1990 300SL 24v

[Hemmers2]

Hi
The fuel pumps on my 300SL 24v are cutting out at random & stalling the engine . This has now evolved over about 2 weeks to no pump run at all & just an odd click from what I presume is the fuel pump relay ...sound to be on the nearside (UK car ) near the firewall.
How do identify which is the fuel pump relay ?
TIA
Geoff

 

[television]

When the pumps get full of sediment, they can come to a stop.,its no good just fitting a new relay as the high current drawn by the pumps will damage it.

Take off the pumps put the pump end into a bowl of diesel and run the pump backwards, this will clean out all the rubish. Check that it runs forward OK and refit.

Malcolm

 

[Hemmers2]

Pumps & filter are clean & run fine when jumpered to a supply . Problem appears to be intermittent supply from relay to pumps I can hear the relay clicking , chatters some time ...pumps run intermittently in unison with relay clicks
Geoff

 

[television]

Pumps & filter are clean & run fine when jumpered to a supply . Problem appears to be intermittent supply from relay to pumps I can hear the relay clicking , chatters some time ...pumps run intermittently in unison with relay clicks
Geoff

OK , I did not want you to fit a new relay and mess it up.
Find your car here go to electrics and you will find where the relay is.

http://www.detali.ru/cat/oem_mb0.asp?TP=1

Malcolm

 

[Ultymate]

I think what Malcolms trying to say is that it could be the pumps and or filters clogged causing a high current drain which could have caused the failure of your relay and may also similarly affect the new one you're about to fit. The thing to do is fit the relay and check the amps draw at the fuel pump fuse, off the top of my old head I've no idea what it would be on a twin pump set up.

 

[Hemmers2]

Many thanks for the advice ...I appreciate the caution against fitting a new relay & killing that . However I remain convinced that it is the relay coil or the feed to it as, even with the pumps disconnected & the ignition switched on , the relay either clicks in a desultory manner or chatters manically & then dies.

With the pumps connected they natuarlly follow the relay. The engine runs fine in the periods when the relay stays energised .

I'll look up my car on detali & see if I can find the relay ... I have the MB cd for the car but it isn't shown on that at all.

Cheers

Geoff

 

[Hemmers2]

Well ..I'm beginning to wonder if there is a seperate fuel pump relay ...no sign of it on detali or my MB cd

can anyone throw any light on its physical location in the car ?

Geoff

 

[Hemmers2]

Ok ...found the device which incorporates a fuel pump relay ...it's the Engine System Control Module . ...but that wasn't the fault !

I really should have listened to Malcolm ...although the pumps ran ok when jumpered from a supply it still proved neccessary to change out one of them before normal service was resumed ! Still don't understand why the ESCM module was chattering though .

Thanks Malcolm !

Geoff