d'oh, pie on my face. This isn't simple at all.
I've got both pumps out and disassembled:
The lift pump is on the right, the high pressure pump is on the left, and the plastic housing that it came from is on the far left. The 2 pumps are VERY similar in size. The height difference doesn't matter so much. But what does matter is the small lip near the top of the lift pump. It prevents the pump from fitting in the plastic housing all the way to the bottom. That means I can't attach the pickup screen to it, and the pump can't pickup fuel from the bottom of the tank (ie. I end up with an empty tank before it's actually empty). I could probably find a way to force it down there, either with heat or brute force. But the odds of causing permanent damage to the housing go up, and servicing the pump in the future becomes a nightmare.
So as far as I can tell, my options are:
- force the pump to fit (bleh)
- re-use the old high pressure pump and add a pressure regulator under the hood
- get rid of the in-tank pump and add an inline diaphragm pump under the car
I'm favoring nitec's idea of adding a pressure regulator, but my main problem with this is that I need a bypass regulator, not just a basic regulator. Bypass regulators are much more expensive than basic ones. Setting up the bypass isn't a problem, there's already a return line right next to the feed line under the hood. But now I'm looking at buying a bypass regulator, fittings, a tee, clamps, and a gauge... easily $100 for good quality parts.
Meanwhile, a good quality inline lift pump is easily $80 and requires me to add wiring to make it work.
Conundrums...
