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Dallas, Texas
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8,223 Posts
Start Car at: 10 seconds
Car drops in RPMs: 35 seconds
Car Shutters hard until: 34-37 seconds
Car self throttles: 38 seconds
Car Shutters hard again: 1:07
Car drops in RPM's again: 1:22
Car recovers: 1:23
Car drops down again: 1:26
Car almost dies: 1:28
Car shoots up in RPM's again: 1:30
I press gas peddle slightly: 1:35
Won't rev over 1500RPMs: 1:38
Drops down, and I give it gas again at: 1:46
Car dies after 3rd time I touch the gas: 1:52
Restart car at: 1:58
Cycle continues
Twice during video oil level warning comes on. FSS reads -25700. What's up with that?

Check fuel pressure. It sounds like vehicle is running out of gas. Disconnect MAF then read codes. Verify that code reading works.
 

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98 ML320, 01 S500, 15 GL350
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587 Posts
Please explain/teach me why E lining is not a good practice...Thanks!

I may change my habit of filling the tank when almost empty.
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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4,714 Posts
I can't give you technical details but I understand that the dirt, usually residing at the bottom of the fuel tank, is more likely to find its way into the fuel filter clogging it and forcing the fuel pump to work harder and eventually packing up as a result.

Something like that anyway.:)
 

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Dallas, Texas
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8,223 Posts
Thanks Jim. I saw reserve light I just never heard that expression.
 

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2000 ML320, 2000 Audi TT Quattro, 1996 Acura NSX-T
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234 Posts
Discussion Starter #28
Where can I test for fuel pressure? I think I can check on the fuel rail, just don't know where to get a gauge for it. I also plan to get some more fuel in the vehicle- my sister has had it for the last 4-5 months, so I was unaware the fuel was low until I had it towed.

Whats odd is that if the fuel pressure is low- which makes sense, when it hits that 500RPM range it is able to jump up around 1500 RPMs, settle at 900, then drop to 500 and then jump up again.

I will disconnect the MAF and see if that generates a code.
 

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2000 ML320, 2000 Audi TT Quattro, 1996 Acura NSX-T
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234 Posts
Discussion Starter #29
I order an Actron Fuel Pressure Tester Kit (CP7818), from what I read online this one will work with our cars- others have used it. Once I get that i will test, I will in the meantime test unplugging the MAF and reading the generated codes.
 

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Dallas, Texas
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8,223 Posts
Where can I test for fuel pressure? I think I can check on the fuel rail, just don't know where to get a gauge for it. I also plan to get some more fuel in the vehicle- my sister has had it for the last 4-5 months, so I was unaware the fuel was low until I had it towed.

Whats odd is that if the fuel pressure is low- which makes sense, when it hits that 500RPM range it is able to jump up around 1500 RPMs, settle at 900, then drop to 500 and then jump up again.

I will disconnect the MAF and see if that generates a code.
ML has pressure test port same as most domestic vehicles. Located on right front of injector rail. Amazon.com: Actron CP7818 Fuel Pressure Tester Kit: Automotive

Put some fuel in the tank. Don't go more then half. If it turns out to be fuel pump you don't want to have tank full.
 

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2000 ML320, 2000 Audi TT Quattro, 1996 Acura NSX-T
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234 Posts
Discussion Starter #31
Well I got more fuel in the vehicle- its up past 1/2, around 3/4 of a tank. I charged up the battery and let the ignition is position 2 to let the fuel tank pressurize a few times.

The truck had a hard time starting the first few times. Once it got started, it was easy to restart when it would die. Same issues as before, here are a few things i tried and what was logged...

1.) I unplugged the MAF, it generated this code:
Address 01: 1 Fault Found:
P0110 - Intake Air Temp. Sensor (G42): Malfunction

When I plugged it back in and cleared the fault, it did not reappear.

2.) I logged the MAF (g/s). It varied between 6.5 to 9.5/10 when the car would idle, depending on the RPMs. When I was able to feather the throttle a bit I was seeing numbers above 10 to approx 17-18 g/s. Not sure what normal is.

3.) Again I logged the Short Term Trim and Long Term Trim %. The first time I logged it Short Term Trim % for both banks was 0% always. The Long Term Trim % for both banks stayed at 34.4% and never changed either.
The second time I logged it for longer the Long Term Trim stayed at 34.4% and never changed. The Short Term Trim almost always was 0%, but I saw 3.1% once on Bank 1, and 5.5 (once), 3.1 (twice) and 2.3 (once) on bank 2. This was over 51 logged responses... so bank 1 had 50 logged responses at 0% and one at 3.1%, bank 2 had 47 logged responses at 0% and 4 different numbers listed above.

