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2001 ML55 AMG, 2005 E55 AMG, 2000 ML55 AMG, 2000 C230 Kompressor
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39 Posts
Discussion Starter #1
Hi guys,

I've been trying to spare a pretty clean bodied and non-rusty 2000 ML55 w/ 174,000 miles that I picked up for $900. Obviously cheap price but it was REALLY behind on maintenance. For some reason though, I still have this problem where if the car sits for an extended period of time and you go to start it up it cranks for approximately 5-7 seconds before it starts......almost indicative of a fuel delivery issue. Anyhow, to keep a long story short here's what I've done to it that I thought would improve/solve this issue:

Replaced the fuel pump, fuel filter and fuel lines this past weekend with the following branded parts and part numbers:
Delphi Fuel Pump (OEM I believe): 1634703594 (FG1162)
Mahle Fuel Filter (OEM I believe): 1634770201
Vaico Fuel Line to Fuel Pump: 1634702864
Febi Bilstein Fuel Line to Fuel Pump: 163470296464
Febi Bilstein Return Line: 1634703764

Also too, I've deleted the secondary cats and replaced the primary cats with 2 new Magnaflow 54956 high flow cats and replaced the upstream O2 sensors with Bosch OEM 0005408117

What I am missing here? Should I be looking at the fuel system regeneration valve? Or fuel injectors leaking? Or elsewhere?
 

Premium Member
2000 ML55 sold馃槩 2013 ML500,馃榿 2015 C250 estate wagon, 1927 Dodge 4 sedan, 1929 Dodge
Joined
4,559 Posts
Hi guys,

I've been trying to spare a pretty clean bodied and non-rusty 2000 ML55 w/ 174,000 miles that I picked up for $900. Obviously cheap price but it was REALLY behind on maintenance. For some reason though, I still have this problem where if the car sits for an extended period of time and you go to start it up it cranks for approximately 5-7 seconds before it starts......almost indicative of a fuel delivery issue. Anyhow, to keep a long story short here's what I've done to it that I thought would improve/solve this issue:

Replaced the fuel pump, fuel filter and fuel lines this past weekend with the following branded parts and part numbers:
Delphi Fuel Pump (OEM I believe): 1634703594 (FG1162)
Mahle Fuel Filter (OEM I believe): 1634770201
Vaico Fuel Line to Fuel Pump: 1634702864
Febi Bilstein Fuel Line to Fuel Pump: 163470296464
Febi Bilstein Return Line: 1634703764

Also too, I've deleted the secondary cats and replaced the primary cats with 2 new Magnaflow 54956 high flow cats and replaced the upstream O2 sensors with Bosch OEM 0005408117

What I am missing here? Should I be looking at the fuel system regeneration valve? Or fuel injectors leaking? Or elsewhere?
Well I think you鈥檝e done everything that could of caused that. I would now try turning the key to pos#2 and leave it there for 10 seconds before you start it. If it starts straight away that would indicate low fuel pressure before start. Unlikely since you鈥檝e changed the filter. But you never know.
Then you need to check your fuel pressure with a gauge and see what it says.
 

Registered
2001 ML55 AMG, 2005 E55 AMG, 2000 ML55 AMG, 2000 C230 Kompressor
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39 Posts
Discussion Starter #3
Well I think you鈥檝e done everything that could of caused that. I would now try turning the key to pos#2 and leave it there for 10 seconds before you start it. If it starts straight away that would indicate low fuel pressure before start. Unlikely since you鈥檝e changed the filter. But you never know.
Then you need to check your fuel pressure with a gauge and see what it says.
Thanks Matt - so I did try that and I am getting mixed results. For example, I went out this morning and put the key to position 2 waited for 7-10 seconds and then cranked it and it started with much less stumbling and such but still not a strong start like my 01 has on cold starts.

I gave it a few hours and came back to repeat the same thing and the car cranked for 4-6 seconds before starting.

Odd....

I'll give the pressure test a go tomorrow morning. If I get results outside of where they should be though - where to next?
 

Premium Member
2000 ML55 sold馃槩 2013 ML500,馃榿 2015 C250 estate wagon, 1927 Dodge 4 sedan, 1929 Dodge
Joined
4,559 Posts
Thanks Matt - so I did try that and I am getting mixed results. For example, I went out this morning and put the key to position 2 waited for 7-10 seconds and then cranked it and it started with much less stumbling and such but still not a strong start like my 01 has on cold starts.

I gave it a few hours and came back to repeat the same thing and the car cranked for 4-6 seconds before starting.

Odd....

I'll give the pressure test a go tomorrow morning. If I get results outside of where they should be though - where to next?
With engine running at idle you should get around 55-60 psi and 30 minutes after shutdown it should be around 30-36 psi.
 

