Fuel Pump problem
460 280GE LWB 1987
Over the weekend my 460 developed what I think is a fuel pump problem.
On Friday morning I covered a 60 mile trip, no problems of any sort, then after lunch it would not start, it has never failed to start in the 3 years I have owned it.
Working on the basis that it is either a fuel or ignition problem, I first removed the fuel input pipe at the injector and switched on the ignition, no fuel coming thru, next I tried to locate the fuel pump, working back from the filters, found and removed an inspection plate on the bottom of the fuel tank which covered the pump. Again switched on ignition and listened to pump, completely silent. Next checked if pump is receiving electrical power, the circuit diagram shows brown to earth and black with pink/white strips as live, I could not get a reading between the live terminal and earth, I then tried connecting a spare battery directly to the pump terminal and earth, nothing.
I could not find the fuel pump relay.
Any suggestions? Do I need a new pump?
Thanks
When you turn on the ignition you should hear the pump run for 20 seconds or so - if not then it's probably the relay. remove the cover to the right of the steering column, the relay is in there, and try again - you should hear the relay click - if it does then check for broken wires to the pump - if no click, check fuses and suspect the relay. You can take out the relay and bridge terminals 30 and 87 to make the pump run continuously.
There is a switch on the fuel distributor which activates the fuel relay when the engine is running. It detects the movement of the air flap in he fuel distributor housing. You need to disconnect the switch (pull out the plug from the connector) to allow the pump to run with the engine off. You will hear the relay click when the plug is removed from the connector.
Surprised that the direct connection to the pump didn't make it work.
Just be carefull conecting 12 v to the fuel pump - disconnect the wires first as 12volts back through the relay will probably blow it. The fuel pump, although theoretically 12v is designed to work around 7.2 and there is something electronic in the relay do deal with this.
Ideally you should probably take a fuel pump and a relay with you...
try eurocarparts for prices.
Did you try to start it again or can someone in france try? I say this because when the relays start to go the fault tends to be intermittent - it might well start after an hour or so.
Again if there is no power at the pump for about 20secs when the ignition is turned on then suspect the wiring or relay.
Take a multimeter with you! The connection you made was probably not good enough. Remove that plug to the distributor and turn on the key, the pump should start and continue. When they start to wear out a common fault is that they stick. Turn on the key and give a gentle tap from a light hammer to help get it going. A pump would be expensive new, maybe some wrecking a 280 will have one you could take with you.
Euro Car Parts:
Fuel Pump £128.55 +VAT part # 441 22 0010
Relay £81.99 +VAT part # 451 22 0020
Both parts in stock, a bit surprised at the cost of the relay :cry: , but pump seems reasonable :) .
That's still alot of money to blow before you know the problem, but I gues you can't go to France with nothing. At least you know you will be able to repair it. Otherwise you need a trailer. Or pay for recovery
Agreed, I think it is probably the relay that’s at fault, when I get back will have go at returning the pump and getting a refund, otherwise will pop it on the parts for sale forum.
BTW, found this useful site on Bosch Jetronic
Good website. I have the original MB engine (car) manual if you are interested, its 2" thick and heavy
Yes, if it is for the M110, then i would be interested.
PM me with details.
I have been thinking about getting the full set from:
Hi James
Sorry to hear about your problem. I have a similiar problem but my 460 petrol 280 G seams to be working but . I think I will need a new fuel pump as there is petrol leaking out of the solid metal of pump part that connects on to the hose that leads up to wards the regulator and filter. Now I know what is the price .
Was under the car for the last few minutes with FIXWIN on the line . He always has all the great advise .
I am going to price it tomorrow in Euro if by chance I get a better price I will pm you .
Does anybody know the part number ?
Sorry I just saw that you gave the part number
Success, G back on the road. :D
First tried the new relay, no joy, :( so went ahead and installed new pump and filter.
Tried again, still no joy :? , removed relay and bridged 87 and 30, now can hear pump and she starts on the button.
Smell of fuel, the pump is spraying fuel from the out union same as umhloti, just tighten and all is well.
THX dentsmithy and Roly, I would never have even found the relay, never mind bridging the terminals without your help.
I tightend mine also and it seams to have done the job all seams well for now . Regards and thank you all .
new washers (not sure what they are, copper/brass?) also help achieve a better seal there...
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THX dentsmithy and Roly
Will try your suggestions next at the end of the month. The problem is that the G is now stranded at a friend’s house in France, so I will only have limited time next bank holiday to indentify and correct the fault. The house is in the sticks with no internet connection so no immediate feedback if your advice above does not resolve the problem, so further suggestions more than welcome.
Would the direct connection have confirmed that the pump itself is working? I connected some domestic flex from the live terminal to positive on the spare battery and the battery negative to the exhaust pipe, so cannot guarantee the connection was sound and did not want to mess about too much with sparking under the fuel tank.
Should I bring a spare pump, just in case? Are they expensive?
Cheers
James