98 ML320 No Start - No Fuel - PeachParts Mercedes-Benz Forum

mplafleur · #1 06-08-2004, 01:16 AM

As title suggests, I have a no start. It first occurred yesterday and corrected itself.

Won't start with either key.
No fuel pressure in rail.
No voltage at fuel pump fuse.
Relay swapped with other relays.

I pulled the relay and shorted out the relay contacts in the distribution block. Confirmed voltage now at fuse. Still no start.

Wait........

Just went out to truck. Verified that there was still no fuel pressure in the rail with the relay bypassed. Does the ECU disable injection as well as the pump if it can't verify the key?

Wait.....

I verified that while the fuel pump gets no power with key on, it does provide power during crank. Relay and fuse are working. Fuel pump is not.

I hear this is a known proplem? Can I get this fixed gratis even if out of warranty. (If I have a civil dealership nearby)

Gilly · #2 06-08-2004, 08:37 AM

Make sure you are seeing the flash in the red LED on the dash when cranking indicating DAS release.
I believe that you should have fuel pressure even if DAS isn't released, it's the actual "injection" which is not functional if DAS isn't released, pressure should be there. Backing up this observation is the fact that no pressure is present at the rail. If injection isn't authorized, the pressure would have no place to go and you should have had at least an initial pressure remaining, possibly the truck would have ran for 15 or 20 seconds on the residual pressure. Did it? Also when cranking watch the odometer field for a "start error" message.
I think you're on the right track with the pump. Has it ever been replaced? Also has the fuel filter been updated to the long filter yet? The fuel filter itself is the fuel pressure regulator BTW, and can also cause a no-start condition.
Make sure you watch for that split-second "flash" of the red LED though, because it could still be a DAS problem (antenna ring around ignition lock and/or amp) even though the keys could be fine.
If your profile is correct ang you have 110K on this truck, I would doubt any help would exist, unless you are like "solid gold" to the dealer because if it's the pump, yes it's common, but they'll think "he got 110K out of the pump (assuming it's original), he has nothing to complain about". If the pump was replaced in the last year it's under spare part warranty.
Gilly

PHAEDRUS242 · #3 06-08-2004, 10:38 AM

In the case that the pump is not the culprit, we do replace tons of AAM's in these trucks for phantom no start conditions. Something to keep in mind during the diagnositic process.

G-Benz · #4 06-08-2004, 12:13 PM

Lost my pump last weekend while stranded in a lonely country road at dusk...1000 miles away from home!

MB Roadside Assistance had me play with the antenna ring as well to see if it was a DAS problem, but no go.

Towed 80 miles to the nearest MB dealership and they confirmed 0 psi fuel pressure.

Parts for the upgraded fuel filter were on backorder, so I had to settle for just getting the pump replaced (or take another extended week of vacation).

Pulled codes and found the MAS was bad as well (read -40 ambient at startup)...no wonder it's been performing like a pig lately.

Mine had under 57K and there was no warranty or goodwill replacement for the pump. Couple that with the MAS replacement, and I was out $1100!

mplafleur · #5 06-08-2004, 12:26 PM

I can't remember if I saw the red LED flash. I did look for a "start error" and saw none.

My wife couldn't start the truck after she got home from work, so I can't say if it didn't try to run. I do know that when I had the no-start on Sunday that it would idle for about 1 second or so before stalling out. After a number of tries, it wouldn't catch at all. Forum member whunter was with me at the time and we determined that we had no pressure in the rail.

I had a VMI run before I bought the truck and I don't recall that the pump was replaced so I'd have to say it is original. (and so is the filter) I don't hold much hope that any dealer is going to do anything for me.

Where is the fuel filter on this beast? I'd like to look at that tonight and verify that input and output. I have a parts locater CD and found the pump, component M3/3 but can't find the filter.

Does anybody know the component designation for the filter?

Gilly · #6 06-08-2004, 12:39 PM

The pump is in the tank, it's integrated into the fuel level sensor. You need to remove the left half of the rear seat, then lift up the carpet and there is a round metal panel that is bonded to the floor that needs to be removed to access the top of the tank.

The fuel filter I don't believe has a component designation.

Gilly

mplafleur · #7 06-08-2004, 01:12 PM

Gilly,

Where's the filter/regulator?

mplafleur · #8 06-08-2004, 01:35 PM

I found it through the search function!

Fuel Filter Replacement

Jack up left rear wheel, remove wheel and inner plastic fender.
Filter is on top of chassis just forward of brakes and held by a stainless clamp.
Caution - There are 2 filter sizes. Due to the small space on the ML, the smaller one is correct.
Place large container below chassis to catch gas when the lines are removed.
There are 4 lines. The main one from the tank(right) is a dual release fitting.
The back and left fittings are single press release.
The front(small) fitting is a stainless snap-off one.
Install new filter in reverse order.

Any trick with these fittings?

altheg · #9 06-08-2004, 01:54 PM

Along these lines, my 98 ML is running poorly. I bought a new MAF through a online Mercedes parts dealer, installed it, but does not run better.
Took it to a independent MB specialist and asked him to look at fuel pressure. He said it was low (about 35 psi) and recommended replacing fuel filter/regulator. This helped but pressure is sill in the 40's. He said spec is about 53 psi.
Do you think I should replace fuel pump ?
Would ML run poorly with 44 psi fuel pressure ?

mplafleur · #10 06-08-2004, 04:10 PM

If the fuel pressure is supposed to be 53 psi then indeed being in the 40's would cause a poorly running engine. The injectors would not deliver the correct amount of fuel. On a typical car, a fuel pump will deliver about 100 psi to the regulator. Not sure about the MB.

Can someone confirm the correct fuel pressure?

mplafleur · #11 06-08-2004, 11:30 PM

I have removed the filter/regulator ($76 for that?!) and cranked the truck. No fuel spewing from the line so I guess it's down to the pump.

sdanville · #12 09-07-2004, 11:35 AM

Thats in my list of fixes to figure out my occational starting problem.
I read it can be...

Fuel filter
Fuel Pump
Crank Shaft balancer
MAF
AAM
Fly wheel speed sensor

mplafleur · #13 09-07-2004, 12:44 PM

Yes. It is a combo fuel pump and fuel level sender. I had to replace the in-line fuel filter and a few of the lines too. I removed the rear seat and pulled up the carpet. There is a round access plate you can pry up (may have to heat it with a hair drier first) to get at the fuel sender. Everything is pretty self-explanetory. Although it isn't easy to remove the clips that hold the fuel lines together.

The hardest part was replacing the filter. You have to remove the tire (left rear) and the plastic liner to expose the filter which is strapped to the frame.

Truck runs fine now.

360glass · #14 01-03-2005, 12:38 PM

OK...now, I am having a very difficult time removing the liner. Any tips? I have removed the six bolts holding the thing in place but can't seem to figure out how to remove it....Thanks in advance for your help....

Ric,
Ann Arbor
2000 ML320, 118k

sdanville · #15 01-03-2005, 02:20 PM

what is the liner >?

if you mean the lid over the fuel pump--
i used a flat head screw driver and pryed it like a paint can lid. you can use a nail bar -crow bar.-