fuel relay can i get rid off it? or can i bypass it, it keeps melting and cutting out
04-05-2011, 08:34 PM
#1
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fuel relay can i get rid off it? or can i bypass it, it keeps melting and cutting out
as above iv gone through 2 now and getting sick of it, can i put a swith live to the pump instead of it?
it tryed it without the relay and a live feed to the black and red wire which is the live for the pump and it started fine.
i never drove the car like that but would it cause problems somewere else?
there nothing worse than having a nice looking classic car that you have to push through a town center and looking like a total twat which happens alot in rst as you all know, i dont think there is a day without the bonnet being open lol
any advice or diagrams pics etc.... on how you got to sort it out would be great
thanks diesel
it tryed it without the relay and a live feed to the black and red wire which is the live for the pump and it started fine.
i never drove the car like that but would it cause problems somewere else?
there nothing worse than having a nice looking classic car that you have to push through a town center and looking like a total twat which happens alot in rst as you all know, i dont think there is a day without the bonnet being open lol
any advice or diagrams pics etc.... on how you got to sort it out would be great
thanks diesel
04-05-2011, 08:53 PM
#2
you need to check the wiring to the pump sounds like you have a poor connection which is causing heat in the relay. or replace the wiring to the pump.
Last edited by luke19790_3; 04-05-2011 at 08:59 PM.
06-05-2011, 02:08 PM
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This was discussed on seriesoneforum, someone on there came up with the following give it a try...
The OE relay is fed permanently by a 3mm thin wall red cable and the power flows out down the 3mm thin wall black/red wire. The rest are small thin signal wires for earth, ignition feed and tachometric signals.
Right, a small technicality. The OE relay needs the red wire for power otherwise it won't work. This means we can't just disconnect it and put it straight onto another relay. We also need a signal to switch the other relay.
1, So starting the job, I cut down the 5 way plug on the base of the OE relay to remove the 2 thick wires (red and the black/red). It's worth noting that once this is done, it essentially becomes a 3 way plug that can now be fitted either way around. So make sure you know which way to plug it back on.
2, I cut the old spade terminals off and cut back any burnt wiring/insulation. On the black/red, I crimped on a large yellow spade terminal and plugged it onto a 4 pin relay (terminal number 87, not 87a or 87b which some relays have).
3, Taking the red wire, I also crimped a large yellow spade terminal but on this, I inserted a smaller 1mm thin wall red cable crimped into the same terminal (1 thick wire for main supply and 1 thin wire to power the OE relay). This tail of wire then had a smaller blue spade terminal that was plugged onto the OE relay where the red wire was originally connected to (terminal 30). The larger yellow spade was then connected to terminal 30 of the 4 pin relay.
So up to now, we've moved the permanent live (red wire) to a new 4 pin relay, bridged from this wire to the original connection on the OE pump and moved the switched output (black/red) from the OE pump to the new 4 pin relay.
4, So now we need to earth the new 4 pin relay. A simple 1mm wire from terminal 85 to the chassis is fine (there is an earth point above the speaker pod).
5, Now we need a signal to switch the new relay on. A straight piece of wire from terminal 86 on the new relay going to the original terminal that the black/red was on will do the job.
What will happen now is, the OE relay will behave as normal but instead of feeding the pump directly, it merely switches another relay which in turn takes the entire load and not the OE relay. Everything will behave as normal except for the reliability which will dramatically increase!! The terminals won't get as hot and the relay won't melt!
If anyone needs a diagram, I'll try and does one later but I have to go out and rewire a Cosworth engine loom now so don't have time.
----------------------------------------------------------------------------------------------------------------------------------
What i did was just do it differently.
