What have I done or not done?

[ollieplimsoles]

Hi Folks,

Started out today to do what I presumed to be a simple job on my 1984 500SEC. When I bought this car in August 2006 it had been converted to run on unleaded fuel, ( I note from some other posts that this may have been unneccessary), by John Haynes. The conversion involved an in-line fuel catalyst - physically a metal cylinder containing materials to increase the rating of modern fuel - I believe a method used by the Soviet Union in WW2 to boost the quality of the aviation fuel available. I am sure many of you are familiar with this modification.

Anyhow, the fuel line from the catalytic cylinder to the in-let of the fuel injection sysytem under the air cleaner was made by way of braided flexible fuel hose - this had split and the vehicle was not safe to drive - so I had to replace it. I removed the old hose and replaced with the new - about 1m in length all told - and refixed with the original clips. However, on trying to start the car all I get is a repeated clicking noise while the battery, abs and interior lights just flick on and off in time with this noise. Why?

I disconnected the new fuel line and turned the engine over to see if any fuel was coming through the hose - but again just the loud clicking noise and no fuel emerging
from the hose. I guess that the two things may be unrelated and coincidently something else has happened while the car has been idle.

I have left the car with the hose disconnected and placed a tyre valve cap over the open end of the catalytic cylinder to await advice.

Other points that might help diagnosis are:

The car has not been driven for about 2 months due to a combination of lack of fixing time and weather.

There is fuel in the tank (not much).

Lights, blower, aerial and seat belt extenders are all operational.

When I turn the key all I get is repeated loud rapid clicking with flashing dashboard lights - not the sound of the starter motor trying to turn or the groan of a flat battery.

When I first removed the old hose fuel dripped in a short steady stream from the catalytic cylinder but not now.

I am mightily interested to hear what my learned fellow members feel is the problem.

Regards,

Mark S.

 

[Dieselman]

Sounds like the battery is so flat it wont engage the solenoid.

Fit the fuel hose and jump start the car, or charge the battery.

I thought the Mercedes engines had hardened valve seats anway, so didn't require the (broket) Tin catalyst anyway.
Having said that it's unlikely to harm anything so just leave it there.

 

[ollieplimsoles]

Thanks for that - the more I think about it the more I feel thats all it can be really.

Agree with you on the broket bit - most pre-war and all post-war MB engines have hardened separate valve seats so don't actually need any help to run on unleaded petrol.

As regards charging the battery - have you any experience of these Black & Decker charging packs or would I be best just buying a spare battery and jump the car from that?

Regards,

Mark S.

 

[grober]

Spend your money on a new battery. If its as flat as you say its probably beyond redemption. Get a heavy duty one at that.

 

[Dieselman]

Spend your money on a new battery. If its as flat as you say its probably beyond redemption. Get a heavy duty one at that.

I would disagree. For now I'd buy a battery charger and some jump leads.

 

[panason1c]

Spend your money on a new battery. If its as flat as you say its probably beyond redemption.

I agree, when a battery is allowed to go as flat as yours is and then left in that condition for a period of time it is unlikely to recover by charging.........Besides, if you buy a new battery .....you won't need a charger or jump leads..........on the other hand, if you buy a charger and jump leads you might still need a battery!

 

[ollieplimsoles]

Hi Folks,
Update as of today. Tried to jump start the car with the spare 55Ahr battery I have for the 190e and my jump leads - no joy

Well it did perform better than last week as a times it did sound like and engine trying to pitifully start not like last week when it sounded like a demented typewriter each turn of the key.

Also thought I'd try it again with just the current battery - but not a thing when I turn the key and even the seat belt extenders have a job extending!

I presume this verifies a (totally) flat battery? The only remedy seems to be a nice new 66Ahr battery as specified in the handbook?

I'm a little concerned that the 55Ahr battery didn't make a bigger impact though - should I be? I cranked the engine on and off over a period of 30 mins - all it did was sort of try to turn over ( the fan rotated this time

) then revert to 'typewriter syndrome'.

Regards,

Mark S.

 

[Dieselman]

You need a running car to belt some charge into the exisiting flat battery, or a completely charged replacement battery.

Is your spare battery absolutely brimmed on charge, if not it won't start a car with a flat battery still connected as the flat battery will flatten the charged one quickly.

 

[grober]

Charge up a good battery-the bigger the better! Buy some BRADEX EASI-START from Halfords. If that doesn't start it you will have to delve deeper.

 

[ollieplimsoles]

Update time. Thank you all for your advice - I can report a successful outcome

Replaced the dead battery with a nice new one. The replacement is a Numax 096 72Ahr and it has replaced a DERA 88Ahr item which looks a good battery and also fits much better than the Numax. Might try to revive this although my charger instructions say it is not to be used on batteries smaller than 20Ahr or greater than 60Ahr

However, still no go on turning the key but at least it sounded like a car trying to start this time - almost like there was fuel starvation.

To cut a long story short, I decided to fiddle with my relays... ooer missus . It worked! The large 'black one' (whatever it is?) at the back must have been jammed and the car is now running as good as ever.

Only downside is that I may have spent money on a battery I may not have needed at the start of this saga

However, some people are never satisfied.

Thanks again.... until next time.

Mark S.