Fuel pressure drop with increased throttle (Page 2/5)
fierobear JUN 26, 09:51 PM

quote
Originally posted by fierofool:

Optimally, fuel pressure should be above 40 psi at idle. The stock regulator is set at 43.5 psi and that's what it should provide when the fuel rail is primed without the engine running. After the engine starts, ideally, the pressure shouldn't drop below 38 psi. With it sitting as long as it has, there's probably a bunch of sediment in the tank. We lost a set of injectors after a car had set for about 4 years, and even a fresh fuel filter didn't prevent the superfine particles from passing through and clogging the inlet to some of the injectors.




I drained all the old fuel when i changed the pump, and made sure the tank was clean.
fierobear JUN 26, 09:53 PM

quote
Originally posted by wftb:

Did you put in a new rubber line that goes from the the pump to the line that runs to the injector rail hardline? they look good untill pressure builds up and then they leak and bleed off pressure.




I replaced all of the rubber lines on the back of the tank with new parts, including the two curved hoses that go to the gas fill.
fierogt28 JUN 27, 03:08 AM
I think buying a 'cheap' fuel pump wasn't a good idea.

For the 88 Formula, get an AC Delco EP378 which is the stock fuel pump.

You can always connect a mechanical fuel pump gauge to the fuel Schrader valve to find out the fuel PSI pressure.
Should be between 40-46psi.

I'd clue its the fuel pump.

------------------
fierogt28

88 GT, Loaded, 5-speed.
88 GT, 5-speed. Beechwood interior, All original.

Patrick JUN 27, 03:45 AM

quote
Originally posted by fierobear:

I replaced all of the rubber lines on the back of the tank with new parts, including the two curved hoses that go to the gas fill.



I'm not sure you actually answered the question, as I believe wftb was referring to the short piece of submersible hose in the tank.


quote
Originally posted by wftb:

Did you put in a new rubber line that goes from the pump to the line that runs to the injector rail hardline? they look good untill pressure builds up and then they leak and bleed off pressure.
fierofool JUN 27, 08:16 AM

quote
Originally posted by fierobear:


I drained all the old fuel when i changed the pump, and made sure the tank was clean.



We did, too. Even took a water hose and washed the tank out. It was horrible inside. The water coming out after rinsing was nice and clean.

Installed a new pump and screen and removed the pulsator due to bad seals in it. Not only did we have to replace the injectors, but the new Bosch pump failed, too. MikeMac then rinsed it with a commercial wash.

fierobear JUN 27, 01:30 PM

quote
Originally posted by Patrick:

I'm not sure you actually answered the question, as I believe wftb was referring to the short piece of submersible hose in the tank.

[QUOTE]Originally posted by wftb:

Did you put in a new rubber line that goes from the pump to the line that runs to the injector rail hardline? they look good untill pressure builds up and then they leak and bleed off pressure.


[/QUOTE]

There is no rubber hose inside the fuel tank, at least not this one. The pump mounts directly to the pulsator, which mounts directly to the hard metal line.

FYI, this is all on a brand new Fiero Store sending unit setup.
fierobear JUN 27, 01:32 PM

quote
Originally posted by fierofool:


We did, too. Even took a water hose and washed the tank out. It was horrible inside. The water coming out after rinsing was nice and clean.

Installed a new pump and screen and removed the pulsator due to bad seals in it. Not only did we have to replace the injectors, but the new Bosch pump failed, too. MikeMac then rinsed it with a commercial wash.



I plan to order the AC Delco pump, at worst I'll have one on hand for the next reclamation project. I’ll inspect the tank for contamination and corrosion when i change the pump.
Patrick JUN 27, 03:36 PM

quote
Originally posted by fierobear:

There is no rubber hose inside the fuel tank, at least not this one. The pump mounts directly to the pulsator, which mounts directly to the hard metal line.

FYI, this is all on a brand new Fiero Store sending unit setup.



Ah, you still have a pulsator with the new setup. That's where most Fieros these days now have a short piece of hose installed instead... hopefully submersible hose.
fierobear JUN 27, 04:22 PM

quote
Originally posted by Patrick:

Ah, you still have a pulsator with the new setup. That's where most Fieros these days now have a short piece of hose installed instead... hopefully submersible hose.



I figured it might be a year specific thing. 88 is definitely pulsator.
Patrick JUN 27, 05:47 PM

quote
Originally posted by fierobear:

I figured it might be a year specific thing. 88 is definitely pulsator.



Actually, it's a fuel pump specific thing. The earlier years originally had pulsators installed as well. I forget the name of the style of pump from the factory, but a pulsator was required to reduce/eliminate pulses in the fuel pressure. The newer style fuel pumps don't produce these same pulses in fuel pressure, therefore pulsators have mostly become redundant. That's what I've read here over the years anyway.