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Old 04-06-2018, 08:16 PM   #1
chevy only please.
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Question L05 with 480LE swap to l31 with 480lE

Hey everybody! I have an Isuzu npr commercial truck that runs a l05 engine with an 480le(w/o mlps) transmission perfectly. However I would like to add more power and torque to the truck by adding an l31 motor. Im not sure how the current l05 works with the 480le because arnt the 480le trans electronically controlled?and i dont see a exterior tcm. and theres not one on the trans.

Anyways...

Can i just swap in a l31? Will it work with the older 480le without the mlps?. or do i need the newer 48ole with the attached mlps? and if i need the newer trans then im assuming i would need the wire harness, ecm and new lines to the transmission cooler. to go with it?

also there are 96 and up isuzu npr truck that run with an l31 stock. im just not sure what transmission they come with.

also would a lo5 wire harness work with an l31 motor?

thanks for any input at all!

Last edited by chevy only please.; 04-06-2018 at 11:26 PM.
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Old 04-06-2018, 09:55 PM   #2
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Re: L05 with 480LE swap to l31 with 480lE

I'm GMC, so am not allowed to play here Hey wait Mr. Chevy Only Please, did you say you have an Izusaroo... I mean Isuzooka... er is it Isuzu? That's it, Isuzu! I guess maybe i can play after all. I am sure your truck has an ECM for that trans somewhere. In the earliest trucks, such as a '91 Suburban, it is under the dash behind the glovebox. I had a '91 with 6.2 diesel that was not computer controlled at all, but it had an ECM for the 4L80E because those are electronic transmissions. If you go with another engine that was available with 4L80E then you will need that ECM I would think. There are two VSSs on this transmission. It all matters since the trans reies on signals to work.
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Old 04-06-2018, 10:16 PM   #3
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Re: L05 with 480LE swap to l31 with 480lE

Thanks for the input. i will be looking for this tcm again because i am pretty sure as well it has one. maybe it is programmed internally to the ecm who knows.

also need to know if the l05 harness will work on the l31. and if somone can elaborate on that.

i will add pics of what i have soon when it stops raining.

Last edited by chevy only please.; 04-06-2018 at 11:27 PM.
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Old 04-09-2018, 05:29 PM   #4
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Re: L05 with 480LE swap to l31 with 480lE

Is an LO5 a 305? If so, its a direct swap.
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Old 04-09-2018, 08:48 PM   #5
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Re: L05 with 480LE swap to l31 with 480lE

LO5 is a TBI 350(87-95)

What fuel system are you going to use? If you use the TBI system(with a new intake manifold) you will be able to use your factory wiring harness.

Everything will physically bolt right in. All your front accessories and your exhaust manifolds will bolt on.
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Old 04-09-2018, 11:57 PM   #6
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Re: L05 with 480LE swap to l31 with 480lE

95 s tucker thanks you so much. I will want to keep the tbi. And get the new intake. Now awhen I do get the new intake and put it on that l31will I need any kind of tuning? Or timing advance or anything? Or is it just plug and play?

Also if you have the time to throw some links of what I would need that would be great.

Last edited by chevy only please.; 04-10-2018 at 12:02 AM.
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Old 04-10-2018, 08:14 AM   #7
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Re: L05 with 480LE swap to l31 with 480lE

You may need tuning. You may not.

The intake manifold:

https://www.summitracing.com/parts/nal-12496821

If you plan on using EGR(if your current engine has it) you will need to use a vortec left exhaust manifold with an EGR tube. I don't know if your NPR has EGR or not. If you don't need EGR, you can use your factory exhaust manifold, and install an EGR block off plate on the intake manifold.
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Old 04-10-2018, 04:51 PM   #8
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Re: L05 with 480LE swap to l31 with 480lE

Get a TBI chip burned with programming for a mexican 400SS. From the factory its a vortec with TBI.
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