[ranz_5]

well this morning I went to start the ML started fine; ran for 10 seconds shut off, started back up same thing at least 3 times. I changed the CPS put a brand new one on. The red light that let you know it recognizes the key the light blinks so I know it recognizes the key.I have fuel pressure, I can feel the pump when it primes I can feel the pump when the car turns over, I can also feel when it’s running before it shuts off the pump still runs. I changed the filter put a brand new on same thing put the old one on, same thing. Only code I’m getting is a emission code. I was also told to disconnect the catalytic converters i have done that yet.
Does anyone have any pointers??

 

[2000 E 320 White Wagon]

Blocked Catalytic converters are quite common. All MLs in USA should have 4.

2 are in front just below exhaust manifold & have O2 Sensors fore & aft.

The rearmost 2 Cats are alongside & inside of frame rails. They don't have 02 sensors so they're called 'unmonitored'.

Much has been written here at length, if you just scroll down and view related threads you can find how to check them with a Non Contact Laser Thermometer.

Blocked rear cats are common as our rigs age. You can't tell cause no sensors to trigger an MIL.

Eventually you may get a MIL for a misfire or Front O2 as things back up.

But yes that could be the cause.

Harbor Freight has a nice Laser Thermometer for $30, its what I use.

At Idle speed & at 2,000 RPM when aimed at Cat temperature must be LOWER in Front and HIGHER in REAR by about 50 degrees +

If you find HIGHER in FRONT then they're blocked and causing trouble.
Replace with new aftermarket ones IF in a smog jurisdiction OR if not, removal & replace with straight pipe also works & will unblock things nicely.

Hope that helps.

David

 

[Witek_M]

Measuring temperature at this point will not provide any meaningful results. It takes ~1 minute for converter to reach temperature.

Checking exhaust back pressure with gauge is the only way.

 

[ranz_5]

Blocked Catalytic converters are quite common. All MLs in USA should have 4.

2 are in front just below exhaust manifold & have O2 Sensors fore & aft.

The rearmost 2 Cats are alongside & inside of frame rails. They don't have 02 sensors so they're called 'unmonitored'.

Much has been written here at length, if you just scroll down and view related threads you can find how to check them with a Non Contact Laser Thermometer.

Blocked rear cats are common as our rigs age. You can't tell cause no sensors to trigger an MIL.

Eventually you may get a MIL for a misfire or Front O2 as things back up.

But yes that could be the cause.

Harbor Freight has a nice Laser Thermometer for $30, its what I use.

At Idle speed & at 2,000 RPM when aimed at Cat temperature must be LOWER in Front and HIGHER in REAR by about 50 degrees +

If you find HIGHER in FRONT then they're blocked and causing trouble.
Replace with new aftermarket ones IF in a smog jurisdiction OR if not, removal & replace with straight pipe also works & will unblock things nicely.

Hope that helps.

David

Ok thank you for the info but checking the temperature wouldn’t be possible because the car only run for 10 secs.

 

[khomer2]

Clarify.
What emission (error) code.
Have you also check your fuel pressure at the rail?

 

[ranz_5]

Clarify.
What emission (error) code.
Have you also check your fuel pressure at the rail?

Im not home right now, I will have to look again but it was definitely a emission code and yes I’m getting great fuel pressure at the rails.

 

[khomer2]

Well, then it's witek's suggestion, or sawzall time.

 

[Witek_M]

Actually for testing purposes it would be enough to remove both front O2 sensors.

 

[ranz_5]

Actually for testing purposes it would be enough to remove both front O2 sensors.

Ok thanks, I will try this tomorrow!

 

[2000 E 320 White Wagon]

Ok thanks, I will try this tomorrow!

Uh duh, yeah sorry. What Witek said - I missed the the 'only runs for 10 seconds' part.

But if you pull those O2 sensors & she runs all the sudden, that will 'tell the story'.

It's be loud but still a proper test.

But also the Fuel rail test - should be very easy as theres a schrader style test port should be on pass side front fuel rail end.

HFT has a cheap fuel pressure gauge. A better way may be to get an O'reilly Auto or Auto Zone loaner. If Fuel pressure is low thats a clue.

You can also test it w/o gauge - just unscrew dust cap from the fuel rail schrader valve (like tire air valve) and with rag in hand / over valve to prevent fuel spray, push it in.

Does gasoline come out & how much pressure ? If key is on position 2 (dash lights on) it should squirt with high 50 psi pressure. If you get only a dribble, fuel pressure is low.

Hope that helps. Please report back and keep going until solved - it helps others in future.

Cheers - David in Texas

 

[ranz_5]

Uh duh, yeah sorry. What Witek said - I missed the the 'only runs for 10 seconds' part.

But if you pull those O2 sensors & she runs all the sudden, that will 'tell the story'.

It's be loud but still a proper test.

But also the Fuel rail test - should be very easy as theres a schrader style test port should be on pass side front fuel rail end.

HFT has a cheap fuel pressure gauge. A better way may be to get an O'reilly Auto or Auto Zone loaner. If Fuel pressure is low thats a clue.

You can also test it w/o gauge - just unscrew dust cap from the fuel rail schrader valve (like tire air valve) and with rag in hand / over valve to prevent fuel spray, push it in.

Does gasoline come out & how much pressure ? If key is on position 2 (dash lights on) it should squirt with high 50 psi pressure. If you get only a dribble, fuel pressure is low.

Hope that helps. Please report back and keep going until solved - it helps others in future.

Cheers - David in Texas

Yes the pressure gets up too 50 taking the o2 off will be next

 

[ou1954]

I'm just a casual observer but there is a 1999 ML320 in the house so I do watch with interest. I find it difficult to believe that to significant exhaust flow devices would suddenly and instantly become blocked. I find it hard to believe that a bad or failing O2 sensor would cause an engine to stop within 10 seconds. Rough running, probably, but stop . . . Really?

My current 1999 ML 320 problem is finding two screws that are missing from under the driver foot area. That area has never been touched by the dealer or myself but they are gone. My current task is to find the right thread to help me identify those screws which seem to hold up a trim panel.

In the meantime I wish success to the OP on this thread, both for him and potentially for me some time in the future.

 

[ranz_5]

I'm just a casual observer but there is a 1999 ML320 in the house so I do watch with interest. I find it difficult to believe that to significant exhaust flow devices would suddenly and instantly become blocked. I find it hard to believe that a bad or failing O2 sensor would cause an engine to stop within 10 seconds. Rough running, probably, but stop . . . Really?

My current 1999 ML 320 problem is finding two screws that are missing from under the driver foot area. That area has never been touched by the dealer or myself but they are gone. My current task is to find the right thread to help me identify those screws which seem to hold up a trim panel.

In the meantime I wish success to the OP on this thread, both for him and potentially for me some time in the future.

just don’t let your battery sit dead for over a month lol.

 

[ou1954]

Not a chance. I did indeed have a car in storage at Bekins for a year while I worked overseas. They put it on blocks and put the battery on float charge. All fine when I got back.

 

[2000 E 320 White Wagon]

.....My current 1999 ML 320 problem is finding two screws that are missing from under the driver foot area. That area has never been touched by the dealer or myself but they are gone. My current task is to find the right thread to help me identify those screws which seem to hold up a trim panel.
....

Do you mean the underdash panel that is above the drivers feet & pedals. The one that has the OBD2 port built into it & heat duct too ?

Mine had 2 fasteners of one type & 2 of the other.

I had mine off for some months and lost 2 of the 4 fasteners.
Was able to scrounge a spare from my son in laws ML.

I can post pics if this is what you mean.

Thanks David