500sec, Help! Only one spark when cranking

[ammercman]

After replacing the fuel pump relay,crank sensor,ignition control module,spark plugs & leads I only get one strong spark when cranking then nothing from plugs.
checked the idle control valve that's working okay, I'm stumped as to where to go from here. Any idea's guys?

 

[neilrr]

After replacing the fuel pump relay,crank sensor,ignition control module,spark plugs & leads

How much have you spent on this guessing game?

Take it to a good MB indy who can pinpoint the problem.

 

[grober]

On the HT side of things---still to be checked/replaced---rotor arm---distributor cap--and coil. Best to find a garage with an old fashioned oscilloscope based engine analyser and someone who knows how to use it as has been said already .

 

[jaymanek]

the cheapest way of sorting this will be to buy a running spares car.. they normally go for around £500... swap bits until you find whats causing your issue...

I have had to do the same many times...

Then either sell the donor car or scrap it and sell some of the valuable bits... you can even make some cash this way.

 

[ammercman]

Thanks for the ideas guy's much appreciated.
Call it luck or fate whatever you want! today a gent walked into my place of work who is also a member of this fine forum! After explaining my predicament to him he has agreed if need be to swap some parts over from his 500 in a bid to resolve the issue, bloody angel, god bless him!!
If we can find a solution I will post it. Thanks again & watch this space.

 

[ammercman]

Problems solved!!
After six long weeks of stress my coupe is finally back on the road. After replacing the cps she ran up first time then died & would not run again just cranked all day long, after some much needed fuel & a lot of cranking with fuel pump relay disengaged to clear flooding. The plugs were sparking once strong then nothing, cps signal was okay to ignition coil & the dizzy seemed to function okay so after advice from a trusted & excellent diagnostic technician colleague I took a punt on the ignition coil persuading myself the constant cranking had lead to it's downfall! Decided genuine part was the only option as Eurocarparts didn't do them. After placing the said item on V.o.r with Mercedes of Leicester, I was left feeling the red mist the following day when the part arrived at the local dealer damaged, not the dealer's fault I might add you could see the Coils King lead socket was missing a number of pieces which were not in the box so had to have been damaged before supply. The Parts manager true to word delivered the part out to me within 24 working hours, nice one mate! Just got her cleaned & she's looking a beast again.
I feel justified in not using my local indy as all they could advise was it had to be a fuel issue,WRONG!! the only parts that were not really required was the ign control mod & fuel pump relay, the I.C.G proved difficult & expensive to get hold of, eventually acquired through ebay motors from the states at a fraction of the price of what part specialists were providing in the U.K. I don't mind having that spare from what I have learned I may need it one day. So all in all not to expensive & a lot learned.
All part of the trials & tribulations of owning a young timer!
Thanks for all the advice all.

 

[ammercman]

Your welcome Pontoneer, any problems and their solutions shared makes life easier for the next man!