Wiring help in swap(2.5 to 350)

I swapped a carbed 350 in place of a FI 2.5, Im having trouble wiring 350, I got the starter to make noise but it wont turn over, and I need to know what fuel pump to use with this motor. thanks

It makes noise but won't turn over huh? What kind of noise? The starter is simple. 12 volts constant to the large connection, 12 volts (when cranking) to the small connection. Your battery might not have enough juice to turn the larger motor or your starter might not be good. You can use any low pressure in-line pump with that motor. You can find those at Autozone or other auto parts stores. Wire it in with a relay to the ignition switch.

It sounds like its engaging but wont turn, and what do I do with the stock fuel pump in the tank? and will that be enough pressure or do I run that to the mechanical pump thanks.

That would be without a mechanical pump. If it has a mech. pump on it, try it with that and see how it works. Pull the sending unit and remove the in-tank pump. You might have to attatch a piece of hose somehow to keep the sump on the bottom of the tank, you don't want to use that pump though, it'll provide too much pressure.

Check your battery connections and the pos cable connection on the starter, it sounds like it's not getting enough amperage to turn the motor. Also check to make sure you're getting enough voltage, maybe try hooking a auxilary starting box up to it if you have one.

Alright I will give that a try, thanks for the help.

I would suspect a bad ground to the engine block first, since this in not the most obvious connection in an engine swap.

As far as the fuel pump, you definatly need less pressure than the stock electric pump. I am not sure how the stock pump would respond to adding a low pressure restricting pump, since the stock 4.0 pump returns excess pressure as fuel to the tank. A standard inline regulator will just stop the fuel flow. The mechanical pump may work, but I would think the stock pump would be better if you can get the pressure down.

I have never seen a SBC in a Cherokee (would love to), but I am guessing the stock fuel pump would be real close to the right motor mount and you would like to see a blocking plate there instead.
MoFo

Its not as tight as you would think, When I get back from school today I will post some pics of the engine in the XJ.

For the fuel pump use the stock pump and get a good fuel pressure regulator with a return line to send excess fuel to the tank. I believe it should be set at 7-10 lbs for a carb if my memory isn't shot. As for the starter I'd have to agree with checking the ground to the motor, if that aint it we'd really need to know what kinda noise it is. It is the starter for the chevy right? Not the one for the 2.5?

Yes its the starter that came off the 350, and the noise it makes sounds like its tryin to engage but wont turn??? if the that makes sense?

JT86XJ said:

I swapped a carbed 350 in place of a FI 2.5, Im having trouble wiring 350, I got the starter to make noise but it wont turn over, and I need to know what fuel pump to use with this motor. thanks

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you will need to get a pressure regulator to lower the fuel pressure from the in tank fuel pump. crazy is right set it to around 7-8 psi. either that or get a tank from an xj with a 2.8 in it.

cherokeepimpin said:

you will need to get a pressure regulator to lower the fuel pressure from the in tank fuel pump. crazy is right set it to around 7-8 psi. either that or get a tank from an xj with a 2.8 in it.

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The XJ with the 2.8L used a carburetor and a mechanical fuel pump, so this would indeed be the best long-term solution. Although even with the 2.8L tank I would run an electric fuel pump designed for carburetor applications rather than the mechanical pump. I lost an irreplaceable engine in a 1939 Hudson coupe I was restoring when the diaphragm in the mechanical fuel pump burst and filled the crankcase with gasoline. It wasn't pretty.

You won't be able to just swap the tanks or even the sending units from a 2.8L jeep. The tank is the same and the sending unit would fit but it's not compatible with your guage. The ohms rating isn't the same. Also, the sending unit is welded onto the draw line that goes to the bottom of the tank so you can't just switch the sending unit from the 2.8 to the 4.0.
The 2.8 had a mechanical pump so there won't be a in-tank pump either. Low pressure pumps are cheap, less than $40. Save yourself the time and effort and just put a inline pump on. Also, you'll have to disconnect the current in-tank pump, that wouldn't be hard though.
Or see if you can find a pressure regulator with a return in it like was mentioned before.