2007 S550 won't start!
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Joined: Oct 2014
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2007 s550 mercedes
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Joined: Aug 2014
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S500
I have a 2007 S550 that will turn over and start and then immediately shut down or just whine and never catch. After trying to start the car 10 - 20 times it will start and run just fine with no warning or check engine lights. I have seen multiple people in this forum with the same problem but I don't see any solution posted??? I brought the car to the dealership where they kept it for a full week and said that they couldn't find any codes nor could they get the car to not start!!!!! WTF , I think they are playing games with me because when I got the car back home, the next morning it did it again. " Does anyone know what the problem is"?
re rereading it properly, it sounds like fuel pressure....
if it starts and runs for up to say 20 seconds its using up residual fuel pressure in the rail... the idea should be the pump comes in and the pressure (depends on each car what causes it to run) is there from the get go. Sounds like on yours its not getting signal reliably.
my ramblings when I thought you kept trying to start and stop with too sort a duration... Like manoeuvring the car round the drive to get another one out...
this may be part of the problem....
Any car with a CAT should not be started and turned off again straight away. As a min hold revs at 2k for at least 40 to 60 seconds before shutting it down. In fact its good practice to run a car for a min of 10 miles every time you start it... (its why Taxi's do 500,000 miles and others need an engine at 60,000)
There is a huge risk a lot of unburnt very rich cold start fuel confuses the sensors in engine management that control fuelling / help look after the CAT. Believe it or not you can easily flood a fuel injected CAT car (my wife 's Pug 306 2ltr 16v and her Golf 1.6 16V BOTH did it.... doing exactly what I told her not to do see first paragraph !!!)
Last edited by BOTUS; Oct 3, 2014 at 11:50 AM.
Newbie
Joined: Nov 2014
Posts: 1
Likes: 1
From: SD, CA
07 S550
Hello all,
I recently encountered this issue... Similiar symptons as most already stated. This thread helped in isolating it to the fuel pump (for whatever reason everything check good when they performed code checks also) but the pressure was found to be extremely low. We got a new one but that didn't fix the issue.
Actual fix on my end was having the fuel pump relay replaced ($32.00 part). I don't know anything about cars but I love my mechanic. Hopes this helps save someone $$$.
I recently encountered this issue... Similiar symptons as most already stated. This thread helped in isolating it to the fuel pump (for whatever reason everything check good when they performed code checks also) but the pressure was found to be extremely low. We got a new one but that didn't fix the issue.
Actual fix on my end was having the fuel pump relay replaced ($32.00 part). I don't know anything about cars but I love my mechanic. Hopes this helps save someone $$$.
Member
Joined: Sep 2014
Posts: 140
Likes: 5
From: nevada
08 clk63, 06 E55, 05 c55, 14 ml350, 98 pathfinder. Have owned cl55, s55, cls55, c230, cl500, cls500
There is a service bulletin to check voltage drop for the control side of fuel pump relay from the engine control module. If there is no voltage drop engine control module is faulty. I've done a few of these for crank no start
Newbie
Joined: Feb 2016
Posts: 1
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2007 Mercedes S550
Fuel pump relay will not solve the problem
99% on 2007 S550 cranked but wont start. You will need to replace ME (Engine control module) $1100-$2400 part depends on VIN. replacing relay will not do it.
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Newbie
Joined: Aug 2020
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W221 S550 4Matic (AMG/Designo)
Has anyone pinpointed the root of this problem.
I have a 2007 S550 and same problem persists intermittently. I have replaced the fuel pump relay, filter, and the pump as well as the crankshaft sensor to no avail. There are no codes that would relate to this in my ECM. I noticed that the ambient temperature jacked up to 132 degrees once and as I started cranking it began to drop. Once I unplugged the ECM and replugged it and the car started right up.
Any suggestions?
I have a 2007 S550 and same problem persists intermittently. I have replaced the fuel pump relay, filter, and the pump as well as the crankshaft sensor to no avail. There are no codes that would relate to this in my ECM. I noticed that the ambient temperature jacked up to 132 degrees once and as I started cranking it began to drop. Once I unplugged the ECM and replugged it and the car started right up.
Any suggestions?
Newbie
Joined: Sep 2021
Posts: 3
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S550
Thank you for this post. My 2007 S550 was turning over but would take 5-10 tries before it would kick right over. Seemed to be lack of fuel. I swapped the relay (S) in the rear armrest console with relay R as they are the same to see if it was a bad relay and it fired right up. I will be getting a new relay to replace R as that one was faulty. I almost thought it would be the check valve in the fuel pump (not servicable must replace entire pump assembly).
Newbie
Joined: Sep 2021
Posts: 3
Likes: 0
S550
Thank you for this post. My 2007 S550 was turning over but would take 5-10 tries before it would kick right over. Seemed to be lack of fuel. I swapped the relay (S) in the rear armrest console with relay R as they are the same to see if it was a bad relay and it fired right up. I will be getting a new relay to replace R as that one was faulty. I almost thought it would be the check valve in the fuel pump (not servicable must replace entire pump assembly).
Newbie
Joined: Sep 2021
Posts: 3
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S550
EPA Fuel Pump Relay (S) behind rear armrest
Super Member
Joined: Feb 2009
Posts: 713
Likes: 214
From: Brooklyn, NY
2007 S550 4Matic 2013 S550 Base
Thank you for this post. My 2007 S550 was turning over but would take 5-10 tries before it would kick right over. Seemed to be lack of fuel. I swapped the relay (S) in the rear armrest console with relay R as they are the same to see if it was a bad relay and it fired right up. I will be getting a new relay to replace R as that one was faulty. I almost thought it would be the check valve in the fuel pump (not servicable must replace entire pump assembly).
