fuel pressure o when hot

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brian88

New Member

Jun 17, 2007

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Jul 15, 2007

#1

• Jul 15, 2007

• #1

88 gt 302 edelbrock carb,brand new holley blue all new an lines, new regulator, filters ,all new painless relay kit to pump. Started up runs good 6lbs pressure, drive it till it gets warm fuel pressure drops to 0, but it still runs like a raped ape, but pressure regulator wont`bring it up???????? I have a gauge on it right next to the carb. Like I said it runs fine even when the gauge is at 0 and the a/f gauge is still reading fine? ANYBODY HAVE ANY IDEAS?????? We did put roller rockers on it but they were adjusted to ford racing specs, and rev to 7000 without problem. Let it set and cool off for 20 min or so pressure comes back. Everything is new ,less than 50 miles on it and was doing it with the old setup to. HELP??? CARB??????

 

bill302

Active Member

Nov 2, 2005

2,131

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46

alabama,gadsden

Jul 15, 2007

#2

• Jul 15, 2007

• #2

do you have the pressure guage installed in the engine bay??

 

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brian88

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Jun 17, 2007

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Jul 15, 2007

#3

• Jul 15, 2007

• #3

yes , it is right next to the carb under the air cleaner , about 3-4 inches above the valve cover.

 

bill302

Active Member

Nov 2, 2005

2,131

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46

alabama,gadsden

Jul 15, 2007

#4

• Jul 15, 2007

• #4

the fuel pressure guage may be crapping out when hot...

 

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brian88

New Member

Jun 17, 2007

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Jul 15, 2007

#5

• Jul 15, 2007

• #5

that is what i was thinking,it is still the old gauge. I just went out and hit the key on ,motor is cold and it was at 6 pounds steady. it will stay there untill you go up the road and it get to operating temp then 0. it did this before when I was runing the in tank pump regulated down to 6,but I had a walbro 255 in it and knew it was a time bomb but that is the way it was when I bought it, but it still did the same thing then, would start out at 6 and then go to 0 and it did not matter where you adjusted the regulator at.That is why I went to all new , with holley blue, lines ,regulator but I did not change the pressure gauge. even before it ran just fine but the gauge said 0.

 

bill302

Active Member

Nov 2, 2005

2,131

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46

alabama,gadsden

Jul 15, 2007

#6

• Jul 15, 2007

• #6

so whats next? you going to change out the guage and see if thats the problem? a new guage is not too expensive thats what i would do...

 

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93lxdm78

New Member

Jun 19, 2007

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Jul 15, 2007

#7

• Jul 15, 2007

• #7

Let me guess here

Is the gauge liquid filled ? If so that for sure your problem get a non-liquid filled gauge

When the liquid warms it expands and will give false readings

my bbk did that

 

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brian88

New Member

Jun 17, 2007

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Jul 15, 2007

#8

• Jul 15, 2007

• #8

I guess I`m outta ideas . do you think the heat could be killing it? it is a summit cheap gauge that is on it. I do not know what else it could be? like i said we turned 7,000 rpm tonight with it at 0 and it didn`t miss a lick at 120 mph. I was mad so I figured it would go or blow!!! it ran great gauge just said 0. it is liquid filled if that makes a difference. A little more info on the car
88 gt
comp cam 5.50 in 5.75 ex. lift 114 lobe seperation
.030 forged pistons,h beam rods
wieand stealth intake,gasket ported
e7 heads fully ported,polished,stainless swirl valves
comp 986 springs
ford racing roller rockers
ford racing pushrods (longer roller rocker versions)
msd everything
bbk long tubes,bbk x pipe
flowmaster exaust
customs brackets for alt and power steering
tremec 5 speed built by tko performance

alot of other stuff , it is all new except for the carb which is about 3 monts old.

 

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brian88

New Member

Jun 17, 2007

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Jul 15, 2007

#9

• Jul 15, 2007

• #9

how should I hook it up? I have it in line spliced into the fuel line between the regulator and carb. Should I run it off of the port on the regulator that I plugged?

 

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brian88

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Jun 17, 2007

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Jul 16, 2007

#10

• Jul 16, 2007

• #10

ordered new air filled gauge today. We will see? Any other ideas welcomed. Thanks to all that have replied !!!!!!!!!

 

EvilHorace

Founding Member

Mar 30, 2001

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0

Milwaukee,WI

Jul 17, 2007

#11

• Jul 17, 2007

• #11

Wow, I've had the same problem with my interior mounted liquid filled fuel pressure gauge too but only if driven on a very hot day. Took about 15 minutes of driving before it went to zero.
I've got the Holley Black pump, large fuel line (10) and up 'til now thought that I had some weird fuel related problem, like improper tank venting (or pump sucking air) when hot or something.
I usually don't drive the 'stang when it's that hot out now (prefer AC cars then) so I havent experienced that in years but I remember being pretty freaked out seeing 0 pressure before getting onto the freeway, thinking I'd need a tow. It also never skipped a beat so obviously it was getting fuel pressure too.
Keep us informed 'cause if the guage cures it, I'll get a new guage as well.

 

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brian88

New Member

Jun 17, 2007

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Jul 17, 2007

#12

• Jul 17, 2007

• #12

Put new gauges on it, not liquid filled ones either just regular ones , one at the carb, one on the other side of the fuel pressure regulator, it was raining so no road test but let it set in garage and get around 190 degrees ., and it was fine even if I opened up the secondaries it was at 5psi at the carb and 8 at the regulator. Can`t wait till the rain stops, slicks do not like rain!!!!!

 

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93lxdm78

New Member

Jun 19, 2007

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Jul 18, 2007

#13

• Jul 18, 2007

• #13

Yeah Thats cool you will be fine now Liquid filled gauges suck. My auto meter fpg is rock on no matter how hot it is.

 

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brian88

New Member

Jun 17, 2007

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Aug 2, 2007

#14

• Aug 2, 2007

• #14

put non liquid filled on it and no more problems !!! Thanks guys !!!