I recently converted from TBI to carb, and i used a three port regulator for the return line. But everyday when i start the car it runs great for about 10 minutes then it dies, or if it sits and idles for about 3-5 minutes it will die. But when it does this i shut the key off for about 15 seconds then the fule pump primes again and it fires right up. I put a fuel pressure guage on it and it bobbles around every few seconds. Do i need to wire the in-tank fuel pump directly or is there like a relay that i need to wire to fix this problem, i imagine snflugus knows how to fix it cuz hes the one who wrote the tech article one the swap. or would it be easier to just install a holley red electric fuel pump? thanks for any input.

 

For a carbed car to die from lack of fuel, you would have to have no fuel pressure for a little while. Does the fuel pressure completely drop off to 0 when it dies?

 

Yes the fuel pressure guage reads zero for a little while then the fuel in the bowls runs out and it dies. but when its running the guage will stay steady on 6 pounds for a while then it will bobble around the it will get steady again, its sounds like the pump is trying to go out but i replaced it about 5 monthes ago so i know thats not the problem. Im curious if there is a relay or something that cutz off the power supply to the pump since there's no TBI.

 

There is a fuel pump relay but it either works or doesn't,it wont flicker like you say the gauge is doing.If the relay didnt work you wouldn't hear the pump come on at all,so we can rule that out.Make sure the gauge is good,I just had an inline Russel gauge on my Z that was doing this same thing and I thought my brand new Holley black pump was shot already.Turns out when I finally hooked up my Autometer fuel pressure gauge(in car with isolator)it stayed at a rock solid 6 psi,no fluctuation,the Russel gauge was shot.If the gauge is good,your pump is most likely on its way out,I know you say you just replaced it 5 months ago but parts can go bad in short amounts of time,I have gone thru that many times.If the gauge is good,its cheap enough just to throw a new relay on it if it makes you feel better,it is on the driver side of the firewall by the brake booster.From what you say it sounds like the pump to me.Hope this gives you some new things to look for.

 

theres a oil pressure sensor that also could be causing your problems....i think (dont quote me) that without proper oil pressure the fuel pump is kicked out.
I was having some troubles with this an by passed this sensor
It may be worth looking into, and someone else probably knows a bit more about this

good luck