I ordered a fuel pressure gauge, hopefully I will have that tomorrow. The remaining light on my on my dash is a low coolant light. Coolant seems to be non-existent in the tank, will fill tomorrow, just need to mix the coolant with distilled water tomorrow before filling. The truck has had a slow leak from the coolant system for some time, just haven't had time to track down the leak. I usually just fill up the tank once the light comes on, its a very slow leak, take about 3 months before it gets just below the min line, from the max line.

Any ways, that is the update... any additional thoughts?
 

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Dallas, Texas
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Vacuum leaks will cause same pegged LTFT. Take a look around.

.
 

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02 ML320 06 ML500
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I usually just fill up the tank once the light comes on, its a very slow leak, take about 3 months before it gets just below the min line, from the max line.
You better hope you're no burning it.
 

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2010 ML350 Bluetec
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519 Posts
I had a similar problem a few months ago however it turned out to be this:

The part is titled "Sender Unit" 003-153-27-28 $140

The interesting thing is that my GF was driving mine when the first symptoms occurred. ML's don't like women?
 

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2000 ML320, 2000 Audi TT Quattro, 1996 Acura NSX-T
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234 Posts
Discussion Starter #36
Just wanted to verify that this is the fuel inspection port on the engine- where I would connect the fuel pressure gauge?
 

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2000 ML320, 2000 Audi TT Quattro, 1996 Acura NSX-T
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234 Posts
Discussion Starter #37
I connected my fuel pressure gauge to the fuel rail line shown above, and measured the pressure coming out...

I confirmed it was a fuel line when a small amount of fuel left on the connector remained after removing when completed with the tests.

Upon connecting the gauge I saw the system has about 5-9psi of pressure. That level did not much much at all when I was cranking the car. Even when the car was running I did not seem really any increase. The gauge did move around a touch, but remained right around 9psi. When the car would switch to the lower idle the psi would drop slightly to around 5-7psi.

I know the pressure should have been much higher out of the gate. Wondering what I should check next? Are there sensors that would trigger the pressure to be so low? Is this indicative of a failing/failed fuel pump? A clogged fuel filter? or a sensor requesting the wrong fuel pressure?
 

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Dallas, Texas
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I connected my fuel pressure gauge to the fuel rail line shown above, and measured the pressure coming out...

I confirmed it was a fuel line when a small amount of fuel left on the connector remained after removing when completed with the tests.

Upon connecting the gauge I saw the system has about 5-9psi of pressure. That level did not much much at all when I was cranking the car. Even when the car was running I did not seem really any increase. The gauge did move around a touch, but remained right around 9psi. When the car would switch to the lower idle the psi would drop slightly to around 5-7psi.

I know the pressure should have been much higher out of the gate. Wondering what I should check next? Are there sensors that would trigger the pressure to be so low? Is this indicative of a failing/failed fuel pump? A clogged fuel filter? or a sensor requesting the wrong fuel pressure?
Normal fuel pressure is ~4bar, ~58psi. For explanation how fuel delivery works see:http://www.mercedestechstore.com/pdfs/508 Systems II/508 HO Part 07 Fuel supply (WJB) 04-01-01.pdf

Fuel pressure regulator is part of fuel filter. Even with it stuck open fuel pressure should get to ~20psi. Check delivery volume. Check fuel pump current consumption.

.
 

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1999 ML320 Elegance, BMW R1150RT, SAAB 9-3
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282 Posts
it is almost certainly your fuel pump. they do wear out (you have high milage) and operating the vehicle as you do with low fuel level on a regular basis has likely burnt out your pump (pump uses the fuel to cool itself - no fueling => no cooling).
get a new one and change the filter while you are at it.

that being said i see in the chart package there are two pressure regulators... one at the pump (chart 16-most likely keeps pressure in the system for fast restarts) and one on the fuel rail - item40 on chart4 and chart 17,18,19. i wonder if there is any way to test the pressure regulator at the fuel rail.. perhaps take it out and apply compressed air at different pressures and see if it flows?

edit; i guess if you do a volume check upstream of the rail mounted regulator and the test fails you can eliminate the rail mounted regulator as a cause of the low pressure.
 

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it is almost certainly your fuel pump. they do wear out (you have high milage) and operating the vehicle as you do with low fuel level on a regular basis has likely burnt out your pump (pump uses the fuel to cool itself - no fueling => no cooling).
get a new one and change the filter while you are at it.

that being said i see in the chart package there are two pressure regulators... one at the pump (chart 16-most likely keeps pressure in the system for fast restarts) and one on the fuel rail - item40 on chart4 and chart 17,18,19. i wonder if there is any way to test the pressure regulator at the fuel rail.. perhaps take it out and apply compressed air at different pressures and see if it flows?

edit; i guess if you do a volume check upstream of the rail mounted regulator and the test fails you can eliminate the rail mounted regulator as a cause of the low pressure.
That article shows fuel supply on many different engines controlled by ME-SFI. Not all of it applies to ML.

ML uses returnless rail with one and only pressure regulator in the filter.
 
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