broken down !

[johntom]

Hi
i went on a shopping trip to York today in my 1990 SL300, a journey of 40 miles each way. No problems on the way, however on setting off home, the car drove perfectly for about 4 miles then died!
I was travelling at about 50 mph when the rev counter seemed to dip a couple of times then the engine stopped, leaving me stranded on the side of the carridgeway ! The car had nearly 1/2 a tank of fuel left and all the electrics were working.
I called for the RAC who turned up and towed the car off the motorway slip road. He then connected his battery charging leads (due to being towed with the lights, heater and hazards on), put on the spark tester and turned the key - the car started (and got me home without further incident)?
Now i am worried about using the car incase it happens again, any ideas what could have happened or which parts may be to blame?
many thanks

 

[roofless]

not a car i know well. best for now try the search.put in 300 sl & you will find some good tips

 

[television]

I am going to say CPS though not common on this car it can go, the other thing is a crack in the PCB of the fuel pump relay

http://www.detali.ru/cat/oem_mb2.as...GM=717.434&CT=M&cat=505&SID=15&SGR=090&SGN=05

 

[johntom]

thanks for your reply
cps being crank position sensor, but what is the pcb and where is the fuel pump relay?
many thanks

 

[JEZ.S320L]

thanks for your reply
cps being crank position sensor, but what is the pcb and where is the fuel pump relay?
many thanks

I would go with Malcolms first suggestion - the CPS. Your symptoms match exactly what happened to my sons MB and one of my Jags!! PCB = Printed Circuit Board. Sounds expensive to me! The CPS is the cheapest option, fortunately.

 

[television]

thanks for your reply
cps being crank position sensor, but what is the pcb and where is the fuel pump relay?
many thanks

The car is based on 124 electrics,,not sure if it has a fuel pump relay, it is on these things where fitted that one track goes open circuit on the PCB. and easy fix if the car stopped through lack of fuel. I am not sure that it has one as there were so many changes in the early year without looking it up

 

[johntom]

broken down

Hi
i tried starting the car earlier today, it fired started for about 1 second then stopped and won't restart. I have tried a spark tested between the ht lead and plug - it does seem to be sparking?
I can hear a sucking kind of sound coming from the unit (fuel pump?)above the battery in the boot ?
thanks

 

[television]

If you have a spark then not the CPS and this must be fuel related,,I will turn on the other computer shortly and check

 

[Smudge]

Should you need any fuel related items for this car, give me a shout.I broke one last year and have plenty of spare bits!

 

[television]

Fueling on these cars depends upon the system used.

Cars with an fuel pump relay, remove the relay and bridge terminals contacts 7 and 8, this will let the fuel pump run all of the time, if the car runs then the relay will be open circuit on a PCB track.

Cars actually built in 1990 and uses KE injection control, then to make the fuel pump run all of the time, bridge contacts 11 and 20 on the KE control unit.

The above will of coarse test the fuel pumps, and they should be running when the above is done

 

[malcolm E53 AMG]

Hi,
Had a similar problem with my 300TE which I believe shared the same IL6 engine. Car would start and then cut out after travelling 2/3 miles. To cut a long story short the problem turned out to be the distributor cap and rotor arm, which after 70K were past their best, and condensation forming in the cap led to arcing and the engine cutting out. What was really puzzling at the time was that the engine would start again after standing for twenty minutes or so, probably enough time for the residual heat in the engine to dry the unit out.

Hope this helps

Malcolm

 

[johntom]

broken down

Hi
how do i know if the car has the KE injection system or not (it was registered on 07/08/1990) ?
any idea where the relays would be or where the KE unit would be?
many thanks

 

[television]

If you are unsure about doing this,, there is an easier way.

Remove the live wire from one of the fuel pumps, and run a wire from the battery directly to the pump , then the pump will run if OK

http://www.detali.ru/cat/oem_mb2.as...GM=717.434&CT=F&cat=515&SID=47&SGR=030&SGN=02''

You will find them just behind a plastic panel, on the rear off side of the car behind the rear wheel

 

[johntom]

broken down

Hi everyone
i tried starting the car again today with the idea of listening for the fuel pump. The pump could be heard priming afterwhich the car started and then died. On another occassion the car did tickover (and rev) however it cut out after a few minutes, the fuel pump could be heard for a second after the engine stopped? does this eliminate the fuel system?
many thanks

 

[roofless]

it seems to get fuel & a spark i would check the distributor cap & rotor arm as said by malcolm210 but look for any damp

 

[malcolm E53 AMG]

My IL6 was circa 1988 so I'm not sure whether your slightly later version has a distributor cap and rotor arm, if so the symptoms you describe are exactly like those I encountered and solved by replacing those parts. Quite a common problem with that engine.

 

[television]

Re the fuel pump they do cut, when the system is charged, you could slacken the pipe union where the pipe goes into the fuel distributor to see if fuel comes out

 

[johntom]

broken down

Hi
i have had my local garage look at the car today, (haven't picked it up yet) but they say that rotating the (old style) fuses seems to have cured the problem and that since doing that the car has keep running (several test drives etc) ?
Are there any circuits in the fuse box relevant to the fuel / injection system ? otherwise they haven't cured the problem - it just decided to keep running (i am sceptical has i covered 120 miles in the car before it first cut out) !