Besides installing a three port afpr is there anything else I need to know about....
Thread Starter
Junior Member
Joined: Nov 1999
Posts: 79
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From: Monroe,LA,
Besides installing a three port afpr is there anything else I need to know about....
fuel delivery when switching to carb. I heard that the fuel pump is controlled by the computer, is this true. If this is true what will I have to do to make it cut on with the key? any help would be great.
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87'IROC-Z 350 TPI
Ported Plenum,Hypertech Air Foil,Ram Air kit,SLP headers,AFPR,80series flowmaster and MAF screens removed.
14.61@94mph(90+ degree weather)
------------------
87'IROC-Z 350 TPI
Ported Plenum,Hypertech Air Foil,Ram Air kit,SLP headers,AFPR,80series flowmaster and MAF screens removed.
14.61@94mph(90+ degree weather)
Member
Joined: Feb 2000
Posts: 195
Likes: 0
From: P.Pines, FL, USA
Yes, the ECM controls the fuel pump (it turns on the relay). If you remove the computer you will need to do some minor rewiring, you will need to hook up the relay "trigger' to the ignition switch.
One problem I had when I went from MPFI (2.8) to carb (350 crate motor), was, even thought I used a 3 port return style regulator (Mallory) I couldn't get the pressure below 30PSI without having the pump "surge".
I went the expensive (VERY VERY EXPENSIVE) route and had a sump welded on the stock tank and I'm running a Holley BLUE fuel pump through braided stainless line (-08).
The cheaper (and MUCH easier) way to do it would be to still use a 3 port return (you might be able to get away with a "dead head" carb regulator) but to replace the EFI in-tank pump with a TBI intanke unti, EFI- 40#s, TBI- 12#-15#s.
I've got a spare Mallory "dead head" style regulator in my tool box that I can let you borrow (we can work out some kind of deal) if you like. And you should be able to get a TBI pump pretty cheap from the local auto parts store.
What are you doing with your TPI setup?
I'm looking to swap back to TPI within the next month.
If you want to make a deal E-mail me @ J812MANY@aol.com
Good Luck,
John
One problem I had when I went from MPFI (2.8) to carb (350 crate motor), was, even thought I used a 3 port return style regulator (Mallory) I couldn't get the pressure below 30PSI without having the pump "surge".
I went the expensive (VERY VERY EXPENSIVE) route and had a sump welded on the stock tank and I'm running a Holley BLUE fuel pump through braided stainless line (-08).
The cheaper (and MUCH easier) way to do it would be to still use a 3 port return (you might be able to get away with a "dead head" carb regulator) but to replace the EFI in-tank pump with a TBI intanke unti, EFI- 40#s, TBI- 12#-15#s.
I've got a spare Mallory "dead head" style regulator in my tool box that I can let you borrow (we can work out some kind of deal) if you like. And you should be able to get a TBI pump pretty cheap from the local auto parts store.
What are you doing with your TPI setup?
I'm looking to swap back to TPI within the next month.
If you want to make a deal E-mail me @ J812MANY@aol.com
Good Luck,
John
Thread Starter
Junior Member
Joined: Nov 1999
Posts: 79
Likes: 0
From: Monroe,LA,
So I am going to have to drop that damn tank again 
? There has to be a way around that isn't there? If I am going to have to drop the tank I will just make it where I can use a mechanical fuel pump.
I plan on keeping the TPI just in case we ever get emmissions down here. I do have an extra ported plenum, intake and runners though. They aren't in the best shape, but they could be cleaned up.
? There has to be a way around that isn't there? If I am going to have to drop the tank I will just make it where I can use a mechanical fuel pump. I plan on keeping the TPI just in case we ever get emmissions down here. I do have an extra ported plenum, intake and runners though. They aren't in the best shape, but they could be cleaned up.
Member
Joined: Jul 1999
Posts: 205
Likes: 0
From: Norman, OK, USA
Southern,
I made the swap from tbi to carb a few weeks ago. Of course I have a 92 RS, but left the harness in, removed the ecm and the fuel pump in the tank still works fine. I did install a mallory regulator tho. Fuel pump pressure, according the mallory can be regulated from 3 psi up to 50 psi, with a change of internal spring. I used the exsisting fuel lines with some fabrication for the carb and regulator.
I made the swap from tbi to carb a few weeks ago. Of course I have a 92 RS, but left the harness in, removed the ecm and the fuel pump in the tank still works fine. I did install a mallory regulator tho. Fuel pump pressure, according the mallory can be regulated from 3 psi up to 50 psi, with a change of internal spring. I used the exsisting fuel lines with some fabrication for the carb and regulator.
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