Hi All,

10 days ago my 99 ML320 with 89k miles would just not start up. It would crank with all the juice but not turn/start. I tried it numerous time and it did start 3 time in all from about 50+ tries but when it did start, it started within a second of cranking w/o any hesitation. Spent the whole 10 days on various online forums trying to figure things out.

Here is the scenario:
I do not get any 'start error' when I crank and the security led does blink once when I turn the ignition. I have tried both keys and no success. So I think we can eliminate the DAS malfunction. Also all the relays and fuses have been checked.

I bought a new fuel pump, filter and fuel lines. Changed the fuel pump, and tried cranking. It fired up within a second. My brother and I did the high fives thinking we had fixed the problem. We let it run for a couple of minutes, the syetms primed up and the RPM dropped to the regular idle rmp (~ 700-800). We switched the car off, to put the filter in since I had bought it along with the new fuel lines. Unfortunately we tried to crank it up, and now the same thing. It cranks but there is no turn/start!!. Since the whole truck is open, I can tell you that there is no power coming to the new FP.

The only 2 things left is a faulty CPS (Crankshaft positioning Sensor) or a bad ECM My question is, does a faulty CPS also prevent power going to the FP?

Also how do I short the FP relay to make sure power is going to the FP

Any help will be greatly appreciated

Sy

The fuel pump has a relay..front fuse box..that relay must receive signal from fuel computer (ME-SFI) that you are trying to start the engine..NO crank input & no fuel pump relay signal...

ON German relays you by-pass by connecting circuit 30 to 87...marked on relay.

Crank sensor is the MOST common failure on the M112/113 engines.

There is a ML forum...

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I have 135,000 oem miles on my ml. Should I replace the crank sensor as a precaution, to avoid a no-start problem? I'm also having the following done at this time: tranny eplug; pinion seal; rear shocks; power steering reservoir; fuel filter (last changed at 80,000 miles when the updated pump was installed); front brakes & rotors, since I'm going to give the ml to my daughter for use at grad school out of town. Thanks.

__________________
87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)

Thanks for the reply

I apologise for posting in incorrect forum. Shall I post it in the ML forum?
I shorted the relay and the Fp whirls up. However even changing the relay doesn't work? only if I short it. But even after shorting the relay the engine cranks but does not turn

regards

as mentioned, yer best bet is the crank position sensor.
cheap and not hard to replace. no codes for this but it
causes all kinds of problems.

george

An update on my probelm: Had the car fixed. It was actually the Ac condensor fans motor that had shorted out.