CLK 320 Coupe Engine starting problem!..
06-09-2011, 06:25 PM
#1
Newbie
Thread Starter
Join Date: Jun 2011
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Mercedes-Benz CLK 320 Coupe
CLK 320 Coupe Engine starting problem!..
Hello folks
I live in Germany and have been having an interesting problem lately..
I have a 2001 registered Mercedes-Benz 320 Coupe (Benzine) at 230.000 Km.
On the fuel tank tap it says 95 octane but I always use 98 octane to have better performance. (I don't know it scientifically though..)
Last month I went to France for vacation. It's not as easy as here to find 98 octane there. So I filled 95 octane two times. 10-15 minutes after filling it second time (1200 km away from home) the engine stopped and didn't start again. I got my car repaired back in my mechanic in Germany. He said the problem was fuel pump and the filter. He changed them and it was working again. But with a slight different. The engine was starting immediately after the start-engine. But, after the repair it takes 3-5 seconds to start. When I try again to turn the key off and on again, it works immediately again. I try to analyze the problem to see "when" that happens I fail. Because in the mornings sometimes the engine starts with no delay, sometimes with delay. Let's say, after 5 to 90 minutes of rest, it always starts with delay. But as I said, I turn it off and on immediately at those times just to see if it happens or not, and the result: the engine starts perfectly soon again!!!
I know it sounds confusing, but I really want to know the cause of this problem if any of you guys had any experience like this. My mechanic said the diagnostic test results are OK he cannot find the cause..
I feel desperate these days..
I live in Germany and have been having an interesting problem lately..
I have a 2001 registered Mercedes-Benz 320 Coupe (Benzine) at 230.000 Km.
On the fuel tank tap it says 95 octane but I always use 98 octane to have better performance. (I don't know it scientifically though..)
Last month I went to France for vacation. It's not as easy as here to find 98 octane there. So I filled 95 octane two times. 10-15 minutes after filling it second time (1200 km away from home) the engine stopped and didn't start again. I got my car repaired back in my mechanic in Germany. He said the problem was fuel pump and the filter. He changed them and it was working again. But with a slight different. The engine was starting immediately after the start-engine. But, after the repair it takes 3-5 seconds to start. When I try again to turn the key off and on again, it works immediately again. I try to analyze the problem to see "when" that happens I fail. Because in the mornings sometimes the engine starts with no delay, sometimes with delay. Let's say, after 5 to 90 minutes of rest, it always starts with delay. But as I said, I turn it off and on immediately at those times just to see if it happens or not, and the result: the engine starts perfectly soon again!!!
I know it sounds confusing, but I really want to know the cause of this problem if any of you guys had any experience like this. My mechanic said the diagnostic test results are OK he cannot find the cause..
I feel desperate these days..
06-09-2011, 07:48 PM
#2
MBWorld Fanatic!
Greetings!
It may be the fuel pressure at the rail.
Try this and see if the problem stops. This is only a test, not a permanent solution. You may want to do this for the next week or so –
When a car is started, fuel is injected. To do this instantly, there must be sufficient pressure at the injector. The injectors receive their fuel from a fuel rail, which is fed by the pump. There is a specification for how much pressure is supposed to be at the rail when the car is turned off for an extended period of time. If that pressure is too low, the car will simply crank until pressure builds. When the key is in the second position, the fuel pump is on. By waiting three seconds, you are allowing pressure to build. To some degree, a pressure drop at the rail is expected. Your mechanic can plug a pressure sensor into the rail. The pressure sensor can be used to see how much pressure is bled off, and how long it takes to bleed down. I believe a STAR diagnostic box can do the same thing. A STAR box can also be used to see if your replacement fuel pump is building sufficient pressure within an allotted time (which would also be a pressure at the rail issue).
I hope that helps
It may be the fuel pressure at the rail.
Try this and see if the problem stops. This is only a test, not a permanent solution. You may want to do this for the next week or so –
- Insert the key and turn it to the second position.
- Wait three seconds.
- Then start the car.
When a car is started, fuel is injected. To do this instantly, there must be sufficient pressure at the injector. The injectors receive their fuel from a fuel rail, which is fed by the pump. There is a specification for how much pressure is supposed to be at the rail when the car is turned off for an extended period of time. If that pressure is too low, the car will simply crank until pressure builds. When the key is in the second position, the fuel pump is on. By waiting three seconds, you are allowing pressure to build. To some degree, a pressure drop at the rail is expected. Your mechanic can plug a pressure sensor into the rail. The pressure sensor can be used to see how much pressure is bled off, and how long it takes to bleed down. I believe a STAR diagnostic box can do the same thing. A STAR box can also be used to see if your replacement fuel pump is building sufficient pressure within an allotted time (which would also be a pressure at the rail issue).
I hope that helps
