Newbie with W116 running issues

[Rockstarscars]

Hello everyone, sorry my first post is about a problem!

We recently became MC club members and have a W116 and a R107 500SL ( we’ve used as a daily and covered 40k miles in this one over the 10 years of ownership )

The 500SL is now a high days and holidays car, however we are using our W116 450SEL as a regular use / daily classic since buying it in August we have driven over 1300 miles in it. We are slowly improving it, we have had a number of isues, most of which have been resolved.

We have found the car difficult to start from cold or hot, and to that end, we have replaced the fuel filter, fuel pressure accumulator and all of the rubber pipes at that end of the car. This problem has now gone away, but we fear we have an ignition issue also which had confused our diagnosis, and in fact we had fuel AND ignition issues!

The ignition issues are getting worse. Previously The needs a minute or two to warm up, then car will run well for ever,

Lately, the needs a minute or two to warm up, then car will run well for 9-12 miles, then starts to splutter then after a few hundred yards cuts out altogether.


When the car is restarted, it will run for

A a few hundred yards before cutting out again

B more likely around 5-7 miles before cutting out again


If you allow 3-4 minutes ‘sitting time’ after cutting out then it will run for longer

Its almost like turning it off and on again resets/ discharges something / allows something to cool slightly

Unfortunately the problem is getting worse! so the component that was iffy, looks like its starting to finish!

Its got new plus / leads and the plugs are now correctly gapped.


I know theres what seems to be an electronic control box, a coil, a ballast resistor and something else that could now


Any ideas please?

Thanks

Kieron

 

[Blobcat]

Hello and welcome,

I've moved your thread into a technical section for you - you should update your profile with "your Mercedes" (rather than a password...)

 

[Rockstarscars]

Hello and welcome,

I've moved your thread into a technical section for you - you should update your profile with "your Mercedes" (rather than a password...)

amended now!! thanks!

 

[mattkh]

Please put up a close up of the ignition coil wires.
Is it really upside down as I can see in the picture.
Sometimes the coil can (excuse the pun) play up when warm.

 

[cagliere]

Hello everyone, sorry my first post is about a problem!

We recently became MC club members and have a W116 and a R107 500SL ( we’ve used as a daily and covered 40k miles in this one over the 10 years of ownership )

The 500SL is now a high days and holidays car, however we are using our W116 450SEL as a regular use / daily classic since buying it in August we have driven over 1300 miles in it. We are slowly improving it, we have had a number of isues, most of which have been resolved.

We have found the car difficult to start from cold or hot, and to that end, we have replaced the fuel filter, fuel pressure accumulator and all of the rubber pipes at that end of the car. This problem has now gone away, but we fear we have an ignition issue also which had confused our diagnosis, and in fact we had fuel AND ignition issues!

The ignition issues are getting worse. Previously The needs a minute or two to warm up, then car will run well for ever,

Lately, the needs a minute or two to warm up, then car will run well for 9-12 miles, then starts to splutter then after a few hundred yards cuts out altogether.


When the car is restarted, it will run for

A a few hundred yards before cutting out again

B more likely around 5-7 miles before cutting out again


If you allow 3-4 minutes ‘sitting time’ after cutting out then it will run for longer

Its almost like turning it off and on again resets/ discharges something / allows something to cool slightly

Unfortunately the problem is getting worse! so the component that was iffy, looks like its starting to finish!

Its got new plus / leads and the plugs are now correctly gapped.


I know theres what seems to be an electronic control box, a coil, a ballast resistor and something else that could now


Any ideas please?

Thanks

Kieron

Hi
You are just in the journey to solving all jetronic challenges. I would recommend you look at the the warm up regulator.
If you haven’t any specialists tools and are happy to tinker remove it and get it refurbed. You’re dealing with petrol pipes so be careful when removing the banjos.
Before you do that check the rubber vacuum hoses connected to the warm up regulator
Can’t go wrong with them remove them and make sure they aren’t perished.
Over the last 15 months I have replaced my pump accumulator cold start valve injectors refurbished the fuel distributor and refurbed the warm up regulator (three times)
Runs really well after resetting the CO!