C-Class (W202) 1995-2000: C 200 CDI, C 220 CDI, C 270 CDI, C 180, C 200 K,C 230 K, C 220, C230, C 280

99 W202 C240 Won't start

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Old Apr 19, 2009 | 02:48 AM
  #1  
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1999 C240
Unhappy 99 W202 C240 Won't start

Help! About 2 weeks, the car wouldn't start. Out the blue one morning engine turns over no problems, but not a hint of running.
Checked all the fuses, and found the rear fuses near the battery and the location of the fuel pump relay - and searched the web.
Found the crank position sensor discussions and found the sensor on the flywheel housing and wiggled the wires. Also disconnected the battery for 10 minutes and then reconnected - and hey presto - engine starts.

Now tonight the very same thing. Only problem being that I don't know how I fixed it last time!

The engine has been running fine with no issues - so I'm hesitant to blame the crank sensor - no rough idle or stalling at all.

Could the fuel pump relay at the rear fuse box be at fault?

Any ideas?

Update - there is definately a spark - I pulled a plug lead and it sparked away against the cylinder head. Could I change the fuel pump relay for another one - or are relays voltage/load specific?

Thanks

John

Last edited by mintyish; Apr 19, 2009 at 03:32 AM. Reason: Update
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Old Apr 19, 2009 | 05:13 AM
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1999 C240
Success.

I swapped the fuel pump and fuel return pump relays and it started - just like normal.

Off to work in the morning - and I can get a new relay at lunchtime. Only question is will I have to go full throttle all the way to use all the fuel, so the engine doesn't flood without a fuel return pump

John
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Old Apr 20, 2009 | 04:41 AM
  #3  
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1999 C240
Disaster!

Went out to the car this morning and it was back to turning over and not a spark of life - so possibly not the fuel pump relay after all.

I called the dealer today and they couldn't think of anything either - other that plugging it in and seeing what comes up on the diagnostics.

Looks like I'll have to get it towed tomorrow as tonight, I couldn't get any closer to getting it started...

John
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Old Apr 21, 2009 | 08:12 PM
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From: Franklin Mass
1999 C280 Sport
My C280 did the same things but it was the CPS. Worth while changing it as they don't last forever. Take it out and look at the end, could be dirty.
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