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-2
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-3
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-4
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-5
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-6
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-7
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-8
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE