500sec engine cutting out

[ollieplimsoles]

Hi Folks,

See ollieplimsoles post entitled 'What have I done or not done' for the background on this.

Car cut out to day. Lifted bonnet and twiddled the relays in my fusebox again - result - no problem car starts - away I go.

Car is still going but this may become a habit I fear. Obviously a faulty relay - but which one? Well not the 'silver' ones or the one with the red fuse. It seems to be the large black one in the top RH corner of the fuse box as you look from the front of the car. No distinguishing features or writing - except for a white dot. Any ideas as to what this one is?

Regards,

Mark S.

 

[Will]

Hi Mark,

Any pictures? It might help in working out what relay it is

Will

 

[television]

For a start I would buy some non drying switch cleaner and spray all of the relay bases and fuses, take them out spray and put back.

Thats the first move.

If the problem still continues,,, then start the car and leave it at idle, and by tapping all of the relays with a screw driver handle quite hard see if you can make they engine stop

 

[Mercedes cozy]

Possible faulty fuel relay. Might have a dry solder joint.

 

[skemball]

Ditto.

The proverbial dry joint on one of the relay contacts.

I had a vauxhall carlton years ago that would start fine and as the engine warmed up would cut out. AA man went straight to the fuel injection relay - a known fault apparently. I decided to opne up the old relay and it had a hairline crack on one of the connections on the PCB.

 

[television]

For testing the fuel pump relay you can bridge terminals 30-87 this will let the pump run continuously

 

[ollieplimsoles]

Thanks guys.

Here is an update on the problem. Happened again last night shortly after starting off. Car just conked out again. I lifted the bonnet and did my relay jiggling again - no joy this time

I tried this about three times but no response. Then after sitting for about 15mins - bang off she goes!

Now when this problem happens there is no response from under the bonnet ie not a sound from the starter motor - just a click of the key and..... nothing.

Lights, hazards, seat belt extenders are all operative but not a thing from the engine - might this hit the fuel pump relay theory on the head?

When she runs she runs faultlessly - just an aspect of the joys of classic/old car ownership I guess

Further suggestions?

Regards,

Mark S.Thanks guys.

 

[grober]

Broken/ corroded engine earthing strap?

 

[eurico]

Funky ignition switch?

 

[ollieplimsoles]

Hi Folks,

Update - car started first time last Sunday after sitting for a week. Drove for about 6 miles then returned to base - no problems. Very frustrating as I now don't have the confidence to take it for a longer run ... just in case it stalls again. I'll try it again this Sunday after another week and report back.

Regards,

Mark S.

 

[television]

If the car does not crank and cuts going dead.

Battery connection
earth strap
ignition switch.

Are there 2 faults then the list gets longer.

By putting a voltmeter onto the starter motor small terminal will you get the answer

 

[W210 Fan]

I had an SEC with very similar problems, dry solder joint on the fuel pump relay as Mr television has pointed out, next time she conks out/wont start turn the key to position 2 and try to listen for a slight whining from the rear of the car, its the fuel pumps priming the system, if you dont hear that, take the fuel pump relay out, crack the casing off and you will see a dry joint a mile off, 3 seconds with a soldering iron will solve this!! if your not happy with this you could bridge the connections, (they are all numbered on the connector under the engine bay,) with some thick wire, if she starts thats two tests that point to fuel pump relay as you have just bypassed it twice!! When I had my SEC I brought a service manual DVD for about £3 of fleebay which has lots of fault diagnosis charts and turned out to be invaluable with the older cars - as you say, part of the joy of ownership!!

 

[Dieselman]

Now when this problem happens there is no response from under the bonnet ie not a sound from the starter motor - just a click of the key and..... nothing.

Do you mean, nothing at all from the engine or does the starter solenoid make an attempt at engaging but fails to work fully?

If there is absolutely nothing check the ignition switch and cables leading to it.