Fuel Pump Fuse 25a Blowing

[colley340]

The initial message was deleted from this topic on 25 July 2012 at 18:15

[Griffinr]

I think in the first instance you need to have a good look around at the wiring for signs of damage and also check connectors for tightness and corrosion, particularly the earths. If your main earth deteriorates then the starter will try and draw current through any other metal connections to the engine such as the throttle cable. I recently had occasional stalling that turned out to be the main battery earth, it looked OK and took the starter current but the crimp was loose so occasionally went open circuit on the relatively small running current.

Rob.

[colley340]

Hi Rob,

All wiring 'looks' as it should although ive not checked the earths yet. With regard to the S2 should i only consider page 1 of 2 in the following wiring diagram? If so this simplifies the problem as there is only the fuel pump on this circuit and associated relays.

http://www.tvrsseries.com/drawings/tvrswiringdiagr...

Im more concerned about putting a new starter on it and then it going again hence why i need to determine whether the two issues are connected or not.

Regards,
Gareth.

[colley340]

Just checked fuel pump wiring and is all ok with no breaks. Also pretty sure it's not fuel pump or the relay as it clicks in ignition. After reading up on the wiring it seems that a big red wire near ecu feeds both fuel relay and engine run sensor. What else connects to engine run sensor as this may blow the fuel pump 25a fuse. Taken starter motor off and that's definitely knackered still not sure if they are related. Thanks

[colley340]

Anyone have any experience of similar faults as i am still struggling to locate the faulty component or wiring. Double checked and its definately the fuel pump 25a fuse going intermittently when driving. Seems to idle ok had a good 10mins stable idle with fan kicking in then after driving for 5mins fuse went again then after replacing and setting off again went within 2 minutes.

Regards,
Gareth

[phillpot]

Not a five minute job but think I would try wiring a new temporary feed to the pump (with a fuse in) from a good feed, or even direct off battery, to eliminate pump from the equation (or prove it is the pump).

[Top Gear TVR]

I had a fuel pump go on a 190e, it did the very same thing to begin with.........idle ok, warmed up and then once on the dual carraiageway - popped the fuse.

Might be worth checking earth leakage on the pump? or simply just swapping it out if you can lay your hands on one.

[Le TVR]

Does the fuel pump relay power any other circuits like on the 2.8??
What is the condition of the inside of the relay? They are notorious for getting wet and disintgrating.
Best is to leave the fuse out, connect a 12V bulb between the fuel pump supply wire and the battery +.
Give all the wiring a pull and if the bulb lights you've found the short.

[colley340]

Thanks guys im having a play today with a friend who knows a fair bit about electrics. We are wiring in a complete new feed from the relay to the pump as its fairly easy and at least i know its good for future. I will then have a look inside the relay and see whats it like. I also had a look for this yellow connector which someone suggested to me behind ignition cowl but there isnt one there?

Not sure if relay powers anything else as such, i think the fuel pump wiring goes into a fuse box then splits out of the other side to power fuel pump relay and engine run sensor on 2.9? Think!

Thanks for all your input,
Regards Gareth.