help with fuel pressue
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,426
Likes: 1
From: brookville pa.
pressure
klondike there is no blockage in return line as per previous post, i think the prob. was/is spring in reg. was hanging up on the small vac. port that is screwed in to side of reg. it was screwed in so far it was kinda between the coils of spring. hope that was it if not i will figure in out in time thanks for post geo.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
A composite of posts by geogolf
What model of Aeromotive regulator do you have, it isn't a #13105 by
any chance is it?
Any updates on whether the threaded end of the hose barb (for the
vacuum line to the regulator) was protruding far enough through into
the chamber to be interferring with the operation of the spring that
the adjustment screw works with to exert pressure on the diaphram?
Problem solved? If so, by what means?
.
Guys, I took the reg apart again and saw that the vaccum port was
screwed in past flush and was causing the spring not to go into the
diaphram. It was compressing, not against diaphram but against the
vacuum port that was between the coils of the spring. Hope that was
the problem.
I checked the return line, there is no kink. I still think that the regulator
was hanging up when I was trying to drop pressure. Will have to check
tomorrow. I have got to wait for my reg fittings, then I can button her
up and try again.
screwed in past flush and was causing the spring not to go into the
diaphram. It was compressing, not against diaphram but against the
vacuum port that was between the coils of the spring. Hope that was
the problem.
I checked the return line, there is no kink. I still think that the regulator
was hanging up when I was trying to drop pressure. Will have to check
tomorrow. I have got to wait for my reg fittings, then I can button her
up and try again.
any chance is it?
Any updates on whether the threaded end of the hose barb (for the
vacuum line to the regulator) was protruding far enough through into
the chamber to be interferring with the operation of the spring that
the adjustment screw works with to exert pressure on the diaphram?
Problem solved? If so, by what means?
.
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,426
Likes: 1
From: brookville pa.
reg
slalom i think my post says that the vacuum port was screwed in far enough that it was binding up against the spring, if you not having a fuel pressure prob. then i guess that your reg. is ok the only way to check would be to take out the 4 screws and check, the reg. is 13105 the one for a lt1 engine, as soon as i get fuel lines back on and fire her up and see what pressure reading is i will post if that was prob. 2 other cf members kept saying blockage in return line but that was not the case so at this point and time i dont know if reg. was prob. or not hope this helps geo.
Last edited by geogolf; Nov 13, 2007 at 08:46 PM.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Yes, it does. I wrote because I was curious about whether you'd
had a chance to prove/disprove the hypothesis since your last post.
Interesting that you have the #13105.
emo-vet has on-going difficulty with his installation of an individual
runner intake on a '91 L98. He has a #13105, too. Initially, the
problem was lack of pressure (this turned out to be due to a ruptured
hose section joining a high volume pump to the OEM line in the tank.)
Now among several new problems, fuel pressure is too high.
what does red hot glowing header mean ?
HELP,no fuel preasure reading what so ever
He hasn't replied to explain why at one point he reports adjusting
pressure to 30-35 psi and then later reports not being able to adjust
pressure lower than 60 psi.
The reversal in emo-vet's f-pressure circumstances seems hard to
explain. However, I noticed your thread and the suspicion about the
interference between the spring & the threads on the hose barb.
Perhaps there might be a connection?
Did you shorten the threads, order a different hose barb or take
some other corrective action? What leads you to look forward to
an improvement when the lines are back in place and you try starting
the engine?
.
had a chance to prove/disprove the hypothesis since your last post.
Interesting that you have the #13105.
emo-vet has on-going difficulty with his installation of an individual
runner intake on a '91 L98. He has a #13105, too. Initially, the
problem was lack of pressure (this turned out to be due to a ruptured
hose section joining a high volume pump to the OEM line in the tank.)
Now among several new problems, fuel pressure is too high.
what does red hot glowing header mean ?
HELP,no fuel preasure reading what so ever
He hasn't replied to explain why at one point he reports adjusting
pressure to 30-35 psi and then later reports not being able to adjust
pressure lower than 60 psi.
The reversal in emo-vet's f-pressure circumstances seems hard to
explain. However, I noticed your thread and the suspicion about the
interference between the spring & the threads on the hose barb.
