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Kingman

TBI to Z31 MPFI swap

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I've read this entire thread and am in utter awe! Great job! Can't give enough Kudos for this one. This may be saved in my archives if I ever attempt to get mo' powah!

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Lol thank man. :beer:

 

One thing about the Z stuff though, they do have a little bit of an appetite for fuel injectors. I lost the number 1 cylinder injector not too long ago and in replacing it I messed something up pretty good because it sputters and kicks under load from 1/4 throttle and up. It all just seems to fall apart and it's annoying.

 

I swapped distributors before replacing the injector, I think the problem lies there. There's something about the way the Mitsubishi and Hitachi distributors are that makes setting them in a little different. I think I just got the dizzy a tooth off. :shrug:

 

I'm going to spend another day tomorrow going through everything.

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I'm looking to swap my TB for a MPI from a 96 or newer pathy so I have the OBDII system. I think you will become my best friend! Where did you get the schematics for your 88? I have a manual from auto zone but the diagrams arn't as good as the PDF FSMs.

James

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I'm tellin' ya, you're going to hate all the emissions crap on that!

 

I've got an ass load of wiring schematics that were copied from Mitchell manuals at the library. I also have the downloaded '84 300ZX FSM and used a combination of 3 sets of schematics to sort everything out. I had Mr.510 get a copy of the ECCS schematics from his brother who works at Nissan.

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ya screw the 96+ electronics. If you want more than the 90-95 ecu offers build a megasquirt.

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ya screw the 96+ electronics. If you want more than the 90-95 ecu offers build a megasquirt.

I want OBDII because it give more feedback and its what I'm used to now. I would prefer a stand alone system but what would that cost?

Forgive my questions I have been out of automotive and running milling machines since 04. Before that I was in fleet repair since 94. I've only been playing with my titan. I have the Uprev tuning software for it but haven't screwed with it much. Even when I was working in the automotive field I mostly did repair and mild upgrades, I never did any major swaps like this. Also remember I'm old! Back in my racing days (teen years) if you wanted more fuel you put a bigger carburetor on it.

James

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My1path and Kingman, I hope y'all happy! Now all I think about is building a VG! I'm getting eye strain from trying to surf VG sites on my phone at work. Now I have to build a VG33.

I've been studying as much as I can lately.

I see y'all point about the OBDI system. It looks very easy to program. My brother is a computer tech so burning eproms is no problem, they have all the equipment to do it. So I guess I will need the injection system, harness and computer from a 94 or 95 pathy, but use the intake and injectors from a 3.3.

As for the motor build Nissan Nut pretty much covered all of that so I will just follow his build but put some aftermarket cams and do some head work.

It's a pity a VQ30DE won't fit in our trucks, Jim Wolf has a schematic on how to wire one in a dune buggy or race car with a maxima harness. Looks pretty easy and there are a couple in the local pick a part. That would be pretty under the hood of a WD21!

According to this site,

http://grannys.tripod.com/2N6VG30.html

And quite a few others, all the VG blocks are the same whether they came out of a front wheel drive or rear wheel drive. So a quest or villager motor should work too. From what I'm reading all VG33 are non interference motors. Only the VG30 was interference.

So now I need to start collecting parts. My wife is going to be pissed!

James

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the nissan vehicle 3.3's are still interference but the chance to his is less likely because they run a smaller cam. BUT if you put a performance cam in there you are back to having an interference motor.

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The truck has been sitting for a few months due to a horrific misfire/ sputter that I just could not figure out. MY1PATH's '89 fried an ECU which got me thinking, so I looked inside mine and found a bbq'd resistor. Don't know what it's to. I replaced the ECU and it runs perfect again. I haven't been able to find the cause of the burned up resistor. It may have been a fluke thing or something, somewhere, is loading it down too much. It took about 2-3 months for the resistor to burn up so I might not know if it's "fine" until another 2-3 months. :lol: We'll see.

DSCN0278.jpg

DSCN0279.jpg

 

I made a video my new camera. I'm still quite fond of the intake noise. :D

http://www.youtube.com/watch?v=NhdP89wyaKs

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Just read through this whole thread. Engine sounds awesome.

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Thanks man. :beer:

 

Carrying over from the other thread, the leaking IACV that "fixes" it's self when hit with a hammer is pretty weird. I think it's either a bad diaphragm inside or the seal on the idle screw it's self. Not sure rally but I won't tear it apart until I have a new good working unit. Which is kind of being difficult to find...

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So, the z31 engine is officially a VG30E right (unless you have the turbo version)? But clearly it isn't identical to the VG30E in most pathfinders. So, how much do they change and still call it the same thing? I guess basically here it is the intake and ECU? Maybe the cams are different? What lift do the z31 cams have?

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Yes, they are VG30Es. The engine was first produced in '83 for the Z31 chassis. All Z31s use the same cams, NA or Turbo. The MPFI Pathfinder cams are the same as the Z31s but are different than the TBI Pathfinder cams.

 

The difference in the cams is due only to an update done to the engine. A/B series from '84-3/'87 and the W series from 4/'87 to present (they are still used in a truck in Saudi Arabia). The A/B series cams have the same lift but a longer duration than the W series cams. The only factory cam to show an actual HP/TQ increase are the European cams which have both a higher lift and longer duration. These are the factory cams to have.

 

VG30E means MPFI. VG30I means TBI injected. Any VG30 that is MPFI is a VG30E no matter what chassis the engine is in. VG30ET means MPFI+Turbocharged. VG30DE is DOHC MPFI, etc etc.

 

The Pathfinder intake plenum DOES NOT flow that much more than the Z31 plenum in stock form, I have seen various flow tests done that confirm this. The intake plenum design with the long runners does increase the low-end torque of the motor however the Z31 intake pwns it in equal air distribution. Gutting the plenums is an entirely different story as the numbers and flow ratings change astronomically. I will be doing a dyno test on my Z with a gutted plenum as soon as it's installed.

 

The ECUs of course have different fuel maps and what not. "Performance" sports car VS. an SUV. Another cause for the increase power in the NA Z platform is the better exhaust manifold design and larger piping, which is actually pretty damn good for stock.

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I put the cover on too. Had to cut 3/8" off the back to clear the firewall.

 

DSCN0683.jpg

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You forgot to mention that the firewall has to be cut to use the Z31 plenum opposed to the WD/D21 plenum. :tongue:

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You forgot to mention that the firewall has to be cut to use the Z31 plenum opposed to the WD/D21 plenum. :tongue:

 

Forgot to mention? You're kidding I hope. :lol:

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I'm gonna make a quick list of the things that have gone wrong with it.

 

Throttle cable frayed and jammed

Alternator went bad

IACV went bad

Cracked throttle body couplers

Blew a piston ring on No. 3

No. 1 injector went bad

ECU resistor fried

Electric fan switch went bad

RMS started leaking

Varnish on one of the lifters making it tick randomly

MAF went bad

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Yeah but the engine was free so I'm not complaining much. It seems to be doing great now though.

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I have made a couple of the gutted plenums in the past.. here is some good reading on the subject.

 

Here is the graph..

graph1.GIF

 

And the link to the whole writeup..

 

 

CLICKY

 

Made this unit a couple years ago.. gutted maxima intake.

 

101_0487800x600.jpg

 

000_0002800x600-2.jpg

 

101_0489800x600.jpg

Edited by AK9849cy

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Nice intake. :aok:

 

I bookmarked that link a long time ago and forgot to read it, good read for sure.

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