Hi, Have problem with fuel pump wiring. Pump is not activated when ignition switched on. When bridged on fusebox works fine and engine starts. Have checked wiring and problem seems to be that there is no 12volt supply to socket 15 where ignition switched on. Wiring diagram in Haynes north very helpful but seems that the back with from the ignition switch carries the 12v to the pump relay. Any assistance very much appreciated. Thanks
Hello there, what fusebox have you got in there the early one with the ceramic fuses or later CE1 blade fusebox
Its the Ce1 blade fusebox I removed the fuel pump relay and inserted a relay with the number 18 on it. When ignition switched on fuel pump ran and engine started. Checked the fuel pump relay. Put 12 v across it, it clicked and there was continuity between connections 87 and 30 which are the pump connections. Seemed to work ok but only when the switched 12 volt was connected to pin 15. Does not work if connected to 31. Have checked the fuse box (position marked 2) and found as follows: Pins 3 and 2 (87 and 30 on relay) work ok Pin 5 (relay pin 1) connects to coil negative. Pins 4 and 1 (relay pins 15 and 31) both run to earth. When I got the car the fuel injection had been removed and replaced with an SU Carb. The wire from the fuse box to the pump had been cut out and had to be replaced. Not sure if any other wires were cut out. When the ignition is switched on there is no 12v to either position 15 or 31. Or does this only work when the engine in being cranked or running and triggered by the coil? Again thank you for your assistance
if the 18 relay runs the pump when fitted in slot 2 then you know the fuel relay socket is fine on the earth, ignition, live and output sockets. the issue is down to the red/black rev counter trigger from the coil negative to D/26, or your relay is dead
Thank you for your assistance Very much appreciated. Have checked the continuity from the coil negative to position 5 on the fuse box (position 1 on the relay that I have) and it all seems to be in order. Engine fires up so coil is working. Could I have the wrong coil? It certainly is not the original and the ballast resistor is there but not connected. Whist I am writing I have another electrical problem. Engine fires up but ticks over far too fast. (approx 2,500 rpm) Have run the following checks on the thermo time switch and cold start valve. Find as follows: THERMOTIME SWITCH. Removed the plug. Red/black wire has 10/11 volts when engine cranking Green/white runs to earth. COLD START VALVE. Removed the plug. Red/black has 10/11 volts when engine cranking. Cranked for over 30 seconds and still had the same voltage. Green/white rune to earth. I noted from an earlier post that the cold start voltage should switch off after about 8 seconds. Mine certainly does not Am I correct in thinking that the thermotime switch needs replacing Any advice very welcome Thank you
try unplugging both the CSV and TTS, if you still have earth on the green/white then something isnt right with the wiring loom as tyhe TTS is what providesn the earth path for the gree/white when cold. have a look behind the fusebox, there is a 2 pin plug with both the red/black andf green/white wires in for the cts/tts. the red/black spade should have a wire to the headlight loom for cranking power, but the green/white spade should be empty. with the fuel relay, pin 15 needs ignition livwe which you tested for and foundf was dead, but yet when the 18 relay was swapped in it worked ok, whioch uses the very same ignition live feed from the fusebox that the fuel relay needs... So it sounds liek the fusebox might have a loose or dirty contact on the terminal 15 socket?
HI, Did exactly as you suggested. Unplugged both the CSV and the TTS and checked continuity to earth. No connection to either. Neither were running to earth. Ignition was off when I did this. Both red/black wires did however show a connection to earth. I did start the engine and when I restricted the flow from the auxiliary air valve behind the cold start valve the tick-over did slow down appreciably. Not sure where to go from here. Any suggestions very much appreciated. Thank you
ok sounds good wirign wise, as a last check you should see continuity between the green/white pins on the tts and csv, and cranking live to the red/black pin on both of these. with the coil if the car has electronic ignition (3 pin plug on dizzy) then you dont need a ballast resistor, so double check what you have is an electronic ignition coil. of it has points ignition then usually it wont have a balast resistor eraiter, instead there is a purple/white resistance wire from the fusebox to supply a reduced voltage with tickover being high it might be an air leak or base idle is set high, suggests this is so since when you pinch the AAV pipe it goes down. the aav does have a little adjustment in it also, if you look inside it should be mostly open when stone cold then will gradually close up as the heater inside warms up. idle adjustment is via screw on the rear of the throttle body, itrs worth pullign the screw out to check the rubber oring on it while you're there and go over all the vacuum system to make sure all is well, look at the boots inside the folds for splits, etc.
Thank you so much for your continued help. Will do as you suggest. There is a purple/white wire from the fuse box to the coil but there is also a black wire to the same side. This is 12v ignition switched. Is this correct. If not is it ok to find the clown that wired the car and have him shot???? Again, thank you. Cheers
I should have added that I have fitted a contactless 'Powerspark' Electronic ignition system. At the moment it is connected to the coil with just the black 12v switched wire. The engine starts ok. I have not connected the purple/white wire. Cheers.
that sounds correct yes, you would need to check the spec of the coil to make sure it is happy with full 12v power plus it is suitable for electronic ignition system
