Please help confirm the relays pictured - G60.

[Riley 0]

Hello fellow corrado owners/enthusiasts... :D

 

I need to know two things from the below picture...1992 G60.

 

1/ Which is the fuel pump relay?

2/ Which is the ecu relay?

Edit: 3/ Where is the fuel pump run on relay?

Edit: 4/ Where is the x-relief relay and what the hell is it?

 

Thanks,Neil.

 

[ProdigalSon 1]

Hi Riley,

 

This may help...

 

1992 Fuses and Relays.jpg[/attachment:14iwkrej]

[Yandards 0]

Right ho.

 

1. Fuel pump relay is in the bottom right hand corner (position 12), numbered 80.

2. ECU relay is in position number 3 and is numbered 32 on your pic, the number I have in the elec manual is 53 but it may be superseeded by 32.

3. The fuel pump run on relay is located in position 16 which is on top of the fusebox directly above position 4, should be numbered 9.

4. X relief relay is at position 4 and numbered 18. This provides a relay control for a variety of electrical consumers, e.g. the windscreen wipers, air blower, heated rear window all use the x relief relay.

[Riley 0]

Guys, thats superb thanks a lot :D

I had that diagram somewhere but lost it!

 

Yanards, i don't understand the fuel pump run on relay...as i have none at all above the fuse box iirc :?

Its not at the passenger side is it? But i thought they were abs relays or sommet?

 

Thanks again guys :D

 

Neil.

[ProdigalSon 1]

The fuel pump overrun relay may have popped out of its clip and fallen down to the rear of the relay/fuse panel - the upper two rows of relays do not plug into a panel, but into the wiring harness itself, and they are held together with clips that affix to the actual relay board (the bottom two rows). They can jump out of the clips and fall to the rear of the panel, even though they are still firmly connected to the harness and working correctly...

 

If you can hear the fuel pump whirring after getting out of the car then you do have a relay fitted :)

[ProdigalSon 1]

FYI: The fuel pump overrun ensures that the pressure in the fuel rail exceeds 2 bars for at least 10 min after the engine is turned off, to aid quick starting during that period.

[Riley 0]

Oh man! That is brilliant!!! :D Cheers mate :) The fuel pump does run, although the after run has stopped working.

 

My car has great fuel pressure, but when turned off...that pressure drops off instantly!!! I think you have just helped me a lot there :D

 

Ive had the fuse box out in the past and can't remember seeing them hanging around i don't think :?

 

And im hoping that the fuel pump relay does more than just power the fuel pump, such as doing something when switching between open/closed loop maybe?

 

Neil.

[Supercharged 2]

Those are quite old mate - ECU relay is now '30' and Fuel Pump should be '167'

 

I think the fuel pump run-on is controlled by the control unit near the expansion tank on ABS cars.

[mattkh 0]

And im hoping that the fuel pump relay does more than just power the fuel pump, such as doing something when switching between open/closed loop maybe?Neil.

Hi

Why, what are you experiencing ?

[mattkh 0]

FYI: The fuel pump overrun ensures that the pressure in the fuel rail exceeds 2 bars for at least 10 min after the engine is turned off, to aid quick starting during that period.

Hi

Are you saying that the fuel pump should buzz away for ten minutes after turning the ignition off ???

[ProdigalSon 1]

Glad to help :wink:

 

Don't think the fuel pump overrun relay does anything else. The pressure in the inlet manifold will modulate the pressure in the fuel rail though. Under boost conditions, the excess pressure in the manifold causes the FPR to increase from 2.0 bar to 2.5 bar to provide fuel enrichment (alongside the electronic fuelling map in the ECU, which controls how long the injectors stay open). The FPR is purely a mechanical process, and requires that the couple of inches of thin 'vacuum' hose from the inlet manifold to the top of the FPR is in good condition.

 

On a related topic, if you are losing pressure from the rail and find that you do actually have a fuel pump overrun relay fitted, then it points to a broken fuel pressure switch - this is mounted on the right side of the manifold and fed from a rubber fuel hose from the right-hand end of the fuel rail.

 

HTH.

[ProdigalSon 1]

FYI: The fuel pump overrun ensures that the pressure in the fuel rail exceeds 2 bars for at least 10 min after the engine is turned off, to aid quick starting during that period.

Hi

Are you saying that the fuel pump should buzz away for ten minutes after turning the ignition off ???

