lasercowboy
familyman;117380 wroteA mechanic I spoke to mumbled the fuel pumps should come on for a second or two after turning the key to ignition, but before cranking. I can't remember if that happened before this fault or not, but it's not happening now. Is he correct?
Definitely.
familyman
Removed the relay cover to be 100% sure. Watched it while turning the key.
Position 1 - open/rest
Position 2 (ignition) - latched closed
Position 3 (cranking) - open/rest
Slowbrick
Yeah LH2.4 should prime each time you take the key from off to Run. So you are saying that's not happening now?
Also I wonder if you are getting injector pulse. With the key set to Run and in park, if you rotate the engine slowly by hand can you hear the injectors fire?
familyman
This makes zero sense.
1. Ignition on, fuel pump relay activates, but fuel pump doesn't come on.
2. Apply external 12V DC to in-tank fuel pump, in-tank pump comes on, and pumps fuel.
3. Bridge fuse 4 & 6, connect external source of fuel to main pump, can hear main fuel pump working and see bottle empties of fuel.
Unless... Does ONLY the main fuel pump come on with the relay (and the in-tank pump ONLY comes on later once the engine is running)?
familyman
No priming - pumps always silent when turning the key. They only come on when I either bridge fuse 4 & 6, or, apply 12V to in-tank pump at it's socket.
Time to work out how to turn the engine by hand, LOL.
Slowbrick
LH2.4 should momentarily run the pumps when you turn the key to prime the system. They won't run unless the engine is rotating and that's a safety feature to prevent a fire in the event of an accident so that behaviour is normal.
If you crank the engine then both pumps should run.
familyman
Nope, not coming on when cranking. And the relay is on with dash lights, but then unlatches when cranking too.
Slowbrick
Ok so something is wrong with that. What happens if you jumper 4 & 6 and then crank?
familyman
Forget... I'll do it now.
familyman
4 & 6 = at least the main pump running (I can never hear the tank pump over the main pump. The only way I know it works is by a) measuring voltage reaches it's socket when 4 & 6 are bridged, and b) applying an external 12V to the tank pump).
When cranking no change - can hear (at least the) main pump running (see above, LOL).
familyman
Crankshaft turny time.
Slowbrick
Hmm that is interesting. So you have pumps running with 4 & 6 and cranking, it runs on lighter fluid which indicates you have spark. Let us know how you go turning the motor by hand. Should be a 24mm socket. If not I've had luck just grabbing the power steering pulley and turning that.
familyman
I know the car isn't starting atm, but is it normally safe to turn the crank with a socket, with the ignition on?
carnut222
familyman;117394 wroteI know the car isn't starting atm, but is it normally safe to turn the crank with a socket, with the ignition on?
Why are you turning the engine by hand? I still suspect fuel pump relay. Do you have a known good one you can swap in?
carnut222
PS this must be a very frustrating experience! Hope you figure out what the issue is soon as it's killing us all! :)
familyman
Well, I don't know for certain the tank pump is coming on when jumping 4 & 6. I'm just assuming, because I haven't worked out a way to hear it over the main pump, without running the tank pump off it's own power source. Can I pull the wires off the main pump, and have the tank pump still run (so I can hear it with 4 & 6 jumpered) - or another way to disable main pump?
Slowbrick
carnut222;117395 wrotefamilyman;117394 wroteI know the car isn't starting atm, but is it normally safe to turn the crank with a socket, with the ignition on?
Why are you turning the engine by hand? I still suspect fuel pump relay. Do you have a known good one you can swap in?
I had a very peculiar issue with my own 240 where the fuel pump relay would engage properly, the pumps would run and I had spark. When I turned the engine by hand I had no injector pulse. Ended up being a break in the harness bulkhead for the injectors was damaged. Fixed that and we were golden.
carnut222
Have you disconnected the fuel feed at the fuel rail to see if fuel pumps out while the pumps are running?
familyman
I don't have a spare relay. But bridging fuse 4 & 6 bypasses the fuel pump relay.
Turning engine by hand to see if I can hear injectors trigger.
Slowbrick
familyman;117397 wroteWell, I don't know for certain the tank pump is coming on when jumping 4 & 6. I'm just assuming, because I haven't worked out a way to hear it over the main pump, without running the tank pump off it's own power source. Can I pull the wires off the main pump, and have the tank pump still run (so I can hear it with 4 & 6 jumpered) - or another way to disable main pump?
Intank should get it's power from fuse 6. The relay sends power to fuse 4 and has a small lead that goes to fuse 6. If you can power up fuse 6 from a switched source and remove the fuse from 4 then the intank should run and the main shouldn't.