Perhaps there might be a connection?
Did you shorten the threads, order a different hose barb or take
some other corrective action? What leads you to look forward to
an improvement when the lines are back in place and you try starting
the engine?
.
Pro
Joined: Jun 2007
Posts: 577
Likes: 0
From: the best car on earth ,vettes are best
his slalom,r.e different fuel preasure settings i mentioned, when car is running 60 psi is the lowest i can get it to stay at,but when engine off and priming and keep key/ignition on it will stay at about 35 psi.
these dam aeromotive fuel preasure regualator dam things,i might have to pull my reg apart to check the spring also like you did geogolf.
thanks
shae
these dam aeromotive fuel preasure regualator dam things,i might have to pull my reg apart to check the spring also like you did geogolf.
thanks
shae
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,426
Likes: 1
From: brookville pa.
reg
emo/slalom the fix is to take reg. apart, nothing in there but a spring and rubber diaphram. and see if port is screwed in to far, fix is just screw it out till it does not hit spring, what i did was once i got port where it was not hitting spring i glued around the outside of it now it cant move. or if you can find a small washer so that it can not be screwed in as far that would work also hope this helps geo.
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Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Another approach is to trim back the threaded end of the hose barb.
These are NPT (pipe) threads and thus there is a taper. For best
seal, NPT threads need to be tight, backing the NPT fitting out of
the hole raises the possiblity of a vacuum leak. Applying teflon tape
to the threads might help a small amount, but placing a washer
between the hex on the barb and the body of the FPR only serves
to lock the FPR in place (with loose threads).
OTOH, trimming the threaded end by sawing, filing, grinding or other
means will remove the interference and still let the NPT threads tighten
as designed. Remove the chamber, determine how many threads
extend into the cavity, remove the hose barb and trim accordingly.
Dress up the shortened end with a file & sand paper, clean, apply
tape or liquid sealant and reinstall.
.
These are NPT (pipe) threads and thus there is a taper. For best
seal, NPT threads need to be tight, backing the NPT fitting out of
the hole raises the possiblity of a vacuum leak. Applying teflon tape
to the threads might help a small amount, but placing a washer
between the hex on the barb and the body of the FPR only serves
to lock the FPR in place (with loose threads).
OTOH, trimming the threaded end by sawing, filing, grinding or other
means will remove the interference and still let the NPT threads tighten
as designed. Remove the chamber, determine how many threads
extend into the cavity, remove the hose barb and trim accordingly.
Dress up the shortened end with a file & sand paper, clean, apply
tape or liquid sealant and reinstall.
.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by geogolf
i will post if that was prob. 2 other cf members kept saying blockage in return line but that was not the case so at this point and time i dont know if reg. was prob. or not hope this helps geo.
Originally Posted by CFI-EFI
Stop and think. What makes fuel pressure in the fuel system? Pressure in ANY hydraulic system, for that matter. My previous post (#6) alluded to it. Pressure is caused by resistance to flow. If it weren't for the fuel pressure regulator providing the resistance to flow in the stock system, gasoline would shoot through the fuel system like the proverbial "stuff" through a tin horn. And with all that rapid flow, there would be almost no fuel pressure. Now apply that knowledge to your fuel system. If there were no resistance to the fuel flow, between the pressure gauge and the fuel tank, you would have no pressure reading. The regulator is an adjustable device that allows you to vary the resistance to the fuel flow and consequentially the fuel pressure. Somewhere beyond where the gauge is connected, you have a blockage, a kinked hose or line, or SOMETHING that is causing all that pressure. Just for giggles, pull the return line off at the tank. Is there any fuel returning? Think of the principles involved and apply some common sense. You'll find the problem.
RACE ON!!!
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,426
Likes: 1
From: brookville pa.
fuel pressure
to anyone that helped, finally got the car up and running, it still runs a little rich but as soon as i time it. hope it will make a difference. the prob. was the spring inside reg. was binding against the vac.port that was screwed into far. thanks for everyones help geo.
Last edited by geogolf; Nov 20, 2007 at 08:52 PM.
