Best fuel pump/carb option
- Thread starter MARCH374
- Start date
I think that system can be used either way (with or without a return). If the fuel tank vent (ie: charcoal canister) is not venting, it won't matter if his FI has a return line or not. You still end up sucking from a closed system until the fuel tank ends up in a vacuum (think of drinking from a plastic soda bottle, with your lips surrounding the opening).
Now that is if his fuel tank vent is the cause of the problem - which is not yet known.
It sounds like a fuel tank vent problem, though, but might be the pump itself. Electric fuel pumps don't like sucking.
Correction. We got a reply before I had hit enter.
if no change with gas cap is off, then it is not a vent problem.
I don't see the fuel return (or lack thereof) will just now start a problem (unless it has been doing this for a long time).
A weak (or failing) fuel pump, a restriction in the fuel line (line got bent or kinked from something getting kicked up from road), stopped up fuel filter or ignition system sound like the most likely causes to me. If it is ignition system, then installing a carburetor will not fix the problem.
I wish he was close by. I have a spare ignition system that could be used as a quick test.
Another thing I would test is to rent (or buy) a fuel pressure tester and see what, exactly, your fuel pressure reading is when car is acting up. Fuel injection requires a min level of fuel pressure or it will act up if the pressure drops below that threshold.
BudW
How old is your fuel filter?
I would get car into the air (safely) and follow the fuel lines from start to finish, to check for any kinks or other damage. There are three hidden fuel hoses under the passenger side firewall (under car). I wonder if one of those hoses has gone bad (ie: stopping or restricting fuel flow).
If filter is not that old and fuel lines/hoses are good, and sense fuel pressure doesn't change then my next guess would be the FI system is working fine and finger now points to the ignition system.
Are you using a MSD ignition coil or stock coil?
BudW
I would get car into the air (safely) and follow the fuel lines from start to finish, to check for any kinks or other damage. There are three hidden fuel hoses under the passenger side firewall (under car). I wonder if one of those hoses has gone bad (ie: stopping or restricting fuel flow).
If filter is not that old and fuel lines/hoses are good, and sense fuel pressure doesn't change then my next guess would be the FI system is working fine and finger now points to the ignition system.
Are you using a MSD ignition coil or stock coil?
BudW
jasperjacko
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pick up clogging with junk in the tank?
Will put that on my list to check. Thanks
Do you have a pic of the fuel pump? I have used a powerjection iii (I know shock and horror but it worked for me) and switched to a Holley Sniper recently.
I would like to see how the fuel pump is wired up. I would be inclined to run a switched 12 volts straight to the fuel pump and make sure you are not fighting some strange fuel on demand issue. The other thing I would check is to get the car in air safely and put a multi-meter to the hot line to the fuel pump. Have some start it and watch and see if you are getting a voltage drop or loss after the pressure goes away. If power is controlled by the Atomic it may be cutting power to pump.
The fact that after a quick cycle of the ignition doesn't bring the pressure back really points to the power to fuel pump or fuel pump. Electric fuel pumps almost never lose the ability to pump unless they are clogged. Invariably what happens is the one way valve that holds pressure in the line between starts goes bad.
If you really want a carb the street demon is one of the best for just general driving I have ever run across. The summit carb is pretty solid too.
We might drive you a little nuts with suggestions
but there are a bunch of people on here with years of experience and most of us are happy to try and help.
I would like to see how the fuel pump is wired up. I would be inclined to run a switched 12 volts straight to the fuel pump and make sure you are not fighting some strange fuel on demand issue. The other thing I would check is to get the car in air safely and put a multi-meter to the hot line to the fuel pump. Have some start it and watch and see if you are getting a voltage drop or loss after the pressure goes away. If power is controlled by the Atomic it may be cutting power to pump.
The fact that after a quick cycle of the ignition doesn't bring the pressure back really points to the power to fuel pump or fuel pump. Electric fuel pumps almost never lose the ability to pump unless they are clogged. Invariably what happens is the one way valve that holds pressure in the line between starts goes bad.
If you really want a carb the street demon is one of the best for just general driving I have ever run across. The summit carb is pretty solid too.
We might drive you a little nuts with suggestions
but there are a bunch of people on here with years of experience and most of us are happy to try and help.Thanks, Just had a chance to look at car again today. I took apart cap,rotor and mag p.u assy( looks toasted) I found that the P.U ASSY is wire to throttle body. Hopefully thisDo you have a pic of the fuel pump? I have used a powerjection iii (I know shock and horror but it worked for me) and switched to a Holley Sniper recently.
I would like to see how the fuel pump is wired up. I would be inclined to run a switched 12 volts straight to the fuel pump and make sure you are not fighting some strange fuel on demand issue. The other thing I would check is to get the car in air safely and put a multi-meter to the hot line to the fuel pump. Have some start it and watch and see if you are getting a voltage drop or loss after the pressure goes away. If power is controlled by the Atomic it may be cutting power to pump.
The fact that after a quick cycle of the ignition doesn't bring the pressure back really points to the power to fuel pump or fuel pump. Electric fuel pumps almost never lose the ability to pump unless they are clogged. Invariably what happens is the one way valve that holds pressure in the line between starts goes bad.
If you really want a carb the street demon is one of the best for just general driving I have ever run across. The summit carb is pretty solid too.
We might drive you a little nuts with suggestions
is problem, i just ordered replacement parts.
I cant figure the fuel pump wiring because i thought that might be the problem also. When pump wasnt going on
when i turn the key i took a test light to it. Nothing no power so i had someone crank engine because MSD said pump gets signal from Power Module. Still no power, i
got new pump and tested old pump it didnt work. Put new pump in and it worked. Still dont understand WHY ????.
Its beyond my skill set. Hopefully the new P.U Assy fixes the problem. If no good i am getting the Street Demon. Keep you posted. Thanks again.
LSM360
Well-Known Member
Because it was mentioned, I have an Edlebrock Air Gap manifold with stock 4 barrel air cleaner on my '89 AHB with FiTech and there's hood clearance.
