agrabau

Sharif, actually not too much in our case. My impression is that high power is no problem as less fuel has to return to the pump. More fuel is being consumed by the the engine/injector train and therefore a smaller diameter return is sufficient. In Mike's case (and I don't think that this is the main problem, only something that can be improved upon) the engine is making what? 400 crank and -4 may not be enough to drop the return pressure.

I'm sure AA will take care of the FPR but now I'd like to know why the pressure is high and also about the internal whereabouts/layout of the pump housing so we can figure this out.

Thanks guys.

Badmonkey

iTrader: (9)

Alex,
I put together my own return system and i used 3/8" aluminum fuel line from the engine bay to the bottom of the tank. I then used a 1 ft section of -4 linr to the -4 bulkhead return fitting. The fuel line is very inexpensive and easy to work with. There are really not that many bends to put in the line and it clamped into the stock fuel line holders, nicely. Just giving you an idea of what I did.

As far as the cause of the rupture, who knows, I wonder if the siphon jet got clogged or blocked, causing high pressure. The siphon jet is nothing more than a small plastic elbow with a hole in it. It is located on the bottom of the fuel pump assembly. The return fuel is split between this siphon jet and swirl jet. The fuel is sucked from the driver's side of the fuel tank with the pressure differential created by the hole. Some return fuel systems, that are running the Walbro, need the hole enlarged in order to allow more fuel through. I had to enlarge mine a little bit because my fuel pressure would not go lower than 58-60 psi. The recommended size is about .065-.070 inches.

If the o-ring is already disintegrating, it makes me wonder why. I am unaware of the proper size, but I am sure that you can get the info from AAM or Sharif. I definitely would change it out.

Sharif@Forged

iTrader: (92)

Oh, I see. In terms of return, we are able to dial down the FPR to 35psi on at least two customer's cars with the same system. A new replacement FPR will solve your issue, and you will have no trouble setting your fuel pressure at the proper level. Is there something I missed in your question, or was the main problem here, just the high fuel pressure?

I regards to the siphon kit, the return line is fed through a 90 degree fitting, through the fuel pump assembly, and a hose runs to the replacement FPR plug. Can you clarify what question you had in terms of siphon?

Badmonkey

iTrader: (9)

The fuel pump housing is located behind the passenger seat under the plastic "floor" of the storage area. There are several screws around the top. The whole assembly then pulls out. Be careful, because the fuel level rod is also attached to this assembly. The siphon jet is located on the very bottom and, using needle nose pliers, will pop off. Make sure that you do not snap this piece, as I understand it, you cannot get the piece by itself. You would need to buy the entire fuel pump assembly.

agrabau

Badmonkey, is it the yellow plastic tab? I think we're getting close to a solution.

Sharif, I installed the kit so I'm familiar with the fitting arrangement. I'm (I guess) trying to learn the functionality of the internals like the what Badmonkey is talking about. So.. the stock FPR returns fuel upward into a cylindrical container which is the syphon pump housing?

A replacement FPR will not solve this problem on it's own as demonstrated by my installing the SARD FPR and finding the same results. That's not to say that we don't need a replacement though, as this one is broken.

Thanks guys!

A

Badmonkey

iTrader: (9)

Yes, it is a yellowish 90 degree elbow, which attaches to a line.

agrabau

PS- I'm going to call Greene rubber or Parker O ring and try to source a nitrile (buna-N) o ring for this application.

agrabau

If that were blocked it would result in a high pressure situation?

What if the O ring on the stock FPR replacement were leaking what would result? Low pressure right, it would be an equalization of pressure with the tank right?

Badmonkey

iTrader: (9)

I think that if the o-ring failed and was leaking, you would not notice too much of a difference, pressure-wise. If the swirl jet is large enough to not restrict the return fuel that it has to deal with, then the failed o-ring would just be another port for the fuel to go. The returning fuel should remain at the pressure set by the FPR, give or take a slight change, if the entire o-ring assembly failed. You may lose your siphon capability, which would result in running out of gas early. That is the problem that I had. I would run out of fuel with 1/4 tank left.

leemik

iTrader: (2)

Yo Alex, thanks for working so hard on this for me.. I know I bug you a lot and it's much appreciated.. I wish all garages were like yours!!

Here is a pic of the busted Aeromotive FPR:

35ounces

iTrader: (5)

I bet I bugged him more than you! +1 DSG rocks.

leemik

iTrader: (2)

UPDATE: I got the new FPR--Thanks to Dave from AAM for the very quick response and excellent customer service.. but this new one won't go lower than 52psi at idle with the vacuum hose off.. The "loaner" SARD FPR however works fine and dials down to 40psi with no problem.... So I'm currently still running with the SARD until I can buy my own..I've given up on AAM's FPR..

and I've been saying in previous posts that the one in the AAM kit is an Aeromotive FPR.. well the one I got looks like an Aeromotive FPR in design but is probably a knock off?? Mine has a silver top.. i noticed earlier kits had red tops and actually say "Aeromotive?"

Another observation is that I haven't had any warm start issues running with the SARD

--mike

35ounces

iTrader: (5)

that sucks! Just buy a SARD I guess.

Anyone know which one comes with Phunks fuel system?