W202 C180 Cold Starting Issue

mbzclk

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Hi Guys,

I have a good friend who is struggling with his fathers C180.

Whenever it’s cold the car turns but does not start. When it’s warmer it fires and runs perfectly.

A fresh battery has been installed.

A few days ago he tried to use a hairdryer to warm up the relay in the boot fuse box, when attempting to start the car the green and red RVM lights are flashing alternately. So it could be an immobiliser issue which we will remove from the circuit.

However, locking and unlocking cleared the immobiliser and the car started.

This morning I’m told it was the same with not starting but no immobiliser issue so maybe it was a red herring.

I’m thinking either the relay that has a fuse in it located in the boot.

The other point to note is the fuel level gauge does not work past 1/2 / 1/4 level. So thinking the level sensor but hopefully no issue.

But could be fuel pump? But when warm it’s perfect and drives spot on.

Either the coil packs and or leads - spark plugs to be replaced this weekend.

Or the black relay box in the engine bay.

The car has around 94,000 miles and they would rather keep then sell the car.

I’ve also been thinking it could be a cold air sensor or coolant / temp sensor?

Looking for any ideas / troubleshooting steps to resolve this and save the car!

Potentially looking to replace all the above components to rule them all out but wouldn’t be happy if the issue still persists.

Thinking of steps / parts to replace but don’t want to spend loads and still have issue present and unresolved.

Remove the additional dealer fit Mercedes alarm.

Replace Spark Plugs and Air filter

above two doing tomorrow

then possible items:

OVP in the boot fuse box.

Coil Pack & Leads

CPS?

MAF?

its the M111.920 engine.
 

mioba

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thats a great list of potential items which will cost you a bomb.
where are you based and get ti a mechanic who knows mercs.
 

LostKiwi

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For cold starts you can immediately rule out the MAF. Equally coil packs, leads and plugs.
Get the codes read /look at live data and stop guessing. It will be much cheaper in the long run.
 
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mbzclk

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Would the cold not cause a poor spark if bad leads / coil pack?

I’m thinking the OVP?

I may speak with AMF or someone else to get it solved just wondered if anyone else has suffered similar stuff or seen this. As stated. If it’s warm it’s perfect.
 
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mbzclk

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thats a great list of potential items which will cost you a bomb.
where are you based and get ti a mechanic who knows mercs.
Friend is based in East London.
 

LostKiwi

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'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Would the cold not cause a poor spark if bad leads / coil pack?

I’m thinking the OVP?

I may speak with AMF or someone else to get it solved just wondered if anyone else has suffered similar stuff or seen this. As stated. If it’s warm it’s perfect.
A rich mixture is comparatively easy to fire. When my r129 has ignition issues it runs badly when warm but starts perfectly.
 
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mbzclk

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Replaced CPS - no good.

using easy start causes it to start / fire. So a fuel issue of sorts
 
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