fuel pressure

[1redjet]

I am wanting to check my fuel pressure but am unsure of what the pressure should be. How much pressure should I have?

[chads84svo]

My svo at idle is about 42 psi. If you start turning up the boost you got to turn up the fuel pressure.probly should get a adjustable fuel pressure regulator. This way you can set the fuel pressure to what mods you do.

[1redjet]

I believe I have an adjustable fuel pressure regulator somewhere in the garage. I m just trying to get it running right now and wanted to male sure I had adequate pressure. It will start with starting fluid. I am going to put a gauge on it tomorrow and see what pressure I have at the rails.

[chads84svo]

Sounds like it's not getting fuel............fuel pump dead? Or filter could be totally clogged with crud.

[1redjet]

Is the filter in the tank or inline?

[1redjet]

I can hear the pump.

[chads84svo]

Your gonna Probly have to drop the tank. Screen could be clogged or the filter.Maybe the pump is wining but not pushing the gas too the motor. Ya never know. Ya.......you got to find out if you have fuel pressure. Bet you dont.

[1redjet]

I guess I will go ahead and drop the tank. What will I need to install a walbro 255 lph pump? Is it just drop in and go or will I need to do some modifications?

[SchoolBoy]

Stock fp should be 40psi and it should increase with boost I believe.

[bleavitt23]

39-40 psi with the vacuum line disconnected - this is the base fuel pressure. With the line hooked up it should be in the lower 30's at idle, depending on how much vacuum you're getting at idle. And yes, it should raise 1:1 with boost pressure, from the base pressure (for example, at 10 psi of boost, fuel pressure should be around 50 psi).

[1redjet]

What is needed to swap the stock pump to a 255lph pump?

[1redjet]

Did the 79 come with a mechanical pump or electric? Reason I am asking is that I see mechanical pumps on eBay for the 79 2.3. Not my engine is from a 88 TC. So I was wondering if they had to swap in the in tank pump.

[boboli]

79 cars were carbureted, so the eBay pump won't work.
A 255 pump is not a direct fit. You usually have to change the connectors to the pump because aftermarket pumps don't accept Ford's connectors. It's not hard, but it's not a direct swap

[1redjet]

I realize I cannot use a mechanical pump. I was wondering if the 79 2.3 pace car originally came with a mechanical pump. If so then that would mean the previous owner added the in tank pump.

[Jimmy2.3Mustang]

The 79 should have been a mechanical pump. It's hard to say what the previous owner did during the conversion. I seem to remember that the EFI gas tanks won't bolt in the early Fox bodies. You might have aftermarket fuel system parts, or some conglomeration of factory parts like the early SVO setup with a lift pump, and a high pressure pump to boost the feed to the engine. At least you know the TC tanks won't fit the Mustang body at all, and the fuel pump hanger is completely different too.

I wouldn't worry too much about having the exact spec fuel pressure, usually you can tell if it's a problem by just pressing the schrader valve. If it squirts it's pumping fuel, if it doesn't it's not. If it squirts that should be enough to at least get the engine to start and idle. Contrary to popular belief, oldschool EFI cars like these will start and idle with the fuel pressure really screwed up.

[chads84svo]

Maybe that's why it doesn't run.Maybe they couldn't figure out the fuel situation. I thought you said you could hear the pump running in the tank? If you can then it was probably was changed...........but done correct? You won't know till you drop that tank.

[1redjet]

I can hear the pump kick on. I know I really need to get the tank dropped and see what is going on. I am going to try and see if I have any fuel at the schrader valve in the morning. The had the car running after the swap. However it has not been tagged since 03. Probably just a bunch of junk in the line.

[chads84svo]

To stop it from running that would take alot of junk in the lines.lol. Ya never know. I'm very curious to what it looks like in that tank. Check the fuel filter too.

[1redjet]

I am hoping for good weather tomorrow so I can check some stuff on it.

[chads84svo]

Wish you were just down the road.......I would love to check that pace car out. Hope you get it running.After a paint job that is gonna be a sweet pony.

[1redjet]

You could always take that svo on a nice road trip! I wish some of you guys were close. It would be great to have some hands on help with this.

[chads84svo]

Lol............little to far for me but we will all help as much as we can. Drop that tank!!!!! Lol

[Jimmy2.3Mustang]

A few years ago my brother in law had a 5.0 91LX that just died in traffic. Didn't take long to figure out there wasn't any fuel pressure. The pump was still coming on, but no pressure. When I pulled the fuel pump and hanger assembly out of the tank, I could see the rubber hose from the pump to the sending unit had rotted and blown out.

Just treat it like a no start/no run condition and work through it. See if the Schrader valve has pressure, loosen the distributor hold down clamp and with the key in the run position turn the distributor back and forth and you should hear the injectors click on and off. Should be able to tell if you have fuel pressure and injectors firing by pulling the spark plugs and looking/smelling for raw fuel. Next I'd look at the ignition system, check for spark at each plug while cranking the engine. If you've got fuel and fire, take a good look at the cam timing, timing belt, etc to make sure they're all set right. These cars couldn't possibly be easier to work on, the problem should be clear without too much troubleshooting.

[chads84svo]

Well said..........

[1redjet]

If it quits snowing I am going to tear into it today.