Fuel pump problems?
Discussion
blitzracing said:
You mention you here a click after a few seconds- this tells you a lot. It means the main relay is working- it also means the fuel pump relay is closing at the same time as the main relay, with power from the main relay. This means either the fuel pump relay has faulty contacts or something outside the ECU loom like immobiliser, trip switch or jammed pump.
Great thanks again Blitzracing !Simon
Final update from me: I've checked the voltage states on my car ('92 Griff), and (1) the two relays are wired and colour coded in accordance with the Land Rover 14CUX diagram - dated 1990; (2) there is a permanent +12 Vdc battery voltage to pin 30 of the Fuel Pump relay regardless of whether the Main Relay is in circuit, or not, so the Main Relay is not wired directly in series and does not supply power directly to the Fuel Pump relay; (3) the ECU pin 16 earthing control line to pin 85 of the Fuel Pump relay does depend on whether the Main Relay is in circuit, with the Main Relay in circuit the voltage level stays at about 0V (it does rise slightly) so as to prime the fuel rail until the delay counter times out and then it rises fully to +12Vdc to de-energise the coil if cranking doesn't occur, with the Main Relay removed pin 85 goes immediately to +12Vdc, keeping the Fuel Pump relay Off.
Safe to conclude therefore that the ECU senses when the Main Relay is not in circuit and is responsible for controlling Fuel Pump On/Off, via pin 16, accordingly.
Safe to conclude therefore that the ECU senses when the Main Relay is not in circuit and is responsible for controlling Fuel Pump On/Off, via pin 16, accordingly.
davep said:
Final update from me: I've checked the voltage states on my car ('92 Griff), and (1) the two relays are wired and colour coded in accordance with the Land Rover 14CUX diagram - dated 1990; (2) there is a permanent +12 Vdc battery voltage to pin 30 of the Fuel Pump relay regardless of whether the Main Relay is in circuit, or not, so the Main Relay is not wired directly in series and does not supply power directly to the Fuel Pump relay; (3) the ECU pin 16 earthing control line to pin 85 of the Fuel Pump relay does depend on whether the Main Relay is in circuit, with the Main Relay in circuit the voltage level stays at about 0V (it does rise slightly) so as to prime the fuel rail until the delay counter times out and then it rises fully to +12Vdc to de-energise the coil if cranking doesn't occur, with the Main Relay removed pin 85 goes immediately to +12Vdc, keeping the Fuel Pump relay Off.
Safe to conclude therefore that the ECU senses when the Main Relay is not in circuit and is responsible for controlling Fuel Pump On/Off, via pin 16, accordingly.
Good feedback.Safe to conclude therefore that the ECU senses when the Main Relay is not in circuit and is responsible for controlling Fuel Pump On/Off, via pin 16, accordingly.
Ergo swapping the FP relay with the main relay may not identify a failed FP relay as the pump will still not run and advising not to swap one with the other is good advice
Like I said earlier, I speak from experience of this one having spent time chasing this very fault until replacing both relays and then swapping back each one.Interesting that it appears there are a number of configurations, but then we are talking about TVR.
SMB said:
I had exactly these symptoms a few years back, started , ran for 15 seconds then stopped. Normal failure pattern is just a simple no start, The relays are in the footwell, normally silver with an orange strip over the top. Should be 2 one for ecu one for the fuel pump, normal relays with the same pin out can be used as a get you going but replace with the correct ones Asap or the battery will drain.
Where can I get the "correct relays" from?http://www.racetechdirect.co.uk/m0124-tvr-car-part...
The Bosch part number is 0332 014 112 and available everywhere online but the price from Racetech is very competitive.
The Bosch part number is 0332 014 112 and available everywhere online but the price from Racetech is very competitive.
Hi guys,
Realise this is a very old thread, but just thought I'd add that I bought a couple of those EuroCarParts relays for my Chimaera and they DO NOT have the diode inside them. It's possible to measure this with a multimeter in diode test mode (current should flow in one direction between the two relevant pins, and not the other way) or by taking it apart and looking.
If you're stuck you can remove the diode from a defective relay and fit it into one of these diode-less ones. Takes a steady hand though, and make sure you get it round the right way !
Realise this is a very old thread, but just thought I'd add that I bought a couple of those EuroCarParts relays for my Chimaera and they DO NOT have the diode inside them. It's possible to measure this with a multimeter in diode test mode (current should flow in one direction between the two relevant pins, and not the other way) or by taking it apart and looking.
If you're stuck you can remove the diode from a defective relay and fit it into one of these diode-less ones. Takes a steady hand though, and make sure you get it round the right way !
Gassing Station | Chimaera | Top of Page | What's New | My Stuff