hi all


today i pick my iroc out of the garage!
i drive a few mile`s and smell some fuel in the car!

i park the car and take a look under the hood!

i see that the red piece of plastic/rubber was lost that you can see on the picture!
the fuel comming out of there!
i put a piece of windshieldwasser hose on it with a screw in it so it won`t leak anymore.

but it won`t work because i see the fuel is leaking on the top of the regulator!

what is happening here? broken gasket?

 

ooh and what is the function of that red piece of plastic/rubber?

 

The red thing is just a cap to cover the hole. It is designed to be connected to a vacuum source - for more fuel pressure adjustment with a blower/supercharger or something - nothing you need. And you don't have to have the cap on the vacuum fitting for any reason (other than to temp slow your leak at the moment).

If there's fuel leaking from the top, the diaphram inside is shot, and it'll need replaced. Mallory makes a replacement diaphram, but I have no idea on cost - check Summit or Jegs for a replacement. Take the adjuster out, then remove the 4 allen headed screws on the top, lift top off to replace. Bad diphram would cause a leak at that vacuum fitting.

 

hey thanks for the fast and great answer!
i hope i can fix it fast so i can drive it with the hot days here!!

dennis

 

One more thing I just thought of - just to CYA - If you are using the stock rubber fuel hoses ...

Check the return line and make sure there's no restriction in it. When I first installed mine, all I had was a 3/8 hose barb. The return line is a 5/16 hose. I shoved the barb in it anyway, wasn't easy, but I did it. Turns out the hose barb had cut the hose on the inside as I shoved/twisted that big barb in that smaller hose, causing a restriction. I never made my unit leak like yours is, but it did make my fuel pressure crazy high and fluctuate until I found the problem. I guess it's possible that enough of a restriction could make the diaphram leak or could prematurely ruin the diaphram.

 

i don`t use the stoch fuel hoses!

i have the stainles steel hoses from earl!

check the picture:

 

Very nice. I thought I saw AN fittings in the Mallory pic, but thought I'd throw it out there just in case.

 

Careful with that leaky fuel around the alternator. I hate regulators for this reason. I've had a cheaper one actually spray fuel at the alternator after the diaphragm tore. They have made me paranoid enough to put a fire extinguisher in my car just in case. I've trusted the mallory fpr but even so I'll rebuild it maybe every 8 months to a year.

 

thanks you to formula wolf:

but what is the reason that the diaphragm shot`s???
to much pressure from the original TPI pump?

so i must buy some for the future ! haha

dennis

 

How old is it? Could be age, defective at manufacture, etc. Could also be TPI pressure I guess - My car is an RS, so it was TBI and thus TBI pump=less pressure than TPI pump. Might ask Mallory tech on that, although I'm sure I've seen guys here use the TPI pump with them.

The diaphram is just a thin piece of rubber with a metal valve seat in the middle - I'm assuming the rubber gets torn or seperated from the metal.

 

i don`t know how old it is!maybe one year or two!

i just orded two of them. the extra one is for later if i need it again.

many thanks for your help.

 

A fuel pump does not create pressure, it creates flow, and this flow through a restriction gives you pressure. Just like a garden hose with your thumb over the end. A max dead head pressure is the pressure resulting from the amount of fuel the pump can cram into the line to the dead head.

The diaphragm should be fine to regulate your fuel pressure, maybe you just got a bad regulator. Maybe the bypass flow is excessive for this regulator. I don't know, I have never used a mallory regulator before.