I did not cut the OE relay plug and effectively destroy it, I simply cut the red and red/black wires half way up the wire length and put in female bullet connectors. I then got a universal relay holder that the new relay sits in and put male bullet connectors on. This way, if you need to put it all back to 'as was' you can do so very easily and without any fuss. Also, with the relay plugs still in tact, you can’t get the wires round the wrong way. I did measure just under 13v at the fuel pump with the original wiring but as TONY C said above, I put in a new feed wire to it and also upgraded the earth wire to it too.
I am now hoping that all this will now resolve all the possibilities of the fuel pump relay circuit from breaking down in the future. The OE relay is now just effectively a very low voltage switch for the new relay.
Hope it helps am going to do this to mine in the near future..
The OE relay is fed permanently by a 3mm thin wall red cable and the power flows out down the 3mm thin wall black/red wire. The rest are small thin signal wires for earth, ignition feed and tachometric signals.
Right, a small technicality. The OE relay needs the red wire for power otherwise it won't work. This means we can't just disconnect it and put it straight onto another relay. We also need a signal to switch the other relay.
1, So starting the job, I cut down the 5 way plug on the base of the OE relay to remove the 2 thick wires (red and the black/red). It's worth noting that once this is done, it essentially becomes a 3 way plug that can now be fitted either way around. So make sure you know which way to plug it back on.
2, I cut the old spade terminals off and cut back any burnt wiring/insulation. On the black/red, I crimped on a large yellow spade terminal and plugged it onto a 4 pin relay (terminal number 87, not 87a or 87b which some relays have).
3, Taking the red wire, I also crimped a large yellow spade terminal but on this, I inserted a smaller 1mm thin wall red cable crimped into the same terminal (1 thick wire for main supply and 1 thin wire to power the OE relay). This tail of wire then had a smaller blue spade terminal that was plugged onto the OE relay where the red wire was originally connected to (terminal 30). The larger yellow spade was then connected to terminal 30 of the 4 pin relay.
So up to now, we've moved the permanent live (red wire) to a new 4 pin relay, bridged from this wire to the original connection on the OE pump and moved the switched output (black/red) from the OE pump to the new 4 pin relay.
4, So now we need to earth the new 4 pin relay. A simple 1mm wire from terminal 85 to the chassis is fine (there is an earth point above the speaker pod).
5, Now we need a signal to switch the new relay on. A straight piece of wire from terminal 86 on the new relay going to the original terminal that the black/red was on will do the job.
What will happen now is, the OE relay will behave as normal but instead of feeding the pump directly, it merely switches another relay which in turn takes the entire load and not the OE relay. Everything will behave as normal except for the reliability which will dramatically increase!! The terminals won't get as hot and the relay won't melt!
If anyone needs a diagram, I'll try and does one later but I have to go out and rewire a Cosworth engine loom now so don't have time.
----------------------------------------------------------------------------------------------------------------------------------
What i did was just do it differently.
I did not cut the OE relay plug and effectively destroy it, I simply cut the red and red/black wires half way up the wire length and put in female bullet connectors. I then got a universal relay holder that the new relay sits in and put male bullet connectors on. This way, if you need to put it all back to 'as was' you can do so very easily and without any fuss. Also, with the relay plugs still in tact, you can’t get the wires round the wrong way. I did measure just under 13v at the fuel pump with the original wiring but as TONY C said above, I put in a new feed wire to it and also upgraded the earth wire to it too.
I am now hoping that all this will now resolve all the possibilities of the fuel pump relay circuit from breaking down in the future. The OE relay is now just effectively a very low voltage switch for the new relay.
Hope it helps am going to do this to mine in the near future..
11-09-2012, 05:53 PM
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I don't think I ever got round to doing a diagram to be honest, but it is simple to do. If you read that in front of the relays it is pretty self explanatory.
Edit!!
I did! It is on he thread over at S1Turbo forum. You might have to register to see it...
http://www.seriesoneturbo.co.uk/showthread.php?t=5995
Edit!!
I did! It is on he thread over at S1Turbo forum. You might have to register to see it...
http://www.seriesoneturbo.co.uk/showthread.php?t=5995
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