Fred Allen Burge

Hello,
Theoretically speaking, if you were to install a 3.5L VQ into a different chassis and wanted to use a 3.5L ECU which one would you choose? My concern is ease of wiring and lack of extra crap to worry about so I'm thinking the earliest one I can find (from a late 01 Maxima would be the earliest I believe) and from a MT car would be nice I suppose. I'm not sure if it would need to be an early model but it seems they'd be more simple of all (maybe they are all the same). Also, I know some had trac control so I'd like to stay away from those models just to be safe.

I figure if Travis can install 3.5L's into the Sentra's and use the 3.5L ECU why can't anyone else into a different chassis instead of converting them to 3.0L timing equipment/ECU.

Any thoughts?

Thanks
Fred

nismology

iTrader: (8)

2002-2003 6-speed ECU is your best bet.

Fred Allen Burge

Do any of them not have the NATS security system?

Thanks,
Fred

nismology

iTrader: (8)

Every maxima ECU since the 1999 model year has NATS/NVIS.

Fred Allen Burge

Gotcha, so key, ignition switch, NATS module and ECU from same car. What a pain, but doable.

Fred

nismology

iTrader: (8)

They don't necessarily have to be from the same car. You can program them via the Consult so they can all work together. BTW, the ignition switch is not a part of the immobilizer system so you can use the one you currently have.



This thread should be a good primer even though it's about swapping it into an A32- http://forums.maxima.org/showthread.php?t=487345

Hoooper

if you have a 350z engine you should get a 350z ECU so you can take advantage of the exhaust VTC's

eng92

iTrader: (3)

Only the 05 300hp 350Z and newer models came with exhaust VTCs.

Also, all Z33 ecus implement a much more involved CAN system than the A33B.

Fred Allen Burge

Gotcha, so key, NATS module (immobilizer) and ECU from same car (to avoid a tow bill to the dealership), right? Sounds easier, why's nobody doing this in 4th gens?

Thanks for the link.

Fred

nismology

iTrader: (8)

Exactly.
I wouldn't say it's easier, but to me it's going to be worth it in the end. If no one else beats me to it, i'll have the next full 3.5 swap. I already have the motor, ECU, and full engine control harness. Next comes the dash harness, NATS IMMU, e-gas pedal, etc. and head gaskets since i'm going to do a partial teardown.
NP. Hope it helps.

Fred Allen Burge

How do you plan to integrate the pedal? Also, I have dash harnesses available, I work at a salvage yard, they aren't cheap but we do sell them uncut, carefully removed. They ususally run about 325$ shipped due to the huge amount of time it takes to pull them correctly.

Fred

nismology

iTrader: (8)

The A33B e-gas pedal bolts right into the where the A32 cable pedal goes. The trimmed dash harness that i'm going to use is what is going to connect the pedal to the EC harness.

Do you work at Forty Three Auto by any chance? I just looked on car-part.com and there's a dash harness for sale @ $300 and it's in Joplin, MO. There's also one in Oklahoma for $250. Decisions, decisions.

Fred Allen Burge

Why yes I do . We don't really do any price matching with the other yards on wiring harnesses though, it's just not worth the work for less than what we ask.

Fred

nismology

iTrader: (8)

Awww, that's too bad.


Do you perchance have any 2002-2003 6-speed shifter and cable assemblies??

scrhale

Using an 02 Maxima with its parts as states is definitely the easiest way to go about a full 3.5 swap. Trying to use Altima parts (or who knows which other 3.5 Nissans) causes the havoc that JClaw went through. If you use the A33B ECU then you will not have any BCM hell.

vsamoylov

02-03 would be your best bet.
harness has to be from a mt maxima (auto different)
gas pedal direct bolt it
theres nothing that has to be done correctly to pull an engine harness.

nismology

iTrader: (8)

Post #2.
It's not absolutely necessary to have a manual harness.
Post #12.
We're talking about the main (dash) harness, not the engine control harness.

vsamoylov

the same thing goes for the dash harness as for the engine harness.
mt and at engine harness are different and so are the dash harness.

eng92

iTrader: (3)

They are different of course, but the point is that the parts that are different do not matter when it comes to doing a swap this way.

Both my engine control and main harnesses came from autos.

scrhale

I can't wait to see Nismo's finished product ... that car is going to be sick

Broaner

iTrader: (10)

What happened to the Megasquirt Fred?

I've been wondering for a while now what exactly is involved with this NATS stuff. How does it work exactly? Does it just act as a relay supplying power to the ECU? Could it not be possible to bypass those systems by giving the correct voltages directly to the appropriate ECU pins?

Fred Allen Burge

Nothing, just looking into this as an option for future projects.

I'd think so but I'm not sure if anyone's tried it yet. It seems like a very simple system.

Fred

JClaw

iTrader: (17)

Yeah for the love of god please do yourself a favor and do the complete Maxima 3.5/VTC/6-speed/ECU/Cluster/E-Gas/Dash deal all from the SAME car.

And for the record, I have no idea what a 2002 Maxima e-gas pedal looks like but the Altima 5-speed E-gas pedal I had came NOWHERE near to fitting bolt on in a 4th gen. Not even close.

Fred Allen Burge

As I read the diagrams it looks like there's only one wire between the ECU and the NATS module.

Does anyone understand what is happening electrically on that line?

As I read it it seems like the NATS module is looking for a radio signal of some sort from the key, when it sees it it sends a signal to the ECU that says "ok, the original key is present, now allow power to the coil packs and injectors".

Seems like the ECU just needs to see some sort of voltage on that line before it will power up the injectors and coil pack, right?

thanks
Fred

eng92

iTrader: (3)

Here are a couple of scope screenshots that I took monitoring the voltage on the NATS module output to the ecu relative to ground. It is the BLUE waveforms that are of interest (ignore the RED)





As you can see, it is a PWM signal that increases in frequency when the key is turned to the ON position. The higher frequency is maintained until the ECCS relay drops out several seconds after you turn the key off.

