Computer

[89pathfinder]

What exactly does a computer on an older vehicle do? A computer in something like my 89 Pathy. What does it control and is it needed. The reason i ask is because over the summer I plan to save up for a new motor and transmission. The motor is well, its old 230k miles. Its had a good life, and so has the transmission. But I'm looking for something with a little more nut. Ive narrowed my choices to an older Buick 3.8L v-6, or a newer GM 4.3L Vortec v-6.

 

To my knowledge a computer was specific to a type of engine, that controls functions on the engine like warning sensors and things like this. So what I am asking is there a need for the the computer? Or is it possible to use my existing computer on a different engine, something with fuel injection?

[GhostPath]

What exactly does a computer on an older vehicle do? A computer in something like my 89 Pathy. What does it control and is it needed. The reason i ask is because over the summer I plan to save up for a new motor and transmission. The motor is well, its old 230k miles. Its had a good life, and so has the transmission. But I'm looking for something with a little more nut. Ive narrowed my choices to an older Buick 3.8L v-6, or a newer GM 4.3L Vortec v-6.

 

To my knowledge a computer was specific to a type of engine, that controls functions on the engine like warning sensors and things like this. So what I am asking is there a need for the the computer? Or is it possible to use my existing computer on a different engine, something with fuel injection?

 

Your existing engine is computer controlled fuel injection, just a primitive version of it. Whereas later Pathfinders have multiport fuel injection (one injector per cylinder installed in the intake manifold runners pointing at the intake valves), you have two (I think) fuel injectors in a throttle body (looks like a carb, but it's not) that provide fuel to the entire engine.

 

On your truck, the computer controls (at least):

Ignition timing (advance/retard)

Ignition firing (whether to fire at all)

Fuel injection (how much fuel to input, when to input it, etc.)

 

If you have an automatic transmission, the engine computer talks to the transmission computer to determine optimal shift points and how/when to shift depending on what you're telling the truck to do. Unfortunately, as nobody has yet deciphered the communication protocol for the transmission computer and there is no such thing as a *non* computer controlled 4-speed auto from Nissan, the automatic cannot be used in conjunction with a non-Nissan engine - whether carbed or fuel injected.

 

Also, be advised that many localities have passed laws making the installation of an older engine in a newer car illegal. If this is the case for your area, it means that you can only put an 89-or-newer engine in your Pathfinder.

 

Despite what certain critters from the Southern Hemisphere have said, I do not think that a GM motor is a very good swap for the Pathfinder. In the case of the 4.3, the engine is heavier and less fuel efficient, and in either the 231 or the 4.3's case, you're going to have to do a LOT of fabrication just to make it work. There are no US market kits that I am aware of to do such a swap.

 

Personally, if I was looking to do a swap, I would find a wrecked Frontier with the supercharged VG33 and take its driveline and computers. Or just a regular Frontier with a VG33 and put a Stillen blower on it. It is very nearly a direct drop in and requires minimal modification to the truck. And you're looking at up to 300-350hp with modifications, if you so desire.

 

While it is possible to tweak or reprogram a Nissan engine computer to run another engine, it's generally considered a bad idea and doesn't work well. Generally speaking, it's preferred to take the donor vehicle's computer and use it instead.

Edited January 16, 2008 by GhostPath

[unccpathfinder]

well if you have an auto trans your going to want to make that an MT since it pulls data from the ECU...im not sure on the other wiring...I guess you could disconnect the ECU and turn the ignition key to on and see if all the other functions still work...but I have a feeling your going to have problems...

 

4x4parts may be a better source for swap information...

[89pathfinder]

It is a manual transmission. Im pretty sure i wouldn't have a problem putting an older engine in, law wise. The 231 was the one i had in mind. So if i had a engine with a carb, would i run into any problems?

[GhostPath]

I'm assuming that since the 231 is carbureted rather than injected that it's not the turbo 231.

 

Why are you replacing a 145 horsepower engine (the VG) with a 125 horsepower engine (the carb'd 231)?

 

You would also have to install a GM transmission and transfer case as you cannot bolt the Nissan trans to that engine.

Edited January 16, 2008 by GhostPath

[eglaisi_91pathy]

Ok, don't take this the wrong way. If your not sure what a computer does, than maybe you shouldn't be engine swapping. It may seem not too bad in theory, but as we all know, there is always hangups... some bigger than others. Plus, theres always something you didn't think of. If your dead set on swapping, I personally would keep it in the family (nissan). Above mentioned Supercharged VG33 from an 01-04 fronty would be my pick if I wanted to swap.

 

Again, I didn't mean to be a dick about it and didn't intend to hurt anyones feelings in what I said.

[zonianbrat]

I say drop a crate 350 witha trubo 400 tranny with a shift kit .in her and be done with it. Or do what people have said above and go with a fronty motor. Either way you will run into some headaches. It is simply the nature of tinkering. I am sure a 350 would involve more fabbing and possibly some suspension modification to compensate for the extra weight. So it is really up to you. I say go balls out or get the f$%k out!! Just my .02. And not do be an ass eglaisi 91. But I doubt 1/2 of the people that do engine swaps involving ECU's actually know off the bat what all it controls. Most of them just know to wire it back up the way it was in the previous vehicle or how to follow a schematic in order to do so.

[94extreme]

may want to PM or email mr Vsicks Pathy as he's got a holden and an mt in his truck

[GrimGreg]

IIRC AC sells motor mounts for 4.3L GMs to be used on our trucks. You can buy aftermarket fuel injection computers that will work with most motors, the hard part is getting your stock guages to work, temp and tach specifically.

 

I would agree on trying to find a 3.3L Nissan and just swaping the engine and computer, they will bolt up to your tranny and or t-case and stock motor mounts without modifications or adaptors. I wouldn't go with a super charged version though unless you want to buy only Premium gas.

[89pathfinder]

I realize i cannot use the tranny i have, and probably not the transfer case. I also realize that i will probably run into a ton of problems. But the reason i chose that engine was because it would fit easily in the engine bay and it was not fuel injected, so in theory easier to install. But this has got me thinking that a 3.3 would probably be my best bet, installation wise.

 

So a 3.3 would bolt to my existing motor mounts?

[GhostPath]

IIRC if you get the 3.3L out of a Frontier, yes, it should drop right on to your existing lower motor mounts (the brackets on the frame).

[sw]

in answer to your question no you can not use your current computer to run a different motor. you will need the one the new motor comes with or an after market one - then it will need to be mapped on a dyno

 

even if by chance it had all the right sensors & configuration the fuel mapping would be up the creek

 

the previous coment concerns me. you need to realise that there really isnt much at all thats 'bolt in' when it comes to swapping in a completely different motor. even if some companies advertise fabricated mounts & such.

Edited January 18, 2008 by sw

[89pathfinder]

I realize that, all i meant by that was can i use my existing motor mounts.