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Author Topic: fuel pressure and regulation  (Read 15088 times)

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f85gtron

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fuel pressure and regulation
« on: September 28, 2014, 12:43:05 pm »
I suspect my fuel pressure regulator is failed, had failed, is frozen. I'm running pig-rich, hooked up the winaldl, cts and mat are good. O2 int is around 152+ and the map is reading good. No codes set, but am getting a lot of rich flags.  I haven't made my weekly trip harbor freight either to pick up a fuel pressure tester yet.   I haven't measured vacuum at the fuel pressure regulator yet because my wife is watching me closely and i can't get in and out before she notices, so I'll have to do that tomorrow.
It's been rich since day one, but now it's obscene because the cat is missing. I suspect it's as a result of a high flow 255 fuel pump that the manufacturer sent me after sending me three bum pumps in a row and threatening a return for refund.....
I usually run about 15# vacuum. Is that normal?
What can i do to change the pressure, assuming the fuel pressure regulator is good. I've read about adding a penny to the spring, but what about decreasing pressure?  File down the spring? 
Any adjustable regulators that are mo' better?
Ron
edited to fix elementary spelling errors and sentence structure.
« Last Edit: September 28, 2014, 12:51:28 pm by f85gtron »
85 GT manual NOW powered by 7730
3.4 bored to 3.5, cammed out and DIS'd
F23 connecting power to ground
My wife won't ride in it. It's "the other woman" ;)

Fierofool

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Re: fuel pressure and regulation
« Reply #1 on: September 28, 2014, 09:40:30 pm »
Refresh us on the fuel system.  HP fuel pump, but how about the injectors?  What are they?  Stock? 

Overpressure should go back to the tank via the return line. 
There are three kinds of men:

1.    The ones that learn by reading.
2.    The few who learn by observation.
3.    The rest of them have to pee on the electric fence and find out for themselves.    Will Rogers

f85gtron

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Re: fuel pressure and regulation
« Reply #2 on: September 30, 2014, 05:19:05 am »
It's got rebuilt injectors that have been rated and balanced to 16.2 lbs.
I snuck out with my son and pumped down the regulator with a vacuum tester and it appeared to be slowly leaking down. I then "manually" applied vacuum and tasted gasoline vapors, but didn't get a mouthful of gas, so i guess it's time to change the regulator out.
I have hard starts when warmed up, so i suppose the writings on the wall.
I still haven't checked fuel pressure yet.
85 GT manual NOW powered by 7730
3.4 bored to 3.5, cammed out and DIS'd
F23 connecting power to ground
My wife won't ride in it. It's "the other woman" ;)

Fierofool

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Re: fuel pressure and regulation
« Reply #3 on: September 30, 2014, 07:28:19 am »
So that's what that device is for.  I always thought it was for getting boogers out of my little grand daughter's nose. 

I have a good fuel rail with regulator that I can bring along if you want. 
There are three kinds of men:

1.    The ones that learn by reading.
2.    The few who learn by observation.
3.    The rest of them have to pee on the electric fence and find out for themselves.    Will Rogers

f85gtron

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Re: fuel pressure and regulation
« Reply #4 on: September 30, 2014, 11:51:58 am »
Sure wouldn't hurt. I've got a duke sitting here. Do you want any parts in trade? (Other than door hinges and that plastic piece that covers the aldl connector.....those are spoken for)
85 GT manual NOW powered by 7730
3.4 bored to 3.5, cammed out and DIS'd
F23 connecting power to ground
My wife won't ride in it. It's "the other woman" ;)

f85gtron

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Re: fuel pressure and regulation
« Reply #5 on: October 03, 2014, 12:15:12 pm »
Fierofool, thanks for the rail!  I took my rail off and energized the pump, no leaks from the injectors.  Good. I took off the old regulator.  Bad. It had a chunk of something rubber, like a gasket or oring. I guess that explains the low pressure. I went ahead and replaced the regulator with the one Fierofool supplied and its good as gold.
85 GT manual NOW powered by 7730
3.4 bored to 3.5, cammed out and DIS'd
F23 connecting power to ground
My wife won't ride in it. It's "the other woman" ;)

Fierofool

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Re: fuel pressure and regulation
« Reply #6 on: October 03, 2014, 06:40:41 pm »
If you still have the old rail, would you bring it to me at the picnic?  The other rail I had in the box is a Camaro rail that uses the same regulator.  I can pull it and put it in your old Fiero rail or use the Camaro rail if I ever get around to doing my 7730 swap. 
There are three kinds of men:

1.    The ones that learn by reading.
2.    The few who learn by observation.
3.    The rest of them have to pee on the electric fence and find out for themselves.    Will Rogers

f85gtron

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Re: fuel pressure and regulation
« Reply #7 on: October 03, 2014, 08:45:18 pm »
Sure. I'll bring it.
85 GT manual NOW powered by 7730
3.4 bored to 3.5, cammed out and DIS'd
F23 connecting power to ground
My wife won't ride in it. It's "the other woman" ;)