E320 Starting problem

Had an intermittent starting problem on my 96 E320. It would crank but not start. I would let it sit and it would eventually start. Now, it cranks
but doesn't start at all. Noticed it on Friday, and it didn't start all weekend, or this morning (Monday). Since there could be multiple issues on why it won't start, does anyone know where to start? I would assume any of the fuel system parts from the pump, pressure regulator, injectors, and on down the line.
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I owned a '97 and had this happen: I installed a new battery and all was fine for about 9 months. Then one day I turned the key but didn't hear the fuel pump run for the usual one second prior to cranking the motor. I immediately knew the motor wouldn't start - and it didn't. But why no fuel pump?
Turned out that the new battery had leaked and acid not only corroded but disconnected the "christmas tree" of added-on wire connectors on the battery's positive terminal. The fuel pump was one of these corrosion disconnected wires yet the main connection was OK and therefore the engine still cranked!
So another new battery and soaking the corrosion damaged connectors in baking soda and water cleaned up the mess, a new 6 mm clamping bolt in a new "on bolt clamps all" arrangement lieu of the 8 mm original and it was fixed.
So take a look at the car's battery before attacking the engine.
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I agree with TG... change the battery first. Pick up a cheap one at Autozone... comes with 7 years warranty.
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"-->> T.G. Lambach <<--" <"T.G. Lambach at NoHamorSpamcomcast.net"> wrote in

I just changed the battery just 3 months ago, and didn't see any corrosion. But I'll check again. I do hear the fuel pump run before I try to start it.
Funny thing, after 3 days of not starting, I got a OBDII code reader from a friend that owns a Mercedes garage (no check engine light on, but just wanted to see if it picked up anything), and not codes came up. I figure I would try it again, and it fired up. My Mercedes mechanic friend thinks since there are no error codes, fuel pump works, could be the computer itself. He said he has seen them go up. The car has 200k on it.
Even though it fired up, I tried it about 10 more times. Half of those times it cranks for a few seconds, then gives me a clunking noise before it starts. (Also, I just replaced the alternator 2 weeks ago because of a previous issue).
Any other thoughts?
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it cranks for a few seconds, then gives me a clunking noise before it starts
Please elaborate on this "clunking noise". Is the motor sputtering and misfiring before it starts or is the noise mechanical?
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How about overload protection relay... this would cause non-start too. I'd go to part counter and see if any of those guys are helpful on this symptoms...
Another possibiltiy is the crank position sensor... I would bet on this over the OVP (above) as you are not getting an error code.
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