FPR doesn't... regulate pressure!
 

Hey Guys,

So I finally got a round to it. No, not a Round Tuit (though I *do* have one of those), I actually got around to installing the replacement for the Mallory Comp70 I blew (another Mallory Comp70) AND my new 1-10psi Fuel Pressure Guage!

The problem now is that no matter what I do, I can't bring the pressure down! The Mallory puts out 6psi, I know that, which is why I bought a Holley "1-4psi" fuel pressure regulator. Well I installed my guage in-line between the regulator and the carb to get an accurate reading of what kind of pressure the carb was seeing, and it gets 5psi!

So alright, I loosen the lock nut on the regulator, and turn it all the way in. Still 5psi. So I then turn it all the way *out*, still 5psi. I turn it freely from one extreme to the other and the fuel pressure does not change one bit!

So I figured that maybe the check valve in the return line was providing too much restriction. I replaced the return line with a piece of 5/16" fuel hose, no restrictor and tried again. Same difference!

So I tried a few things to make sure the gauge was reading alright. Pinching the line made the pressure drop as I cut off flow before the guage. Bending the line let the guage drop down to zero. And "pulsing" the line with my fingers gave a 1-2psi "bounce" in the guage, perfect.

So I'm guessing I'll have to get a new regulator to make this work! I'm thinking about a Mallory return-style regulator, and then capping the return on my carb. That should let me regulate the pressure down to 2.5-3psi which the carb likes, and return any excess back to the tank through the regulator.

I took a short video of it, but the quality royally sucks, and google videos hasn't "verified" it yet. I'll take a better one tomorrow and post it. I just wanted to get some feedback.

So did anyone else with the guage find any odd things about your pressure regulators? Does anyone with a holley 1-4psi have this same problem?

Jon

mallory came with 2 styles. I bet what you have is the one with stiff spring for high pressure; Just like the one I bought when I had a MSD F/I F/P.

Get a holley regulator. less headache.

I have the Holley FPR too
 

Jon,

I have the Holley 1-4 FPR, the "new" 1-10 psi gauge with dry-disconnect, but I have a Carter 7lb fuel pump. We were able to dial in 2.5-3.0 (and anywhere in between) with amazing accuracy. However, I did notice the FPR seemed "stuck" at 3.5 but with a little screw-it-in screw-it-out a few times at the adjustment it finally freed up and everything seems to be working great.

This is not the problem but did you notice the gauge sticker on the side said to tighten the nut on top of the gauge, too? (the blowout assy.)

DD

I have a holley regulator... and it's my headache right now. Looking at the dissasembly diagram, I don't think my Mallory has any springs in it... *looks confused*


No, I didn't touch the nut on the top of the guage... hmm.. but you say that's not the problem?



Anyone else have any ideas? I'm thinkin' it's the regulator at this point, but I'd be reluctant to buy another holley because this one isn't working as advertised.

Jon

Ah, wacky I think I get what you were trying to say.

Holley makes two FPRs. 1-4psi and 4.5-9psi

And the forkwad who got my guage from the storage room probably picked up the wrong one, so I have an FPR that won't regulate it any lower than 4.5psi.

Does that sound right?

Jon

Sounds like a very likely posibility to me. I am not sure if there are part numbers on the FPR itself but should be on the box if you still have it.

You can just replace the spring in the FPR if you have the wrong one right now. Also, turning in = higher pressure, while turning out = lower pressure on the Holley FPR.

One more question
 

Jon,

I can't really tell from the picture so I'll just ask and I'm not trying to insult you. It kind of looks like you put the "snubber" on the quick-disconnect piece that stays mounted in the car. If so, the "snubber" HAS to screw directly to the gauge. That could be the problem.

If not, sorry to question your setup, and I would suspect a faulty FPR.

And in case you discarded the sticker on the gauge, it says:

" AFTER INSTALLATION
If liquid filled and range 0-300PSI and below
remove shipping gasket from blowout assembly to
allow case to vent to atmosphere.

If gauge is not liquid filled shipping gasket should not
be removed and blowout assembly should be tightened
with a wrench to seal gauge from atmosphere."

Added: The snubber is that little threaded "filter thingie" and "it saves your gauge in a pressure spike".