The fuel pump doesn't have to run that long normally - usually just 10 seconds or so to re-pressurize the fuel rail, but you will hear it cut out and come on intermittently during that 10 minute period, while it ensures that the fuel rail is reasonably pressurized - the fuel pressure switch controls this process, and I think it activates the overrun when the pressure in the rail drops below 1.2 bars IIRC.

[ProdigalSon 1]

Those are quite old mate - ECU relay is now '30' and Fuel Pump should be '167'

Yes, I appear to have original relays with those numbers too...(!) :oops:

 

I think the fuel pump run-on is controlled by the control unit near the expansion tank on ABS cars.

Could be, mine is ABS, but I think I do have a relay in that position above the fusebox... can't check though as my car is at the bodyshop for some cosmetic improvements (read respray :clap: )

 

Does that control unit include relays or just fusing?

[Supercharged 2]

Right, got that slightly wrong - the FP run-on is controlled by the Rad Fan control unit in the engine bay indirectly as it activates the 'Fuel retardation relay 90' which all G60's should have in position 14 (clipped above position 2 on the main fusebox)

[ProdigalSon 1]

Makes sense, good call Supercharged :)

[Yandards 0]

Right, got that slightly wrong - the FP run-on is controlled by the Rad Fan control unit in the engine bay indirectly as it activates the 'Fuel retardation relay 90' which all G60's should have in position 14 (clipped above position 2 on the main fusebox)

 

..and that info in the self study guide you have just used is not quite correct either, the fuel run on relay is the same thing as the fuel retardation relay.

 

So to clarify as Mr 'charged has no doubt confused the issue: ;)

 

The fuel pump run-on relay is used to ensure good hot/warm starting behaviour. The relay is numbered 90 and should be found above position 4 (position 16)on the fusebox using a clip on the base plate that the relay attaches to.

 

The fuel pump relay (the relay that activates the fuel pump when the ignition is switched on) can be triggered by the fuel pump run-on relay, is numbered 80 and can be found at position 12 on the fusebox.

 

The control unit for the fan run-on relay is found at position 15 (according to the wiring diagram manual for a 1992 G60) and is numbered 31. This relay is active when the ignition is off and is triggered by a thermo switch located near the inlet manifold on a bracket, the operating level for this thermo switch is +90 degrees C. This in turn enables the radiator cooling fan to run in its low speed mode and will also provide power to the fuel pump run-on relay. After approx 2 minutes the fuel pump run-on relay makes a connection that allows the fuel pump relay to be energised as long as there is a minimum of 1.2 bar of pressure in the fuel system (The sensor for this is attached the connection that comes from the end of the fuel rail at the tb end) this will then allow the fuel pump to re-establish full system pressure of around 2 bar. This cycle only occurs for up to 10 minutes after engine switch off due to a timer integrated into the control unit for fan run-on relay.

 

The reason for the 2 minute delay and the minimum requirment of 1.2 bar prior to the operation of the fuel pump relay is to ensure that there are no leaks in the fuel system. So to summarize, the control unit for the fan run-on relay is built into the relay and is triggered by the thermo switch, the fan run-on relay then energises the fuel pump run-on relay which in turn will provide power to the fuel pump relay if the operating conditions of a minimum of 1.2 bar fuel pressure are present. This cycle can only occur for up to 10 minutes after the ignition is switched off.

 

I hope that clears all of that up.

 

As for the fuel pump relay doing anything aside from powering the fuel pump, it doesn't.

 

That is all

[ProdigalSon 1]

Class dismissed! :salute: :lol:

 

Cheers, Yandards, excellent explanation, as usual :notworthy:

[Riley 0]

And i can indeed confirm all the above as correct after doing some testing. :D

 

Cheers guys, really helpfull info there and explained nice and concisely. :)

 

I think my fuel pump run on problem is the switch on the end of the rail (can't believe people do away with it tbh) as i tried a spare relay (which was indeed located above fuse box :) )

 

There was no fan run on relay there though, but that does actually work anyway...wherever the relay is :?

 

Im gutted the fuel pump relay does nothing else except power the pump, it was my last and only hope to cure a 3 year running problem :( Apart from knock sensor (but which makes no differnce when unplugged anyway)

 

I guess some of us have learnt sommet new there anyway :)

Thanks again...and it was worth a shot i suppose :cry:

 

Neil.