New Accufab FPR Leaking!! Help

RED LS1

SENIOR MEMBER
Joined
Dec 31, 2001
Long story short.... I bought a good running 50,000 mile GN. I took everything off and cleaned and painted and replaced the usual items. Intake gasket, V/C gaskets, plugs, wires, O2 sensor, power plate, new 60lbs injectors, TT chip etc....

I replaced the stock FPR with a Accufab. It pours gas out of the O-ring at the rail. I tried both supplied O-rings and also 2 stock Injector o-rings and it didn't change a thing. I put the stock one back on and it is perfectly fine.

I drove the car around a little with the stock one on and it's now bucking under light boost. I'm not sure if it's because the Stock FPR is on or some other problem but what's some trick you guys are using to seal up these reg's. Some say the Hex nut is hitting the rail. Some say parts store O-rings seal it up. My friend just bought a new one last week and his is fine.

Need some ideas here
 
Are you getting good thread engagement? Aftermarket FPRs I've used (Accufab and Kirban) have thicker flanges than stock and if you have bolts (like I did) that have just enough depth for the stock FPR, then you need longer bolts to get good clamping.
 
Make sure you use some sort of grease when installing the reg as the o-ring can easily get pinched and distort....this will cause a leak.
 
I'm using the factory FPR bolts. They pull the reg into the rail tight and tighten up just fine. I couldn't imagine a longer bolt making it any tighter. I have lubed the o-ring properly every time. I was very careful not to have a pinch situation. I had the factory one back on 2 times now and neither time did anything pinch or not seat correctly so I must not be having an issue with that.
 
I called Accufab today. They know nothing of any problems of course. They told me to scotchbrite the fitting area because it likely has buildup and debree on it.The fitting area is 100% fresh machined surface with no pitting or anything. I tried to explain that to him and he told me it's there, I just can't see it. lol. The Vendor I bought it from in so many words said it has to go back to Accufab to be tested and rebuilt. They're in CA and I'm in PA so there's 2 weeks alone for shipping on a brand new part. I'm starting to wonder if the part of the fitting that screws into the reg is actually leaking.
 
Take a picture of the fuel rail port. The regulator has to fit tight and not be crooked. Ravege might be correct on the bolts. Are you sure it's leaking from there and not the return line fitting?
 
Aftermkt rails?
Leaking at the threads on the o'ring nipple?
Mine was new, wouldn't adj.. Full of chips, dirt, from the machining process.
 
I had an accufab leak around the rubber diaphragm between top and bottom. Screws holding the two parts together were loose.
 
And the rep was probably saying to clean inside the rail port, not the regulator. They do get nasty over the years and a dirty rail won't seal. Had that happen in the past too.
 
You might need to shim it so it doesn't go in too far and have the body of the regulator pinch the o-ring. Put a small washer in between the fuel and the regulator so you can pull it back enough just to get good engagement with the o-ring itself. The body of the regulator doesn't have to bottom out against the fuel rail.
 
Also the car shouldnt be acting up with either regulator as long as the pressure is set correctly. Might have another prob lurking somewhere.
 
I'm using the factory FPR bolts. They pull the reg into the rail tight and tighten up just fine. I couldn't imagine a longer bolt making it any tighter. I have lubed the o-ring properly every time. I was very careful not to have a pinch situation. I had the factory one back on 2 times now and neither time did anything pinch or not seat correctly so I must not be having an issue with that.

Make sure you don't lube the o-ring with an oil based lube. The o ring will swell and won't seat right. I use a silicon based lube.
 
Let me clear up some questions.

I've installed this regulator at least 10 different times. I've used a smidge of clear assembly grease on the O-ring like I have on Fuel Injectors my whole life without an issue. At one point on one of the many attempts I tried windex. I was talking to a 25 year Ford Tech I am friends with and that's what he's been using his whole life. What the heck, gave it a try.

The tech on the phone at Accufab was a nice a bubbly older fella. He didn't know a thing but he did ask about the bore of the fuel rail. I told him I examined with a fluorescent light and a pick and there's no flaking or debree anywhere in the whole. That's when he talked to another tech and the other tech mentioned cleaning the actual end on the FPR as it could have rust or pitting.

I really can't see how longer bolts would make it any tighter. It's getting 100% tight. I have the black GM O-ring on there because I tried both the supplied brown and they didn't work. The Black is .010 larger in diameter.

It's definitely the O-ring. The diaphragm is bone dry.

I understand this isn't the cause of the stumbling under boost. That's another problem for another day.

Lastly, I think Ttypewhite is correct. The Hex nut on the FPR drives straight into the rail opening. I can see it when I look real close while installed. I don't feel like spacing it would have a good seal at the o-ring though. I'm also confused as how others who have the same FPR don't have this problem.


I found a smaller O-ring and I added it to the area where the O-ring goes. It made the main O-ring nice and tight and up front stationary instead of loose and moving up and down with tons of play. Almost as how the factory one has the grey spacer and the o-ring stays firm and tight. It didn't work out though as it just mangled up in there and was worse than ever before.

I ordered another regulator from Kirban today and I will have it tomorrow. I want to rule out this regulator altogether.
 
You might need to shim it so it doesn't go in too far and have the body of the regulator pinch the o-ring. Put a small washer in between the fuel and the regulator so you can pull it back enough just to get good engagement with the o-ring itself. The body of the regulator doesn't have to bottom out against the fuel rail.

I think this is likely the issue. You could also mask off the end with the o-ring so no metal shavings get in and modify the hex head round with a Dremel. I bet that hex head isn't letting it seat properly. You could take the o ring off and try to set it into the fuel rail to see if this is the issue. Obviously you can't use it like that but that may let you see the issue you're having.


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The nipple that the o'ring sits on has a flange on it, so it will not pull too far into the rail. {Stock rail}. Once the o'ring is past the flare on the rail bore, it is sealed. Key here is "past the flare on the rail bore". If the bolts are pulled down evenly, the reg should not cock in the bore.
The brown vs the blk o'ring is not a concern. Both are rated for gasoline fuel.
My experience is the brown tended to harden, while the blk did not. I use only the black, on inj cleaning jobs. My supplier reports that the brown composition is now much more reliable.
If this is an alum rail: I've seen the bores drilled and tool marks cause leaks. {Chinese junk}.
The Acufab reg uses a STD EV1 inj o'ring.
 
I don't have any interest in grinding down the hex points. Maybe down the road if I can't return it and i'm stuck with it. But for now I think that's ridiculous. I know i'm evenly and carefully tightening the bolts. I can see maybe the first 1 or two times I've installed it, but the next 8 times I was paying careful attention to everything. I guess we'll see if it's me or not when the Kirban one gets here. That will be an interesting conversation to have with Accufab. "Hey, Kirban one sealed right up."
 
Got the Kirban one on and it sealed right up no problems. Dry as a bone.

On another note. My stumbling under boost issue did not change. I can't find my TT instructions to see what the FP should be at. I have it at 45 line off and only drops to 39-40 psi with the line on.
 
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