Registered
2001 ML55 AMG, 2005 E55 AMG, 2000 ML55 AMG, 2000 C230 Kompressor
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39 Posts
Discussion Starter #5
With engine running at idle you should get around 55-60 psi and 30 minutes after shutdown it should be around 30-36 psi.
Gave the fuel pressure test a go..............first time doing this so I'm a bit of a newbie so I have a few questions:

1. when the key is in position 2 shouldn't the fuel pressure gauge show some sort of reading?
-for some reason I wasn't getting a reading until the car was actually running

2. is there a Mercedes specific fuel pressure gauge that is recommended? I'm a bit skeptical of the results I got which was basically a consistent 2.5 bar (approximately 35 PSI). I wasn't really looking to dig around for a Mercedes specific fuel pressure gauge so I went down to Harbor Freight and purchased their master fuel injection test kit. Can't tell if the HF gauge is just way off the mark here. Any recommendations?
 

Premium Member
2000 ML55 sold馃槩 2013 ML500,馃榿 2015 C250 estate wagon, 1927 Dodge 4 sedan, 1929 Dodge
Joined
4,559 Posts
Sounds like a bad fuel pressure regulator in the new filter.
The fuel pump runs for a few second with the key in position 2 so you should have good pressure at start up.
What was the fuel pressure 30 minutes after shutdown.
Any normal fuel pressure gauge should work just fine.
 

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2001 ML55 AMG, 2005 E55 AMG, 2000 ML55 AMG, 2000 C230 Kompressor
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39 Posts
Discussion Starter #7
Sounds like a bad fuel pressure regulator in the new filter.
The fuel pump runs for a few second with the key in position 2 so you should have good pressure at start up.
What was the fuel pressure 30 minutes after shutdown.
Any normal fuel pressure gauge should work just fine.
Good point.....maybe I order one directly from the dealer and see if that makes a difference.

So after 30 or so minutes fuel pressure stayed basically consistent at 32 PSI. So if the gauge is accurate than not really indicative of a fuel injector leak.

So you're saying that I should be getting a reading on the gauge when the key goes to position 2?
 

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'73 450 SLC / '74 450 SL / '01 ML55
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465 Posts
You said poor maintenance, and report 174k. Mine had excellent maintenance yet at 140k I had a similar issue. I replaced the CPS and that problem went away. In my case it had nothing to do with poor fuel supply. It was an inexpensive part, a PITA to install but well worth the effort.
Not say'n it will cure your ills but you are gonna be doing it anyway
 

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2001 ML55 AMG, 2005 E55 AMG, 2000 ML55 AMG, 2000 C230 Kompressor
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39 Posts
Discussion Starter #9
You said poor maintenance, and report 174k. Mine had excellent maintenance yet at 140k I had a similar issue. I replaced the CPS and that problem went away. In my case it had nothing to do with poor fuel supply. It was an inexpensive part, a PITA to install but well worth the effort.
Not say'n it will cure your ills but you are gonna be doing it anyway
Troglodyte - thanks for the response. Can you elaborate some more on the symptoms you had?
 

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2000 ML320 LHD
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663 Posts
OP symptoms have nothing to do with CPS. I'm with Matt on this. Check that the fuel lines to the filter & pump are well secured without leaks/ escapes.
 

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'73 450 SLC / '74 450 SL / '01 ML55
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465 Posts
Troglodyte - thanks for the response. Can you elaborate some more on the symptoms you had?
Granted, the ML sitting a long time in this house would average 14 hours. My problem was always the first start of the day. Normal operation was turn the key and it starts "Instantly", then it started to want to just crank no start. It got to a point (and I did not put up with it long) that it would not fire instantly. Once it started I never had a problem the rest of that day, never got stranded no problem stop, go, run hard, run soft, perfect engine operation.
I never crank on any thing for longer than 6 seconds, but I will retry every 10 or 20 seconds (as I run all of the what can it be's in my head) boat, car, mower what ever. Did that when I was young and dumb wires get hot and things burn out.
Googled the problem by year, make and model. Read several "opinions" and watched at least 3 videos, the one common denominator was CPS and I did not find the CPS on the 5 page maintenance list I got from the MB dealer on this car.
For the record I now own the recommended Autel Scanner, I did not at that time. I cleared all codes the first thing, the car had not seen the dealer in 2 years. (I put up with the fuel level problem, it's not affecting the day to day running)

As I said "this may not be your problem" but it is an inexpensive part and they "are" known to fail

I agree Matt knows his shit, and I was not trying to diminish his knowledge and or input
 

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2001 ML55 AMG, 2005 E55 AMG, 2000 ML55 AMG, 2000 C230 Kompressor
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39 Posts
Discussion Starter #12
OP symptoms have nothing to do with CPS. I'm with Matt on this. Check that the fuel lines to the filter & pump are well secured without leaks/ escapes.
Have the car basically apart again and have checked the fuel lines to the filter and pump.......all are secured without leaks or anything of that sort.

I'm leaning towards my issue being maybe caused by leaky fuel injector(s)............anyone had this issue here before?
 
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