Car turns over but won't start

Tiny
CORSTRAT
  • MEMBER
  • 1998 MERCEDES BENZ ML320
  • 195,000 MILES
A year ago, my grandson was playing with my key and broke off a half inch (only key I have). Surprisingly, the key still worked fine for the past year. A few weeks ago after several normal starts, all of sudden while the starter turned over as normal, it appeared it was getting no spark and would not start or even sputter.

I sprayed starter fluid in the mass air flow tube and it started and ran for a few seconds. I did the a few times and it started each time, so it is getting spark. I then checked the fuel pump and it is delivering gas. What it is not doing is getting any injector pulse.

My question is; can this lack of injector pulse be a problem that is being caused by a faulty key? I had been using this as a work truck and mechanically it was working fine, cosmetically it is in poor shape and not worth spending a lot of money on it. My dealer wants around $400 to give me a new programmed key which I would pay if I new for relative certain, the knew was the likely problem and not the computer. What I don't want to do is to buy a key and then find out it also needs a computer or other expensive item costing more than the truck is worth.

I can get a "valet" key from the dealer for about a third the cost of a new full function key, and since one of the doors can't lock anyway, I could live with just using the valet key and if it turns out the key is not the problem, not so much cash wasted. I have read on the Internet that as far as starting and running the truck the valet key works fine. Just doesn't give the locking features. Is this true?

Any help would be appreciated.

Sunday, July 28th, 2013 AT 8:08 AM

5 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
With the key in the run position is there any security or lock light on solid or flashing?Usually the valet keys I have see will work the ignition and doors but not the trunk or glove box if the ignition fit a glove box lock.A valet key still has to work the door so they can lock unlock your car when they park it.
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Sunday, July 28th, 2013 AT 8:54 AM
Tiny
CORSTRAT
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While my reading on the net tells me there should be such a light, I can't remember seeing any light flashing for at least several years and certainly not now.

I am aware the valet key should working on the doors, what I meant was that it would not work with a "button".
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Sunday, July 28th, 2013 AT 9:00 AM
Tiny
SATURNTECH9
  • MECHANIC
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I looked up the anti theft description on Mitchell ondemand which we use on here to answer questions on here. All it says is the horn goes off when doors hood etc are open with it set. Doesn't say if injectors are disabled. I know you said there is no injector pulse but with the key in the run position do you have powerto all the iinjectors? Also did you check for a injector pulse with a noid light or how?
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Sunday, July 28th, 2013 AT 10:03 AM
Tiny
CORSTRAT
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  • 3 POSTS
I had a neighbor who is a mech check it with a small light. He did tell me there was plenty of spark, the fuel pump was working (took the back seat out and checked it at the tank), but no injector pulse. He didn't have a lot of experience with MB, so he thought it was either the key or possibly the computer.
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Sunday, July 28th, 2013 AT 11:00 AM
Tiny
SATURNTECH9
  • MECHANIC
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So he hooked up a small light to both terminals of the injector connector and the light didn't flash while cranking?If so did he see what was missing the constant power with the key in the run position?Or theflashing ground?
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Sunday, July 28th, 2013 AT 5:31 PM

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