5.0 HO EFI on a 289 problems

[broncobran68]

I am putting a 5.0 HO mustang efi system from either an 87 or 89 on my '68 289. My problem is the differing firing orders. Do I just match the injectors to the spark plug that is firing. Does this create a batch firing setup? What exactly is batch firing? Will a cam swap correct my problem. Good idle quality is a must.

 

[Hydrocarbon]

I'm not sure about this, but I think you can get a engine harness for a non-HO 5.0. since they use the non 351/HO firing order.

Batch firing is when all the injectors on one side of the engine fire at once, then the other side fires all at once.

 

[Fostang]

get a 351w cam. it'll work no problem.

 

[broncobran68]

Is there a way to rewire the existing harness and avoid a cam swap and have it still run decent?

 

[mustangracer]

Mustangs Plus did a writeup on this swap. http://www.mustangsplus.com/tech/efi/

They installed a custom harness from Ron Morris, but I believe you can just unwrap the injector harness and change the position of the injector plugs to match the 289 firing order, and then put the corresponding spark plug wires in the proper order. The computer will still fire them in the HO sequence, but they'll be in position to fire on the appropriate cylinder.

 

[Fostang]

Sure it's possible but what I like to do is buy the tweecer and use it to tune to my specific set up.

www.tweecer.com good stuff to eliminate many things without tripping the computer to go into limp home mode.

Many home installed efi set ups are in limp home mode and the people don't even know just the car doesn't perform how it should and they think nothing is wrong.