Fuel Delivery: TPI to Carb Conversion

[88WS-6]

I did not do this swap, I am merely dealing with the aftermath. First step is to figure out what exactly was done, then I will move into the problem solving phase. If possible, I'd like to just use the stock in-tank pump with a Mallory 4309 AFPR and hook everything up correctly.

Pictures of the current set-up in the engine bay:








A few pictures of a successful Mallory 4309 AFPR install (thanks to LilJayV10 at thirdgen.org for the pics)








A few things to note:
The previous owner said he disconnected the stock TPI in-tank pump, but it is still there. He also installed a Holley (blue?) pump just before the rear axle (i'll get some pics this afternoon). Phil's eagle eye spotted a mechanical pump on the block so basically... WTF.

Mallory 4309 install thread here:

http://www.thirdgen.org/techboard/ca...installed.html




I'll take some more pics under the hood when I get home as well.

~Matt

[BonzoHansen]

why not just use a mechanical f/p for the carb? Simple, reliable, cheap.

[88WS-6]

Well I may go that route, but apparently it was attempted already. It may be running off that now, although I just found out it was even there. Before I think about the solution I'm going to try to figure out what is working/not working as it sits.

Also, I tend to do things backwards and in ways that cost more money in the end for no particular reason, so try to work with me here.

[sweetbmxrider]

Well you want it to be reliable since it was cutting out on the highway, the car has 3 fuel pumps (I should look into this), and who doesn't like inexpensive?

Mechanical fuel pump or hit your head with a hammer until it makes sense.

[BonzoHansen]

Originally Posted by 88WS-6

Before I think about the solution I'm going to try to figure out what is working/not working as it sits.

Good call. I think you might need to determine where you actually stand now. Then go from there. But that feed line sure looks like it heads to the pump on the block.



Based on what I have read so far, like those electric fans on a manual switch that HVAC setup, and your comments on the fuel system, I might make WAG that you may have a lot of room for improvement/optimization by simply backing up and doing somethings right, nodding towards the KISS principle when possible. Don't over complicate a simple setup.

Just my $0.02. BTDT, lived to tell the tale.

[WildBillyT]

Originally Posted by BonzoHansen

Good call. I think you might need to determine where you actually stand now. Then go from there. But that feed line sure looks like it heads to the pump on the block.



Based on what I have read so far, like those electric fans on a manual switch that HVAC setup, and your comments on the fuel system, I might make WAG that you may have a lot of room for improvement/optimization by simply backing up and doing somethings right, nodding towards the KISS principle when possible. Don't over complicate a simple setup.

Just my $0.02. BTDT, lived to tell the tale.

Yup. I run a mech pump on my Nova for that reason. Much less to fail, and it's not a race car so what's a few hp. No regulator required.

Also, regardless of setup you should have a fuel filter as the last thing in the line before the carb. And definetly get a double throttle return spring.

[BonzoHansen]

and I wouldn't blindly put your running issues all on fuel. A lot of "fuel" problems are ignition problems.

[88WS-6]

Originally Posted by sweetbmxrider

the car has 3 fuel pumps (I should look into this)

Shouldn't it run 3 times more awesome then?

[88WS-6]

Originally Posted by BonzoHansen

and I wouldn't blindly put your running issues all on fuel. A lot of "fuel" problems are ignition problems.

From what I can tell it's a brand new Accel vaccum HEI distributor, cap and rotor. He said plugs and wires too, but we'll see...


Oh and the Crane ignition box but I'm not sure if that was used when he installed it. I think the dryer hose on the heater box underneath it was used though.

[BonzoHansen]

ha ha ha i had a world of trouble with an accell dizzy I had to buy in a pinch. just last spring

add: oh yeah, my problems sounded kind of like yours, acted up after it got hot.

[88WS-6]

This should work well:
http://www.summitracing.com/parts/CRT-M6626/

That pump has a regulator inside of it.

[88WS-6]

I was also just reading that, at least in 87, the LG4 had an electric in-tank pump and a mechanical pump on the block. I'll try to confirm that, but WTF?

It is apparently also better to keep the in-tank electric pump and use a regulator at the carb so that you can return the excess fuel and not have a "dead head" pump. Does that make sense?

[BonzoHansen]

the first one is a basic stock replacement. might be the same one I have in the 77. note that one has a return line.

some 3rd gens did get some kind of helper pump IIRC but I know not why.

