I'm a first time poster here but I've used the site many times to fix problems.

My car just decided not to start this afternoon. It was running fine when I went to the store.I came out of the store and it cranks over fine but won't start. I checked with a timing light and I'm getting spark at the plugs. I located the OVP relay and checked the fuse and it was fine.
Should I replace the relay anyhow ?
I'm at a loss on what to do now .

Thanks in advance .
Al

Possibly MAS control unit is at fault. Can you hear the split second buzz from the fuel pump package when you turn the key to the "run" position?

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Regards,
Aaron

Replace the OVP.

Replace the Fuel pump relay.

Check the crankcase sensor.

Check to see if the updated OVP has been installed and/or replace with a known good unit. Fuse alone is no indication that OVP is working.

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Zafar
94 E320 58000 Miles

If you are Positive about spark, then it is not OVP .
I would do a fuel pressure test at fuel rail port...
if none, then check pump relay/power as Zaf has posted.

Fuel Pump, go under the Car and tap firmly on the fuel pump to see if it comes to life, replace it if it does, don't forget a filter also

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Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles

After having the car sit overnight, I went out and cranked it first thing and it started up but immediatly the revs dropped off and it died. It started twice more for a few seconds (1 or 2) but I couldn't keep it running.
I bought a new fuel pump relay and replaced it but there is no change at all. It turns over just fine but it will not catch and start running. I can't hear anything from the fuel pump,but its dark outside so I'll wait till tomorrow and see if smacking the pump helps anything.
Zarf posted that I should check the crankcase sensor. Where is it and what should I be looking for ?
Also the MB parts guy said it can't be the ovp if the radio operates. Does this sound kinda fishy to you ? What are some indications that I can easily check to eliminate the ovp. According to some pictures posted on other threads mine has been replaced sometime in the past.

Thanks for the replies.

Al

I replaced the fuel pump relay and still the car wont start. I removed the cover from the pumps and tried to check voltage at the pumps with the key on and the engine off. there was no voltage present. I had my son turn the ignition key to the run position while i had my hand on the pumps and they ran for one or two seconds and shut off. He then tried to start the car and the pumps did not run at all.
Should I have 12 volts at the pumps when KOEO ?
Should the pumps start up again when turning over the engine?
Should I try to run power to the pumps stragiht from the battery and see if I can start anyway ?
What else should I try ? I am at a loss for ideas now .

Thanks in advance

Al.

Could it be your anti-theft kicking in ?

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2007 C 230 Sport.

Give the OVP a couple of taps w/screwdriver handle and try it ..
The Fuel pump only run for 1 sec when starting.

I tried tapping the ovp a few times and no success on starting.
should I go ahead and replace it anyway ?
I checked the spark using an inductive timing light and arthur siad if i have spark it won't be the ovp.

What should I check with the alarm system ? when I unlock the doors the red led goes out and the starter does turn over so I thought that since the starter worked the alarm system was functioning ok

I'm almost ready to call the dealer and have them tow it away .

Al.

I'm not sure if reading this will help you at all.
http://www.peachparts.com/shopforum/showthread.php?t=111316&highlight=anti-theft
Have you got/tried another key ?
I believe the anti-theft only kill fuel, not spark.

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2007 C 230 Sport.

ATA only kills start on 124 chassis... nothing to do with key system

Okay Boss.
I'll just shut up & go to bed now.

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2007 C 230 Sport.

Have you checked for a clogged fuel filter(s), like jerrywagner suggested earlier? If it checks ok, then you can manually power up the fuel pumps and try to start it. You could either do as you suggested earlier or you could remove the fuel pump relay and jump pins 30 and 87 on the socket. Just be sure to use an inline 40 amp fuse either route you decide to take.

Check the L5. It's behind the head from memory on the m104 with efi.
Probably just dirty. They were quite reliable on that motor.

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Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi