3.4 swap help

[JamesDean91]

Okay so I am swapping out my 98 3.4 for a 97 3.4 with a lot less miles. I have run into one hurdle I hope won't affect much. First off I really don't want to swap my 98 engine harness onto the 97 block.
My issue is the new engine has the vacuum idle on the power steering. My 98 had the electric plug. The 98 also had a supercharger that will be going onto the 97 engine. Does anyone know where I need to T in the vacuum line?
Also my intake tube has no spot for the return line that fed into the intake past the maf sensor so can I just vent it out in the engine compartment somewhere?
Does anyone know if running the 97 engine with the 97 engine harness will affect the 98 ecu? The plugs look identical and I don't see why it would affect anything.
Any help is appreciated thanks.

 

[kolelt]

How hard could it be to swap a harness when your swapping the ENGINE ?

 

[4Runnermex]

Okay so I am swapping out my 98 3.4 for a 97 3.4 with a lot less miles. I have run into one hurdle I hope won't affect much. First off I really don't want to swap my 98 engine harness onto the 97 block.

My issue is the new engine has the vacuum idle on the power steering. My 98 had the electric plug. The 98 also had a supercharger that will be going onto the 97 engine. Does anyone know where I need to T in the vacuum line?

Also my intake tube has no spot for the return line that fed into the intake past the maf sensor so can I just vent it out in the engine compartment somewhere?

Does anyone know if running the 97 engine with the 97 engine harness will affect the 98 ecu? The plugs look identical and I don't see why it would affect anything.

Any help is appreciated thanks.

Look at the harness end where it all plugs to ecm.

They have model numbers, it they match your fine if they don't your truck will turn but won't start. Had this happen to me once. Ever since I keep the truck harness with new engine. It has to be done no other choice. I can tell it's probably different since you have a plug for the PS pump sensor.

Engines are identical 96/00 vacuum lines and all. Except harness

Changes at 01/02 with the electronic throttle body . Single cable

 

[4Runnermex]

How hard could it be to swap a harness when your swapping the ENGINE ?

Piece of cake. While you have everything off take advantage and drop some valve cover gaskets if needed. You'll be taking the whole top off the engine to swap the harness

 

[St Runner]

I would do some research before swapping out the engine harness. The early year ecu was different for every year so you would have to change out the ecu as well as the harness. This might lead you to more problems than just a vacuum line. You need to match the wiring side by side with the fsm (97 to 98) to make sure the wiring is compatible. When I did my 5 speed swap on my 97 the ecu and wiring harness were different for the same year auto to manual. Since the engine blocks are all the same no matter the year would it not be easier to replace all the power steering to the 98 model?

 

[Doc2012]

Wow.

You guys are all about swappping the harness.

How about just swapping the PS Pump, and plugging the vaccum line where ever it goes?

 

[4Runnermex]

Okay so I am swapping out my 98 3.4 for a 97 3.4 with a lot less miles. I have run into one hurdle I hope won't affect much. First off I really don't want to swap my 98 engine harness onto the 97 block.

My issue is the new engine has the vacuum idle on the power steering. My 98 had the electric plug. The 98 also had a supercharger that will be going onto the 97 engine. Does anyone know where I need to T in the vacuum line?

Also my intake tube has no spot for the return line that fed into the intake past the maf sensor so can I just vent it out in the engine compartment somewhere?

Does anyone know if running the 97 engine with the 97 engine harness will affect the 98 ecu? The plugs look identical and I don't see why it would affect anything.

Any help is appreciated thanks.

Ok here are two pics of two different harnesses. They have model numbers if they don't match they will not work. Keep your harness that's in your truck and swap out whatever you need from old engine to new engine. Not really much choice.. Take pics of your engine prior to removal front, sides vac lines and Tranfer whatever you need to the new engine.

Trust me on this one I've done over 50 3rd gen swaps. Yes over 50, and I always keep the harness with the truck unless there are identical model numbers.

 

[4Runnermex]

Wow.



You guys are all about swappping the harness.



How about just swapping the PS Pump, and plugging the vaccum line where ever it goes?

I willing to put money that I'm right... It seems simple to swap the PS pump that's a duh!! Move.

Count the pins on the 98 where it plugs into neutral safety switch. 98 has a few more than the 97. They look so similar but slightly different.

Match the model numbers on the harnesses and you won't have to swap nothing. They don't match then swap!!

So easy yet some get technical.. I'm sure there will be others that have done as many swaps as I have done that would agree. Thedurk is probably one.

 

[JamesDean91]

Thanks for the help. Looks like i am swapping harnesses