It's been a while since adding to this thread!
Ever since the head gasket job and general project creep in the engine bay, the car just hasn't seemed quite right! Hard starting when cold and very reluctant to start when warm. I'd basically left the car unused for extended periods as I didn't want to drive it with something not quite right, not helped by the demands of a young family.
It was a bit of a process of elimination which I think I've finally resolved over the past weekend. I was pretty sure the car was getting a spark as all the major components, including the cam angle sensor, had been replaced with new prior to the gasket work. The car also had a new fuel filter and injectors installed and a new old stock fuel pressure regulator with the head gasket work, so I though fuel supply should be OK. More recently, I noticed that the fuel pump didn't sound quite right, the tone it made seemed to change pitch and sometimes it was quite, whilst other times it seemed quite loud. So I assumed that the pump was on the way out and sourced a replacement uprated pump. I found time to install the new pump this weekend. Not quite a direct fit as the inlet and outlet are clocked slightly differently, so it's sitting at a slight angle, but otherwise it's fine.
I put the pump assembly back in the tank and turned the key. Lots of cranking but no start! At this point I was a little miffed!
I took the pump out again and rechecked the wiring and electrical continuity, all good. Briefly applied 12 volts to the terminals on top of the assembly and the new pump worked, so the actual fault seemed to be electrical. I put the pump back in the tank, hooked up some clear PVC hose to the outlet to confirm if there was any flow, connected the wiring and turned the key, again no pump action!
I had checked the voltage at the wires supplying the pump previously and had a little under 12V, so there was power, but not enough current to get the higher capacity pump running, so the only thing left to look at was the relay! So I swapped out the fuel pump relay with the one that powers the mobile phone connector, crossed my fingers and turned the key once more. The pump primed, the car spluttered a bit, ran rough for a couple of seconds and then settled into an stable idle.
I'm now confident I've finally fixed the car, it just needs some fresh fuel and the interior put back together, and then a good clean. I wouldn't be surprised if the relay failing was the primary cause of the head gasket failure as I know it was running lean on a few occasions due to high revving. I was pretty sure there weren't any major vacuum leaks.
It's pretty annoying thinking that a $20 relay has caused all this hassle, but on the bright side, I now know that most of the active components in the ignition system and fuel system are essentially new. All I need to do now is install the closed loop IC and O2 sensor I have waiting, pity my car doesn't have the necessary wiring in the loom, that's a job for another day.
Now I just need to drive the thing more!
Knowledge is realizing that the street is one-way, wisdom is looking both directions anyway