Understanding the electrical components on the carby of a '92 GQ RB30.
Team, I'm trying to track down an odd starting issue that only affects the vehicle when it is parked facing uphill on a reasonably steep slope. To this end I'm checking the in-tank fuel pump delivery circuit.
I've tried to run the fuel pump by turning the ignition key on to IGN, or the engine running position after starting. I had read that in this position the fuel pump should energise and deliver fuel to the filter. It doesn't!
Reading some more, it seems there is another switch in the circuit that controls when the fuel pump runs. Since the vehicle runs fine once started, and starts perfectly except when on steep uphills, the pump does work, so there must be a switch somewhere that determines when it runs.
Looking at the carby, there are three devices on the carby that have wires running to them, so perhaps one of those is the trigger I'm missing. I've read oen might be a heating element for cold weather starting, and that it can be isolated if need be.
So, my initial goal is to have a better understanding of what these three electrical devices are, and if one of them does indeed switch the pump, I would like to know which and verify its operation.
My ultimate goal is to make the vehicle start well on any slope, and my gut feel right now is fuel or carby, because nothing else mechanically or electrically really gives a toss if the vehicle is horizontal or otherwise.
I had hoped to measure the fuel flow rate and delivery pressure at the fuel filter when the vehicle was uphill and horizontal, hence my desire to get the fuel pump running on just the key switch rather than when the engine is running.
I have read on here about a solenoid in the fuel return line that is RPM activated, but my return path doesn't seem to have such a device fitted, or at least not in the location discussed, ie near the grille on the driver's side.
A bit more detail is that I can start the vehicle on a hill, but if I don't rev the crap out of it for 30 seconds, the moment I let the revs subside, the thing stalls and is a bugger to start for the next 30 minutes. I'm thinking it starts well off the fuel in the float bowl, but that fuel is not being replaced without a tonne of revs.
I've tested the pump by putting 12V to it directly and it flows fuel. I've blown out the supply line to the filter and it is clean. It doesn't starve for fuel when driving, so I don't believe I have a blocked fuel filter or lines.
Any help would be greatly appreciated. Not having 25 posts or more yet, I'm not allowed to download the manuals (admin rule) so I'll try and soldier on with your input and a bit more trial and error.
As a last resort I'm thinking of doing the EFI from a VL upgrade, but that too requires a switch for the fuel pump, so I may as well get my head around this control system for my own use now and in the future.
Cheers.
