Fuel pump help
Discussion
Having been out and about in the S1 (2.8) this morning went out this afternoon to find a flat battery. Charged and reconnected the battery to find the fuel pump running continuously as soon as the battery was connected. I have the bible but hate car electrics so any help or suggestions would be much appreciated.
Cheers
Chris Page
Cheers
Chris Page
Chris,
I take it that you have not found a fuel leak?
I'm not big on fuel injection but going on what I know about carbs, the fuel pump should only deliver fuel to the inlet manifold etc if it needs it. So if is continuosly pumping fuel there may be a leak?
Or...may seem a daft question but is there fuel in the tank? i.e is it pumping air?
I know those first two suggestions may seem daft as by your post you dont mention having the key in the ignition, just having the battery connected causes the problem, but if the fuel pump is running the fuel (if there is any) must be going somewhere, as (Carb experience again...) there are floats or sensors (with fuel injection) that stop the fuel being deliverd if it's not needed.
The aboves worth thinking about, but from what you've said I think you've got some form of loom/electrical fault.
Hope this makes sence?
I take it that you have not found a fuel leak?
I'm not big on fuel injection but going on what I know about carbs, the fuel pump should only deliver fuel to the inlet manifold etc if it needs it. So if is continuosly pumping fuel there may be a leak?
Or...may seem a daft question but is there fuel in the tank? i.e is it pumping air?
I know those first two suggestions may seem daft as by your post you dont mention having the key in the ignition, just having the battery connected causes the problem, but if the fuel pump is running the fuel (if there is any) must be going somewhere, as (Carb experience again...) there are floats or sensors (with fuel injection) that stop the fuel being deliverd if it's not needed.
The aboves worth thinking about, but from what you've said I think you've got some form of loom/electrical fault.
Hope this makes sence?
quote:
Having been out and about in the S1 (2.8) this morning went out this afternoon to find a flat battery. Charged and reconnected the battery to find the fuel pump running continuously as soon as the battery was connected. I have the bible but hate car electrics so any help or suggestions would be much appreciated.
Cheers
Chris Page
Presumably the pump running continuously is what flattened the battery? The fuel pump will be powered via a relay. Perhaps the relay has stuck on? If you can't find which one it is from the Bible, just try pulling them one by one until you find the right one.
Cheers,
Peter Humphries (and a green V8S)
quote:
Chris,
I take it that you have not found a fuel leak?
I'm not big on fuel injection but going on what I know about carbs, the fuel pump should only deliver fuel to the inlet manifold etc if it needs it. So if is continuosly pumping fuel there may be a leak?
Dave H,
Fuel electronic fuel injection usually has pressure relief valve at the end of the fuel rail which works roughly thus: 150 psi fuel pump supplies fuel to fuel rail, 50 psi pressure relief valve at end of fuel rail which allows 100 psi fuel to reurn to the tank via return fuel line. (figures I have used are just for example). Obviusly the high pressure to the fuel rail is for when all injectors are firing at high rpm.
Jas.
Thanks for the help and suggestions. Have just managed to get round to groveling around in the passenger footwell and removed the little black box labelled fuel pump relay (in this case a Lucas FDB502) and note immediately that the face with the terminals has experienced some serious heat and melted. Whether this is cause or effect I won't know until I replace it.
I'll keep you posted. Thanks again for the help.
Chris
I'll keep you posted. Thanks again for the help.
Chris
Just coming back to finish this one off as I managed to get some unexpected benefit out it which may help someone else. I received a replacement pink engine run sensor the terminal numbers matched the Lucas unit but not the TVR wiring diagram. Fitted it and absolutely nothing so resorted to my friendly neighbourhood auto electrician who diagnosed the replacement as defective and repaired the Lucas unit as a temporary fix. Sent the pink chap back and received another replacement which looked identical but this time the terminal numbers matched the wiring diagram. Fitted it and everything now runs fine.
The twist is that ever since I bought the car it has always started 1st time but generally takes a good few turns and you have to open the throttle to get it going as if it was flooding. No matter what I did I couldn't overcome the problem. The new relay doesn't have the problem and it now starts 1st turn and no throttle. The differance between the two relays is that the Lucas unit had a priming sequence to it when you turned the ignition on but the new one doesn't. So it would appear there are two specifications of engine run sensor and you have to get the right one.
Sorry it's a bit long winded but I hope it might help someone in a similar situation.
Thanks again Guys
Chris
The twist is that ever since I bought the car it has always started 1st time but generally takes a good few turns and you have to open the throttle to get it going as if it was flooding. No matter what I did I couldn't overcome the problem. The new relay doesn't have the problem and it now starts 1st turn and no throttle. The differance between the two relays is that the Lucas unit had a priming sequence to it when you turned the ignition on but the new one doesn't. So it would appear there are two specifications of engine run sensor and you have to get the right one.
Sorry it's a bit long winded but I hope it might help someone in a similar situation.
Thanks again Guys
Chris
Mark,
The relay fitted was a Ford part and the only number on it is on the opposite end to the terminals - 68 125 unfortunately there is no part no. listed on the invoice. The terminal numbering was the main differance and on the fitted unit it goes 31,15,87,1,30 whereas the Lucas unit and the defective Ford unit goes for the same terminals 31,15-11,54-15,1-3,30-28.
Hope thats of use.
Chris
The relay fitted was a Ford part and the only number on it is on the opposite end to the terminals - 68 125 unfortunately there is no part no. listed on the invoice. The terminal numbering was the main differance and on the fitted unit it goes 31,15,87,1,30 whereas the Lucas unit and the defective Ford unit goes for the same terminals 31,15-11,54-15,1-3,30-28.
Hope thats of use.
Chris
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