While doing my injector cups, I opted to also do a HPOP and fuel bowl re-seal. I have followed the instructions to the letter.

Now in the process of getting the truck ready for restarting, fuel is spraying out of my fuel bowl; around the seal at the top of the cap, out of the seals on the drain valve, and it looks like a little bit out of the sensor openings.

I couldn't have screwed ALL of those things up, I am suspecting the fuel pressure regulator isn't behaving as it should, and I am getting way too much pressure. I was very VERY careful when re-assembling the FPR that I didn't get the spring hooked on a housing rib, and I have now disassembled and inspected it twice. Everything looks right. I even disconnected the line that attaches to the output of the FPR, to make sure it wasn't blocked somehow. Fuel still sprayed out around the lid seal of the bowl, but nothing came out of the FPR outlet.

I would imagine that if the FPR poppet seal leaked, you'd get LESS pressure, wouldn't that be the case? And I have reached in from inside the fuel bowl and pressed the poppet outward, so I know it does move. It doesn't seem to be binding.

I'm not averse to buying new poppet parts, and perhaps a billet housing, I'd just like to know what, if anything, I messed up.

Also, I notice that there appears to be a tiny little orifice at the very bottom of the poppet valve (within the spring cavity). I can't see daylight through it, should I be able to? I can see daylight through the other two orifices in the cavity that the poppet seat goes into.

This device seemed to be working properly before I serviced it. Murphy's Law.

Any help or suggestions would be greatly appreciated.

 

Could I possibly have the beveled seal in backwards? Does the bevel go towards the seat, or towards the poppet?

 

Only thing I can offer is...











Check the fuel pressure...

 

I turned the beveled seal back around so that the beveled surface is facing back towards the valve seat, still leaks.

 

I had a high fuel pressure problem. My fuel pump would cut out at 110 psi and then come back on when pressure dropped to around 45 psi, so it constantly cycled on and off.

At 110 psi, none of the seals in my fuel bowl leaked. I would suggest you try a new o-ring for the lid, remove the other seals that are leaking and make sure the surfaces they sit on are clean and no pieces of rubber or trash are stuck anywhere, and try again.

Checking fuel pressure would put your mind at ease, so do that if you've got the parts available, but I don't think that's the cause of the leaks.

 

If you had the return line off and nothing came out for sure something is wrong with the fpr.

Did you use the stock spring? Are you sure you have the poppet facing the bowl and not the cap? (spring on the cap side poppet on the bowl side).

 

Like this:

 

I just had the fuel bowl off of the truck and completely went through it, all new o-rings. I was super careful with all of the cleaning and installation. The top seal I did not replace, but it was working before I took the bowl off of the truck. The fact that it is leaking in three different places seems to suggest the pressure must be way high. I can't imagine I screwed all of those things up!


That was my conclusion too. The last couple of tests I had the return line off (to also rule out a clogged return line).


I did use the stock spring. I am 100% positive that it was not hug up on the inside ribs, and yes, the parts are oriented as you described. I am coming to the conclusion that the poppet has got to be just hanging up in the guide for some reason.

I do still wonder about the little tiny hole at the end of the poppet. I can see the hole on the inside and on the outside of the poppet, but I could not see daylight through it. I will look at it under more magnification. It's got to have a function, and I wonder if I may have clogged it during the cleaning process.

If all else fails, I will probably just replace these parts. I may do the billet housing upgrade in the process. Or, what about the Frx? Does it replace the housing?

Thanks for all of your help everyone.

.

 

think the "hole" in the poppett is nothing more than a dimple during manufacturing. If there was a hole through it, you wouldn't have any back pressure.

 

Could be a centering mark from machining, I guess. There are two distinct holes in the flange under the seal though, they must perform some function.

 

I saw the holes when I had mine apart as well. I believe they may have been put there to cut down on "chatter/banging" of the valve partially because of the pulse from the pump. Either way it is good to make sure ALL passages, holes, journals, lines, etc. is completely clean when doing fuel and oil "stuff" work.



Are the leaks just pouring fuel? Maybe the leaks you have are simply leaks and are outflowing the pump. Like others mentioned a fuel pressure check should be done.

 

When I turn the key off, and the spraying subsides, and I take the cover off of the bowl, there is still fuel in the bowl. In other words, two of the leak points (the drain valve and the sensor) are below the level of the fuel, but they stop leaking and the bowl remains full; those points aren't leaking when they are not under pressure. And, these are all-new seals. I went through the entire bowl and did everything.

I might have suspected just the top cover gasket, if the other points weren't spraying also. And it's not just dribbling out, the fuel bowl looks like a fountain when the key is on.

I don't know that I have the hardware available to do a fuel pressure test. Is there a quick and dirty way?

I suppose it's possible that back when I had the fuel in coolant problem that started all of this (described in another thread), I could have had a high-pressure fuel situation that developed and made it more evident. The cracks in my injector cups were quite small. However, the quantity of fuel getting sprayed now is huge, I think I would have noticed that back then. Then again, the engine was running, it's not right now.

 

Like Joe said, you need to check the fuel pressure. I use an old oil press guage that I plumb into the pre filter port on the fuel bowl. You can get one at any parts store for cheap. You will have to get an adapter though. I got one from Clay at Riff Raff. You can leave it (adapter) there with an npt plug for future use. Or install a permenant gauge, very handy.

 

There is a hole in the poppet. I am not sure what it's for but if you hold it up to a light bulb you will see some light come through the orifice. I was able to blow air through the hole in one direction but not the other so I suspect it may be a check valve of some kind.

 

Thanks Jim. I will scrounge around and see if I can come up with a gauge.

Yep, thanks. I brought the poppet into work and looked at it with our microscope, there is indeed a hole, and it was completely plugged. I soaked it in some MEK for a half-hour, and then was able to clear it with a tiny wire. It looks like the hole is a little over ten thousandths diameter. Certainly not enough to reduce the pressure significantly on its own.

It might be there to allow the pressure to bleed back down after you shut off the engine, but I suspect there might be a more subtle function. I've seen some pretty tricky regulator schemes, I wouldn't be surprised if this was some sort of a pilot hole to allow a little pressure through to perform some function. The fact that there are two holes up on the poppet flange adds to the mystery. Engineers and manufacturers don't just add holes to machined parts unless they actually fulfill a purpose.

I probably caused the tiny hole to become plugged when I was cleaning all of the parts. Now that I have it cleared, I'll take it back out and install it on the truck and see if I still have a "fuel fountain". Fingers crossed.