Relieving Fuel Pressure

[Hobbes992]

Hello fellow Supra owners,

I have an 89 NA 5 speed. I've started disassembly of my engine to replace the HG. Unfortunately I forgot to relieve the fuel pressure beforehand. Is there a way to relieve fuel pressure without cranking the car and removing the efi fuse? The car has been sitting since January... do you think it's possible the fuel pressure might have dissipated on it's own since it's been sitting for so long?

I also ran into a problem when I started taking off the exhaust manifold. So apparently the connection between the exhaust manifold and the pipe running into the cat has only been held together by ONE BOLT!!! :aigo: :aigo: :aigo: And now when I'm having tremendous difficulty removing that one bolt. It's almost as though it's fused to the exhaust manifold. I've used spray lubricant, but it simply refuses to move. I understand the next step involves drilling. Can someone explain how this drilling and tapping is done?

I'm going to post pictures of the destroyed HG when I get the cylinder head off, so stay tuned!

 

[jetjock]

Yeah, I think it's gone by now

Normally you would either pull the fuel pump relay/resistor connector while the engine is running and let it starve or connect a hand vacuum pump to the FPR while the engine is off and bleed it down. As for the manifold bolt you could always just break it off. It'll be easy to repair once out of the car.

 

[Hobbes992]

FPR, I'm guessing that is the Fuel Pump Return? That makes sense, there wouldn't be any pressure at that location right?

 

[Hobbes992]

or did you mean Fuel Pressure Regulator?

 

[jetjock]

Uh, maybe it's me but you should know what the stuff on the engine is called and how it works before you go taking it all apart.

What you said. Think about it. The regulator sends fuel back to the tank depending on how much vacuum is applied to it. By pulling vacuum on it with the engine off it'll open wide and dump what pressure is left in the system. Doesn't matter now though, if your car has been sitting since January there won't be any rest pressure left.

 

[Hobbes992]

Ahh ok thanks. I appreciate your concern, but I'm using this car to actually learn everything. I'm using the tsrm, a haynes manual, and I'm also taking a digital photo of everything I disassemble before and afterward bolt by bolt. And everything is going into labeled bags. This is basically my project car so I'm really taking my time with it. I'm going with the stock Toyota HG for replacement and the head is going to a shop to be worked on so there will be no decking or milling by me, the newbie. You have to start somewhere ya know?

 

[jetjock]

Yeah, I know. I sometimes forget what's simple to me isn't to others. Sounds like you're going about it the right way. Take your time, study, and you'll be OK. Ask if you have more questions and we'll help you out all we can.