The thing I found interesting was that if you look closely at the waveform after the key was turned, there is a distortion in the 5th, 7th, 8th and 9th pulses. At first I thought it was just some voltage transients but I repeated the test 14 times and it was the same every time.

Try duplicating that.

nismology

iTrader: (8)

I'm willing to bet every single NATS output waveform is unique. Impossible to duplicate IMO. You wouldn't even know which particular signal the ECU is looking for in the first place.

Excellent info as always...

Fred Allen Burge

Nice work, thanks, I'm suprised that little box does that much.

It would be much easier to just buy the ECU and steering column w/ key from a salvage yard from the same car, not too hard to do really. Just look up an ECU on car-part.com, when you find the one you want call the yard and ask them if they still have the steering column with key from the same car. And ask for the plugs for the NATS, and ECU to be cut off (actually the NATS harness may be a seperate sub-harnessfrom the dash harness so it may come with the column anyway, not sure).

Then I'd wire the NATS module up close to the ECU and fasten the new key to it permanently. Once that little chore is done it should be like any other motor swap (except for the accelerator pedal which would take some fabrication on a non-maxima). Which brings me to my next point/question:

I don't think the e-gas pedal setup is necessary, it simply tells the TB to open and close, I don't think the pedal mounted TP sensor talks to the ECU, only the TB mounted one does. So, if you modify your electronic 3.5L TB like I have on my project I think you could just use your old throttle cable setup.

http://www.engineswaptech.com/photos...8/500x374.aspx

Fred

eng92

iTrader: (3)

2 different harnesses. The NATS connector is part of the main harness and the ecu connector is part of the engine control harness. I had to make my own NATS module connector because the original one was cut off the dash harness at the salvage yard.

Not true. The pedal mounted sensor is wired to the ecu and the ecu controls all throttle motor movement including cruise control.

It should not be too hard to mount the maxima pedal in another car. It bolts to a vertical surface (cabin side of firewall) with 2 bolts. You just have to move it up or down before you drill the mounting holes to get it the right height from the floor mounted pedal stop.

vsamoylov

Let me say this again the 2k2-2k3 e-gas pedal is a direct bolt in into a 4th gen maxima.

dont foget about the chip in the key as well.

Fred Allen Burge

Gotcha, now that's crazy.

So, which TP sensor is the ECU using for accel. enrichment and such, the one on the pedal or the one on the TB?

I guess the pedal mounted TP sensor tells the ECU how quickly you WANT the throttle to open and how much. Then, the ECU tells the TB how quickly it's actually GOING to open and how much. And then perhaps the TB mounted TP sensor then tells the ECU if it actually DID happen.

That's taking it a little too far in my opinion.

Fred

nismology

iTrader: (8)

That whole process takes less time than you think. It's an imperceptible delay IMO. And i think the fact that the 2k2 ECU processes signal inputs much faster than the A32 ECU would negate any perceived advantage of a cable-actuated throttle.

Fred Allen Burge

I don't doubt it's very very fast, that's not what I don't like about it. I just think it's a little overcomplicated, what's the main benefit of this system, easier traction control?

It's not like it really matters, I have no say in what Nissan does, I just have the interesting task of reverse engineering it for fun projects!

Fred

eng92

iTrader: (3)

It simplifies things mechanically as there are no longer any separate idle air and cruise control systems to deal with.

eng92

iTrader: (3)

Read a little more closely and you will see that we are talking about a VQ35 swap into any chassis, not just the A32.

Broaner

iTrader: (10)

This is what I'm talking about. Everything getting overcomplicated because the consumer is the typcial spoiled *****. An IACV is not required on any motor. I feel that all such technological advancements are not actually advancements but just another method to garner the consumer dollar.

nismology

iTrader: (8)

Neither is direct ignition, EFI, or OBD. Let's dump all this modern tech and drive 8 liter V8 boats that get 8 MPG highway on a good day.

krismax

iTrader: (15)

i disagree i see what he's saying ,i look at things that add cost to a car that def arent needed for power or gas milage or emissions . I see things that hurt all three on my car. the AC and PS soleniods def not needed .take them off you will prob have better MPG and they are parts that cost something and add weight and wires to the car. the IACV isnt needed the screw on a TB would adjust it fine but NOOO they need to do it the hard way.

If you want to look at a example of them making someing more complex compare 95 and 96 evap setups on maximas.

I love the new car Techs but the way i see it cable TB's werent a problem DONT try to fix them then.

Fred Allen Burge

I think the real issue is that cars have become so refined and comfortable in the last couple decades that they are searching for ways (however small and expensive) to improve on them. They can justify spending a few hundred thousand dollars developing an IACV system that allows you to idle a couple hundred RPM lower if it makes the car more comfortable for the soccer moms and possibly reduces idle emmisions. I guess.

Fred

nismology

iTrader: (8)

Bottom line is this...if i have to use e-gas (which isn't all that bad BTW) to keep VTC's on my 3.5 swap that's what im gonna do.

Broaner

iTrader: (10)

I'm not argueing with your bottom line. I'm just posing the viewpoint. To counteract your statement. I'm sure VTC's could be designed by the manufacturer to work with a typical TB setup.

To get off topic a bit, I think all performance oriented models should be offered in bare bones trim. I'm not expecting them to sell cars with sheet metal interiors. As an example of the modern performance car I think a special model 350z should be offered with a manual steering rack, no AC, manual windows and seats, no sound deadening, etc... Full interior would probably be required to make it seem not cheap. It makes since to me. The car would be cheaper for the manufacturer as well as the consumer.