junkyard racer

Car is finally running. Seem to be having fuel pressure issues. Sometimes it will read a steady fuel pressure of around 4psi but then it will drop off to 0. It will only read a steady fuel pressure after it has sat for a while and on initial start up. I have yet to be able to raise my fuel pressure above 4psi, according to the gauge. I can mess with the (new) holley fuel pressure regulator but that seems to do nothing for me. Its acting as if the FPR is non-existent. Running down the highway, it will run just fine. City driving, forget it. After about 30sec of idle, and then back on the gas under load, it will studder and die. New carter fuel pump also. Also, does the amount of fuel running through the filter seem as if its enough fuel? To me, it does not.

youtube video:
http://www.youtube.com/watch?v=E2dWy10to_U

t_g_farrell

iTrader: (1)

Two things. I have the same setup includig the Carter pump and Holley regulator.
I have one of those Summit 0-15 psi liquid filled gauges as well. The gauge
only works well at initial startup then its will seem to read zero after driving a
bit but I can tell the pressure is good and its running right.

1. Almost all pressure guages are only really accurate in the middle 25% of their
ranges. This means on a 15 psi range its probably only accurate from 6 to 9 psi
or so. At either end it can be off significantly. I know mine is. I adjusted my pressure
by ear for now by just turning it down and then slowly upping it until I heard the
idle change, then I backed it off a bit and left it. The guage said it was at less than
2.

2. A del will only run well with a maximum of 2.5 psi. Anything over that and it will
run silly rich and never get a good idle because the pressure overwhelms the
needle seat. So 4 psi is too much, dial it back some.

Its ok if there some air in the glass filter your showing in the video. Mine does that
at times. I think the pump backs off when you deadhead the fuel supply and it
picks back up when the pressure drops again.

If your pump is too noisy and theres a lot of air in that filter you might want to
try adding a fuel pump relay and a hot lead from the pos battery terminal so the
pump gets a good 12v. The pumps gets noiseir the less voltage it sees.

trochoid

iTrader: (6)

Holley has 2 basic fprs, 0 - 4-1/2 and 4-1/2 - 6 psi. You have the first one. I always run the out line to the carb out the side, never the bottom.

junkyard racer

Great info. Really sucks that the gauge is that bad. Interesting that you mention they run great at 2.5psi. That is what I had it set at first, but I thought I read someplace that racing beat recommended 4psi. My car did run great at ~2.5
The way my car is set now, its probably flooding the engine. It does smell pretty bad, but my biggest fear is leaning the engine out and it going kaboom. I will back it off a bit and try it again. Also, the upgrade for the voltage is on the agenda. Thanks!


And you tell me I have my fpr hooked up incorrectly. Is it incorrect or is that how you just run it? I almost swear that there is a "in" and a "out" ...the way I have it connected. Guess I will swap that around also and give it a shot.

RotorMotorDriver

iTrader: (1)

On mine the inlet is the bottom and the outlets are the two sides.

~T.J.

EDIT: Just watched the video, yours looks right to me? The line with the gauge is the output of the regulator and looks like its coming off the side, and the inlet is the bottom. Are you setting your pressure while the engine is running?

junkyard racer

Yes, I am. Mine is set up identical to yours. Clean engine bay too!

RotorMotorDriver

iTrader: (1)

I had problems with my regulator when I first installed it. It would hold pressure and creep up to max pressure on me and dump fuel out of the booster venturis on the carb. I tried different springs, new diaphragms, etc. I was Googling around about the pump and regulator, and a LOT of people have had problems with the Holley regulators it seems (Ive had 4 in the past with no problems, this was the first). Anyway, someone said it could be something in the regulator (manufacturing debris and crap) thats causing it to stick open (or jam closed).

I finally lucked out and got it to work by blowing compressed air into the fuel line where it connects to the carb and the other end disconnected before the pump. Basically, I blew out the whole line and regulator of any debris and crap that could be in there, and reset the diaphragm via air pressure. Seems to have worked because I havent had any problems since but Im not holding my breath after all the fighting I did with that thing...

~T.J.

trochoid

iTrader: (6)

My error, had to dig a spare one out and check. Bottom in, sides out. Sorry for the misinformation.

junkyard racer

I turned the fuel pressure down to 2.5psi and she screams. Seems to have a little hick up at 30mph after I mash the gas, but I think that will have to be sorted out by messing with jets and so forth. I am also going to do the direct fire mod, so that may also help.

Thanks for your input. I appreciate it.