91 z-28 350 crate vortec tpi.

i bought a holley AFPR and installed it. when i turned on the engine the pressure would come up then slowly drop off. thinking it was bad i ordered another one and put it on and it did the same thing. so now i call holley and they tell me 'it is suppose to do that'. since they built it i figure they must know what they are talking about. (the pressure stay up with the old unit)

now i go to set the fuel pressure and it seems that it will only go up to about 28psi and stops. no matter how much further in i turn it the pressure will not go up. now i am thinking my guage must be bad so i adjust to about where it think it should be and go order a new accel rail mounted guage.

by the way, does anyone know how to put the map sensor back on with this guage on??????

back to my story. the guage came in so i go out and install it and go to adjust my fuel pressure. what a shock the guage only goes to 28psi and it will not go any higher. if i adjust it out the pressure will drop, but once i adjust it up to 28 psi that is all it will do. i mean i cranked this thing in about 2-3 turns with no effect!!

just in case your wondering, yes i did unplug the vacum line from the AFPR and did plug that line.

anyone got a suggestion or should i go ahead and finish my sentece about the holley AFPR piece of s___?

 

mine worked without a problem... maybe you put it together wrong or something... i dunno? =\

 

i know a doulbe major doesn't make me a mental giant but it would be hard even for ME to screw this up.

also, how could i put the tpis AFPR together correctly but mess 2 of these up?

 

=\ i dunno... my next door neighbor had a 5.0 formula and bought a holley afpr as well... dont ask me how, but he managed to put it on incorrectly

 

i would wonder but the old tpis unit held pressure fine and could be adjusted. the only reason i don't put it back on is because one of the seals was starting to come apart. i was working on something else and just happened to find it so i got the holley.

i would also wonder about the check ball but it was all installed new and like i said, it held pressure with the old AFPR.

man, i'm stumped.

one question, does your unit 'bleed' back down with the key?
i.e. turn ignition on, fuel pressure guage goes up. when you don't start the car does it still hold pressure?

 

OH NO, not again!!!!!!!!!!!

 

geez bob, i'll just leave your emails here!!! lol

i am afraid it is more like......still. just can't seem to exorcise all the demons outta this thing.

when i get this thing dialed in it should be truly amazing. i mean i am smoking the tires like mad with 2.73s in the rear! after i get this AFPR straight i am going to

A. get a shift kit installed
B. get some 3.23s or 3.42s in
C. undecided

HAVE A GREAT FATHER'S DAY!!

 

did u check ur fuel filter. maybe its clogged ?

 

mine did that also........i installed a new walbro 255/lph fuel pump and it corrected it......just a thought..........

 

thanks guys, i guess anything is possible but......

fuel pump has about 2k on it and the same with the fuel filter. also keep in mind the tpis unit worked fine except for the problem with part of the diaphram starting to peel. that was why i replaced it. new one is on the way. i ordered a crane and found out non of the insides come with it. oh well!! live and learn.

 

Did you check the pressure with the vacuum line disconnected? If it wasn't, that could also be your problem. It will only go up so high with the vacuum line attached....

My first AFPR looked just like the Holley unit (IIRC it has to be adjusted with an Allen Wrench). The Set pressure was always adjusting itself. Since I was able to get it from GM it was about half the price of the Holley unit. Then again. that was 6 or 7 years ago. I don't have a part number anymore but I got it from Fuel Injection Specialties. They may have the part number listed on their website.

 

yep, vacum line was off, but thanks anyway.

ps JEGS SCREWED ME OVER. i ordered another part, paid to have it overnited by noon next day. well at 12:15 i called to see where it was and was told that it was only supposed to be overnited not by noon.

well pardon me but the guy quoted me 29.95 on shipping and told me it would be here by 12noon. so i ask if i was charged for by noon and she told me no i was charged 20 for overnite. ok, i can deal with that.

so after taking a day off from work and waiting all day i call back at about 5:20 asking where the h e l l it is. she tells me it was put on HOLD!!

now why counld't they call me and tell me this? why couldn't they bother to mention it when i called at lunch?

needless to say i told them to forget it. hello? summit?

 

you may have damaged your pressure regulator. The rubber seak could be broken or the spring / rod or base could be damaged. I ruined 2 of these myself by overtightening the bolt, they break easy. Compare yours to the condition of a new one. AFPR should give you stock pressure whith the bolt or dial lightly tightened.

 

i am batteling with holley afpr as well. i ve had it on for a year, but recently got a guage so now i can adjust. first night at races that i played with it, i lost fuel pressure, down to 28, car barelly runs. took it apart, found the check ball is turning freely around on its axis, so the flat side comes around and thus, fuel pressure lost.

so, why is the check ball have a flat side? is there supposeed to be a spring in the socket behind the ball to stop it from moving? mine might of felll out. i have no clue on how to fix this ball from moving, is this your problem also. goning to try holley tech support on monday, but can anyone help?

 

Don't run the Mid America Motorsports Billet unit either. The vacuum line port is too wimpy. First time you nudge it, it breaks off.

 

Holley seems to be having a problem with many of their AFPRs. Many of the older HSR fuel rail kits contained the wrong AFPR. Many of the new kits contain the right one, but the "right" one has many problems that you are having. Sounds like Holley has more then one problem to deal with.

 

i don't think i could have damaged both, but i guess anything is possible. trust me, at about $100+ a pop and the time it takes to install them, i was careful.

if only one had acted funny or the old AFPR had acted funny i would wonder, but with everything considered i believe it is the holley unit(s).

as for the check ball, again, all mine was new and worked fine with the old unit. can't help about the 'flat side'. try trixster, he is a stand up guy who helped me A LOT, even emailed me pages out of the manual!! (don't tell him i said nice things about him though)

anyone wanna finish my line yet? piece of _ _ _ _

 

I ran a Holley AFPR on my TPI setup for 2-3 years, no problems at all. 48psi w/ no vaccum every time I checked it.

Not sure if they changed the design after reading all this (turn the screw, tighten the nut) stuff...mine had an aluminum hat with serrated edges that you could adjust by hand.

Didn't do anything fancy installing it, just followed the directions and used a torque wrench tightening the Torx screws to spec.

 

you are correct about the little 'hat'. i really would like it if this thing work correctly. but it don't!!

i followed the direction for installing both of the units too but niether works as it should.

one question, did yours 'bleed' off pressure when you turned the key on?

 

When I'd turn the key to run (not start), the pressure would hit 48psi and stay there for the 2sec prime. When the pump shut off, pressure would drop to around 35psi and stay there for as long as I cared to stand there and stare at the gauge.

 

thanks kev

neither one of the holley i bought will do that (hold pressure). the old AFPR will, and again, that is why i suspect the holleys.

the worst thing is when i called holley the guy told me 'it must be designed to do that'. i now suspect he was even more clueless than i was. anyway, new one is on order, but NOT another holley.

when it is on i will post what the results are.