ML 320 Starting Problem - PeachParts Mercedes-Benz Forum

#1 07-18-2004, 05:53 PM

My 99 ML320 has starting having problem starting. I turns over fine but does not start. I have read that two common failures are the fuel pump and security. I have replaced fuel pump and tried all of my keys when the problem occurs. Also, when using my key to unlock the drivers door, (not the remote) the alarm goes off. Can this be a sign of security failure? When it decides not to start, it typically last 24 hrs and then it is fine. Has anyone else had or heard of this problem? Also, I did system scan and no codes were present. I have also read that when replacing the pump, that the 3 fuel lines as well as filter should be replaced. I did not do that. Is the regulator part of the filter? Any help is appreciated!

Gilly · #2 07-18-2004, 08:50 PM

Hi

The problem with the alarm going off is normal, You're SUPPOSED to use the remote, not the blade, the blade is sort of "the last resort" to get in the truck, and yes, if it was locked (which *almost* has to be done with the remote) and you use the blade to open it, the alarm goes off, and as far as i know the only (or at least the best) way to stop the alarm is to insert the key into the ignition and turn it. (sorry about the bad run-on sentence)
As a matter of fact, the truck originally should have had a pair of black block-off plugs to keep the key from easily being used in the door lock cylinders, but people don't care, they take them off and toss them.
Yes, if the fuel filter was original, when replacing the pump you should have done the filter update (new long-style filter along with the updated lines).
Yes, the regulator is integral to the filter, and yes the regulators have been known to fail.
It's relatively easy, IF you are careful, to see if there is at least SOME fuel pressure by using the connection point on the fuel rail (press on end of schrader valve with small screwdriver or what have you, but don't get sprayed!).
It could still be a key problem, it can be pretty weird. Or maybe not the key but the DAS antenna for example. Best way to check for start authorization is to watch the small red LED dot above the foglight switch. When you turn the key to crank the engine, you should see a very short blink, about 500 m/sec blink, which indicates that DAS is authorizing the start.

Gilly

#3 07-18-2004, 09:32 PM

I have tested for pressure at the schrader (sp) valve and got some spray. Should there be a constant flow when turning over the engine? What could be the cause of the 24 hr delay? When it quits starting, it starts again the next day. Can this be related to the regulator not building pressure?

Also, I just went and looked for the light above the fog lamp switch...it was there so that should eliminate the key issue, correct?

Gilly · #4 07-18-2004, 09:52 PM

If you mean you're getting that short (500m/sec) blink, when you turn the key to crank, then I'd say that DAS is OK.
I didn't notice what you had said about the 24 hr thing. I don't think that's significant, just call it "intermittent" I guess.
I believe that YES you should have a good fuel supply when cranking. It should be a pretty strong spray, if you are uncertain then it's time to move on to a pressure gauge. Or do a supply test, but this isn't always a good indication of good pressure, just supply. I was hoping you'd say NO fuel came out the schrader valve, that's a little more useful info. If a little comes out, ehhhh, who knows for sure without a gauge. If it just dribbled out, probably on the right track though, should spurt out pretty healthily.

Gilly

#5 07-18-2004, 10:04 PM

Your input has been very helpful. I think I will replace the fuel filter tomorrow as well as the lines. I would be willing to bet that it will start tomorrow as the condition has never lasted more than 24 hrs.
As far as the fuel from the valve, at first it gave a light spray as it should as I relieve the pressure but does not build pressure again after that. The pump is new, relay and fuses have been checked so that leaves the filter/regulator. Can the regulator keep pressure from building as well as control pressure while running?

Gilly · #6 07-18-2004, 10:07 PM

Yes, it can cause a no-start condition.

#7 07-19-2004, 12:41 PM

OK Replaced fuel filter/regulator. Plenty of pressure and constant flow at schrader valve. Started once but now again, a no start.?????

Gilly · #8 07-19-2004, 02:39 PM

You can have problems like this immediately after replacing the filter because the filter has to get filled with fuel, try cranking it again.

Gilly

#9 07-20-2004, 09:40 PM

Ok No start again today, My local service tech cleared several trouble codes yesterday and ran OK for a while. Today, back at the shop and everyone is scratching their head. The codes are leaning toward key issues and/or intermitten starter relay not sending constant pulses to allow enging to start, therefore not telling the fuel pump to send fuel. Does this make sense?

Gilly · #10 07-21-2004, 04:18 AM

Kind of spotty info there. If they cleared several codes, what were they and what do they mean? Then, if it later refused to start, what codes came back???

Gilly

mbdoc · #11 07-21-2004, 08:12 AM

On the M112/113 engines that crank over but won't start at times, test the crank sensor. They are a very common failure on those engines. We replace at least 2-3 every day for that problem. about $100 for the part.
Won't register a fault code either!

#12 07-21-2004, 08:42 AM

What is the best way to test crank sensor?

mbdoc · #13 07-21-2004, 05:52 PM

If the engine WON'T start then the crank sensor shouldn't create any AC voltage durning starter operation.

sdanville · #14 08-17-2004, 04:35 PM

I have simular symptoms.
thanks
Steve

doc · #15 01-08-2005, 01:02 PM

I have a similar situation. 2001 ml 320 , engine turning over but not starting., MB Road service came and jump started the car and the car started. I was told the battery was weak. 2 days later same problem , no start but turning. MB service came and replaced battery they say was weak, however, car turning but not starting. Tech says fuel pump, sensor, bring to dealer HA HA. I have read these posts , am open to suggestions. which crank sensor goes bad , front or rear?
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