255 Fuel Pump Do I Realy Need A Adjustable Fuel Pressure Regulater??!!

fish254 said:

i am going to upgrade to a 255 pump the question can not use a adjustable fuel pressure regulater???

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Please translate into english for me. What are you saying/asking?

It takes a lot of mods to "need" an adjustable regulator. The correct fuel pump and injectors will handle a wide range of mods. If you or your tuner decide you need one, get a Kirban.

no

I have a 255 in my tank and I don't have an afpr

Grady

final5-0 said:

I have a 255 in my tank and I don't have an afpr

Grady

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but don't you have a tweecer? Why would you need one? Just curious......

-James

Fuel pressure ain't controlled by the 'puter. Its kinda one of those things you gotta set at the beginning kinda like base timing. You can tune to adjust for fuel pressure that's off, but that's kind of a band-aid fix.

i have a 255 also, and a stock reg

grngt50 said:

but don't you have a tweecer? Why would you need one? Just curious......

-James

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Yes I do James

But, that is not the issue.

W A Y too much attention is placed upon fuel pressure in the Stang community
if you ask me.

Upping the pressure can make a difference just after you make the change
but
The pcm can and most likely will try to dial back some fuel over time

This has been covered many times here and on most other sites so I won't
waste everybody's time.

Bottom line is the pcm has the ability to sense ... not the pressure ....
but the fact the elevated pressure has caused an over rich condition.

By moving the pressure up and down ........
you may get yourself in one of those Catch 22 kinda things

You move the pressure and immediately see some improvement
but
You have to wonder
will the mechanical adjustment ... hold steady ???

I myself have never had an afpr
but
I have talked to several other self tuners who have

They have told me they can see the pcm dialing back pulse width if
they up the pressure

Summing up here with these closing thoughts

You have two basic parts in your tune

1) Driving around town conditions which is the Closed Loop part
2) WOT conditions which is the Open Loop part

When you up the pressure the pcm will compensate in both areas
but ... as I understand it ... the Closed Loop will be effected first
and over a some what longer amount of time ... Open Loop can be
effected as well.

Thus ... self tuners usually won't change the pressure for fear of
making their tuning efforts null and void

Sooooo ... Self Tune or Not ... the pcm ... Works like it Works

Grady

thanks for the explanation Grady! But if our computers like to dial back the pulse width after time, why do they even bother selling the adjustable FPR's for our cars? I bought one like six months ago and noticed an improvment. For me improvment = less pinging. Of course this was coupled with a new 190 fuel pump.

-James

I'd first start answering your own question by advanced searching this topic in just the 94-95 tech. and then maybe all 5.0 ... i'm 100% positive you're going to find plenty of reading material. read it all and make up your own mind. based on the information you find there.

Grady's right... he sums up what he says up there well but more in depth you need to search the many threads and opposite decisions people have. or else this thread will turn into another one. or if they've been through this discussion before people will just glanse over and not respond at all.

R.J. and Grady both speak wisely.

Other hand... i threw in a 255lph when my pump went south and left the 19#ers, then finally up'd to 24#rs w no afpr and ran strong... check sig. and yes now i have one.. .more for future upgrades and ability to afford at the time i have it set to whatever the stock reg would be. i'd say don't waste your time yet.

grngt50 said:

thanks for the explanation Grady! But if our computers like to dial back the pulse width after time, why do they even bother selling the adjustable FPR's for our cars? I bought one like six months ago and noticed an improvment. For me improvment = less pinging. Of course this was coupled with a new 190 fuel pump.

-James

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Let me ask you a Q and see if it might make you think along a different path

Just cause something is made available to purchase
Does that always make it justified as being a good thing in every case

See what I mean my friend ???

There is truth ... and ... There is the whole truth

Does an afpr give you the ability to force more fuel ... Yes

Then ... there is the ... rest ... of the truth
and
That is what we are talking about here :Word:

When you understand how stuff works
then
N O B O D Y can blow smoke up A N Y of your orifices

Grady

cowboy.....I've searched this topic for several hours, but thanks for the tip about using the search. lol....thanks grady......I'd like to keep my orifices smoke free lol

-James

Very good stuff from Mr Grady and company.

Be a little cognizant if searching that the Fox III's handle the WOT trim (and use of O2's) just a little bit differently as I recall. You might read a fox III tidbit that isn't quite correct for an 5N95 processor.





To be explicit, if you were running way lean (like your injectors are at 100% duty cycle) and the puter wanted to run richer but couldnt, higher FP could help you get extra fuel in there.