I'm haveing a problem with my 07s550 won't start anyone figure out what is the reason for this and the solution

 

so what was the problem I'm having the same problem now

 

so what is the problem mines won't start I need to know why plz

 

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 !!!)

 

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 $$$.

 

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

 

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.

 

Replacing the relay does - in fact - correct a good portion of the inoperable fuel pumps in the W221...

 

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?

 

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).

 

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).

 

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).

 

The relay being bad could also be a sign that you need a new fuel pump.