I bought an 03 5.4 for my 97 a few days ago.
i was wondering if i should use the harness off the new one or my old motor.
I would like to use my old one becuase the O2 sensor plugs on the 03 are different and a few other things like the nock sensor etc.

But my old intake manifold had the divided lower intake plenum (not sure what the name of it is) and the new one doesnt.

so if i used my 97 harness and just left that thing in the front of the old intake manifold unplugged would it still run right.

Also i am doing long tubes and a full exhaust at the same time.
would it be safe to drive it without a tune for a week or so with PI heads and longtubes on a tune for a 97 5.4

 

Sorry but I'm not totally understanding the question.
Are you talking about just the wire harness?
97 and 03 have to different setups.
97 runs on 2 coil-packs with plug wires.
03 runs on 8 COPs (coil on plug).
You can run the 03 on ether one .
But you cant swap intake manifolds between the two!

Phil

 

Yes, if it's a 4.6. The 5.4 always had COP.

 

no both motors have the COP's

i know i cant run the 97 intake manifold on the 03

What i am asking though is on the front of the 97 lower intake plenum there is a sensor/motor thing that opens and closes inside the intake manifold. i can take a picture if needed it's hard to explain.

the 2003 intake manifold does not have this.

so if i use the 97 harness and the 2003 motor and left this unplugged since the 2003 motor doesnt have it is it still going to run right.

 

Everything I have researched says use the new engine with new harness. I am putting a '02 in my '97 and don't see any major problems. Biggest so far will be the heater hose relocation and that is not a big deal. I am also running LT's and all new exhaust, I plan on using the 2 upstream O2's with a longer pig tail and just programming out the rear 2. I've got both engines out and didn't notice an O2 problem, I'll look at them again tonite.

 

Always use your old harness, - IF you can. There's more things that are different than you realize at this time. To use the new harness, you should have the doner PCM, which is better unless the instrument panel is different.

You also have PATS integrated into the newer harness. You need to deal with all this before and after installing the new harness vrs eliminating the tuning valve operation. Either way, a tuner may be needed.

Look to JMC's notes in the "How to" section on this site.

 

BTW- That is your IMTV. = IntakeManifoldTuningValve.

 

Think that's what I refer to as the ICRV Intake Control Runner Valve.

What you need to do and maybe someone can chime in and correct me if I'm wrong, But take the ICRV off the lower plenum from your intake and plug it into the harness. and attach it somewhere out of the way. If you dont you will most likely get a cel from this, however if the pcm senses that its doing something than you can just remove its function from the pcm via a custom tune later.
And you should be able to run that motor without a custom tune. However it would probably run better with a custom tune

However I would trust JMC and Jbrew's information These guys are spot on. (most of the time)

 

I believe your referring to the IMRC (IntakeManifoldRunnerControl) Regardless, that's a 3.8 and 4.6 deal. 5fours don't use runners. Now you know

 

Now I'm maybe slightly confused as you say 5.4 doesn't use runners. but the 4.6 and 3.8 does? But the 5.4 uses a intake manifold tuning valve?

So the 4.6 doesn't use a Intake manifold tuning valve? If that's the case I'm going to have get busy with my camera taking some pictures.

cause when I did my 5.4 swap I didn't end up with any empty plugs
or forlorn devices without a home.
In other words the 4.6 and 5.4 intakes both had the intake manifold tuning valve?

Unless they perform the same function and have the same plug.? I'll get some pictures so I can sort this out.

Anyway thanks for clearing that up


Got this sorted out The 4.6 and 5.4 both have the IMTV, However the IMRC is only on V6 models. I was starting to get all confused as to what went where? However I verified this my chiltons manual. So its possible the chilton is wrong, However when I swapped My 4.6 to 5.4 I didn't have to worry about the IMRC .

So to the OP follow the above directions however the thing your referring and I was referring to is called the IMTV (thanks Jbrew)

 

I left the imrc unplugged, and zip tied the harness out of the way. No cel from it not behing there. Its spring loaded so voltage is applied when needed. 2 wire setup. Don't think the truck even knows, and if it doesn't it don't care its missing.

 

whats' wrong with the NPI to PI adapters???

 

Damn man - No I was wrong about the 4six , on purpose. Was trying to make you right at something. You caught me. Mannn...

 

thanks for all the info.

i used the old wiring harness out of the truck. but i had to use the vaccuum harness off the new motor.

I got the motor in and started tonight.

I was amazed at how good it ran and idled because i still have some vaccum stuff to sort out, the IMTV isnt there any more, i havent plugged in the rear O2 sensors, and i havent tapped the intake manifold for the other sensor

I have some more questions though.
there is a plug on the harness down by the power steering pump that goes into the lower water neck.

then there is another plug on the harness that can only go about eight inches from there. where the hell does this go?

i looked for ever and couldnt find anything for it to plug into.
I can take a picture of it if needed.

and once i get all the little stuff finished up it will be okay to drive for a while without a custom tune?

im just worried about it running lean i could care less if a check engine light comes on.

it sounds amazing with just long tube headers and cats haha

 

im not really sure what you mean.

I swapped in a junkyard motor out of an 03 into my 97 not just the intake manifold.