DD

I omitted the snubber completely. I figure with a 6psi fuel pump, and the guage rated to 130% of guage range, I don't think I could spike to more than 13psi no matter what I did. Especially with the guage being after the 1-4psi regulator, I'd have to somehow push more than three times the regulator's max pressure through just to hit the limit of the guage (and twice the max pressure of my pump!)

No part number on the regulator, and it amazingly enough didn't come in a box. It just came shrinkwrapped to its instructions. My pump came in a box, but that doesn't help.

Where can you get the other springs?

I'll go tighten the blowout assembly on my guage too, even though that shouldn't make a difference.

Jon

i dont think theres yo much to the fpr just some in and outs some diaphrams

i got the wrong one the 4.5-9psi but if you pretty much take the adjuster out its round about 2-3psi

you should be able to buy the springs from any autoparts store(probaly order)usally comes with 2 springs the high pressure and the low pressure 1-4 which is a red spring...

hope that helps
all the best

i installed the 7lb carter and holley 1-4 as well this weekend. i had a problem when i first installed showing 5lbs, but im sure it was the gauge. things straightened up and we dialed in 2.5lbs easily. you realize that a 1-10psi guage cant be "that" accurate at that low a pressure, right?

The regulator he is using is highly accurate.

Jon,

You can get the rebuild kit for about $5.00 US. The part number you are looking for is: 12-807

It will contain both springs the best I can tell. I can get it for you but by the time you through in shipping it would cost as much as the regulator :(

-billy

shrink wrap only???

where did you buy the regualtor from?

I got it from a local parts store that's usually pretty reliable. I got the pump there too and it was in full box form.

I'll just get another regulator. As long as it comes out to less than $50 and it actually does what it's supposed to do, I won't wince at buying it.

I re-tested it again today and it was 4psi, but the fuel was forcing its way past the needle and seat and slowly leaking into the barrels!

Looks like the car isn't drivable until I get the reg fixed. Or at least it will be flooding and bogging alot.... like last year with the first mallory. I was wondering why it acted weird, now I know.

Nothing beats having accurate instrumentation. It's like opening a door and seeing the light, I finally know what's been happening with the high pressure pump, and why the car hasn't been performing optimally.

And I *know* the guage is accurate. Despite the fact that it's 1-10psi, it's not a 3-2-3 guage like the crappy parts store ones. It's an industrial piece, rated accurate to a crazy good accuracy which I can't remember (a quarter of a percent of guage range IIRC).

Jon

Most of the online parts houses carry them, along with some of the auto parts stores and speed shops. 24-25 bucks is the going rate. There are 4 versions of them. 1-4 and 4-1/2-9 psi, in a choice of chrome or not. They all start with the same casting, the springs/diaphrams and finsh vary.

Jon, I need a stack of those Round Tuit medallions. I have more unfinshed/ongoing projects than $100T2 does. :wallbash:

i bought mine at Summit. i'm not sur what it's like to ship it to Canada, but you'll get the right part. however, it would seem that the proper thing for them to do would be to take it back, since it's not your fault that they gave you the wrong one. you did specify what you needed so ...

if you want to me to go dig up the part number for you, i can. that way you've done most of the work for them and hopefully will get the right thing this time.

good luck.

Yeah, I won't return it because I have had it installed for almost two years now. Yes they messed up, but I didn't catch it fast enough and for 25 bucks it's not worth the effort.

I'll get the part number from summit and take the printout to the local speed shop. When I buy it I'll make sure they know that if I install it and it won't regulate the pressure I'm bringing it back.

I'll let you guys know how it goes. With any luck I'll have one by the end of the week.

Jon

2 years, eh? bummer ...

well, good luck with it. i'm sure it will work. i bought the 4.5 to 9 psi regulator, myself and found out the hard way that it was wrong and i was kind of in the same boat, too - lots of time passed between install and my actual installation. however, i gave mine to my brother (for his Holley 650) and bought the right one for myself (and my old Dell).

you'll be happy when you get it, i almost promise! :D

hope you get it worked out

Update:

Yup, it was the wrong FPR.

Bought "another" Holley 1-4psi FPR and swapped it in. Now my fuel pressure is *exactly* 3psi, right where I want it. Not a tenth more or less!

Jon

isnt four psi low, dont u want higher??