[//<86TA>\\]

the helper pump was for vapor lock issues i believe.

if the car is to stay carbed, the tank needs to be removed, whatever pump setup is in there needs to be removed and bypassed. After that, a mechanical pump will be fine, so long as the fuel lines are well insulated, especially if the mechanical pump has no return line. Or keep the ghetto electric pump and ditch the mechanical pump, but you still should have a return line.

You should also look into what happened to the fuel hardlines. They should be on the driverside, they are not visible in the pics, so where are they? Hopefully there is not 15' of rubber hose running under the car.

[The Fixer]

Are you sure the car was an LB9 car to start off, and not an L69? They did still have carb'd F-bodies in '87. Have you found the electric harness running to the tank? If it's only a single wire back there, it was carb'd originally. The EFI cars have a 3-wire connector at the tank (gauge sender, power for f/p, and ground).

Originally Posted by //<86TA>\\

if the car is to stay carbed, the tank needs to be removed, whatever pump setup is in there needs to be removed and bypassed. After that, a mechanical pump will be fine, so long as the fuel lines are well insulated, especially if the mechanical pump has no return line. Or keep the ghetto electric pump and ditch the mechanical pump, but you still should have a return line.

You should also look into what happened to the fuel hardlines. They should be on the driverside, they are not visible in the pics, so where are they? Hopefully there is not 15' of rubber hose running under the car.

Just to continue this thought, the easiest way to bypass an OEM in-tank pump would be to get a new tank sending unit for an '84 F-body with L69 (carb motor). It'll just have a pickup tube with a screen and a new float for the gauge.

[88WS-6]

I have the build sheet and SPID and both confirm its a factory LB9 TPI car. I called the original owner today and he said that he already removed the in-tank pump. The wires may still be there. He put in an electric pump in front of the rear axle but it burnt out. So he finally installed the mechanical fuel pump which is on the block and currently feeding the carb. I took pics and got a replacement phone today so ill post them tomorrow from work

[88WS-6]

Ok here we go:

Mechanical fuel pump:


Throttle linkage:


Passenger-side of the carb:


Fuel lines:


Holley electric fuel pump:


From the back:


Back of the fuel pump again:


And a little higher up this time:


One more:



This was also a major pain because the car is very low. Stock IROC springs with 3/4 coil out of the front and 1/2 coil out of the back. Maybe an inch of ground clearance at the nose.



The previous owner also said last night that there is access to the electric Holley pump from the driver-side back seat. I didn't look, but I'm assuming he cut a hole in the floor... He mentioned that it's all wired up but he removed the fuse from that area after it burnt out. I'll pull up the carpet later today and get some more pics. He also said that the mechanical pump is not wired exactly the way he would have wanted, because he was running out of the 6AN line so he did what he could


Let me know if you'd like to see any other areas better. I wanted to take some more pics of the fuel lines in the engine bay but its just way too low to get under there without a jack.

~Matt

[sweetbmxrider]

Is the braided line really worm clamped?

Son, you have work.

I wouldn't be surprised if the fuse blew because he sucked at wiring and/or it rubbed through on the body somewhere.

[LTb1ow]

Sheet metal screws holding up the fuel lines? Legit! But hell, at least they aren't copper!

[88WS-6]

Well at least I keep it real

[LTb1ow]

That you do, driving that thing is prob very close to life threatening

If you have the time, I would start pulling it all and then reinstall what you need. And with any hope you install it bettter that guy did.

[BonzoHansen]

these sure look like low pressure power steering lines unless the photo angle is deceiving

[88WS-6]

Originally Posted by BonzoHansen

these sure look like low pressure power steering lines unless the photo angle is deceiving

Listen, I'm a driver not a thinker. They very well could be steering lines, although they run in front of the rad over to the mech fuel pump.

[sweetbmxrider]

They clearly attach to the power steering box and pump.

I'm betting the fuel lines go under the oil pan towards the driver floor.

[WildBillyT]

In the last pic those are power steering lines.


That is without question the worst Holley Blue installation I've ever seen. Starting from the tank and working forward:

1.) That's the wrong kind of fuel filter between the sending unit and the pump. A coarser filter goes back there (like a Fram HPG1) and fine filter goes up by the carb.

2.) I have never seen somebody mount a Holley pump like this in any way but straight up and down. Horizontal is just asking for trouble and it may have air issues. I'd bet that the motor itself is full of fuel.

3.) Can't tell from the pics, but it's probably not on a relay and the wiring is probably too small.