My M30 MPFI SWAP

[MY1PATH]

Ok It's been mentioned here and there but I've been asked to put all my m30 mpfi swap info out on the table, it won't be very picture heavy as I go along, but here goes.

 

I am converting my truck from Throttle Body Injection (TBI) to Multi- Port Fuel Injection (MPFI) In layman's terms that means going from 2 injectors to 6 injectors (one for each cylinder, like most modern cars) To do this, I need to change over the entire Intake System, Fuel System and Electrical System. Wanting the best of all worlds in terms of fuel economy, performance and reliability I am planning on mixing and matching the best of parts from 3 different Nissan/Infiniti vehicles...

 

MPFI PATHFINDER INTAKE: The MPFI intake found on 90-95 pathfinders is my best option. It features long intake runners and maintains good intake velocity at low engine speeds while evenly feeding all cylinders. The North West has more pathfinders than any other region so these parts are easy to come by. I can also use the 3.3 upper manifold which features a larger throttle body as well but keep in mind larger throttle bodies make it easier to waste gas unless you are more gentle on the skinny pedal than you were before.

 

INFINITI M30 WITH NISTUNE ELECTRICAL SYSTEM: This is what sets my plan apart from any other MPFI conversion, I am using the complete ECU, harness and sensor array from a 1990 Infiniti M30. THESE ARE VERY RARE. They were considered the brain child of Nissan SOHC ECU's*** and the one of best SOHC ECU candidates to use with NissTune because of the Check Connector laptop tuning interface (NissTune only) This allows user friendly performance and economy tuning as well as ready adaptability to upgrades. (this is not a Mega Squirt battle so shut up*)I think the only ECU better is the z32 ecu.

 

Notes for those wanting to convert an already MPFI to the M30 ECU: I don't think its really worth it, the biggest performance benefit to the M30 ECU is that it runs a higher resolution MAF.

• You will need to re-pin the ECU connector or make an adapter harness out of an old pathy ECU socket and an M30 harness plug. (FSM for both cars can be found at http://www.nicoclub.com/fsm
  
• You may choose to add the A/C cut off wire to the A/C relay which allows the ECU to shut off the AC compressor under heavy acceleration.
  
• You need to use the M30 MAF. This is better than the pathfinder MAF anyway and can work well for 200+hp applications
  
• A Z32 MAF can be used for 300+hp applications BUT ONLY if you are using Nistune otherwise your metering will be off. If you are re-pinning the pathfinder harness the 4 wire MAF has an extra ground; both center pins can be the same wire as long as it goes to both chassis ground and the correct ECU ground pin*** ***
  
• You need to use the M30 Titania o2 sensor OR 89-93 Pathfinder Titania o2 sensor (small bung)The Pathfinder sensor has a longer pigtail and the signal wire and shield are wrong so you must swap the middle pin on the 3way plug with the pin on the one way plug*** * All others are Zirconium and will not work. Zirconium sensors GENERATE their own electricity and can damage Titania sensor based ECU's
  
• If you do not wish to use a fuel temp sensor you need to run a 1.5 kOhm resistor to ground for that wire. A sensor can be added simply by tack welding an m10x1 nut to your fuel rail.
  
• if you keep the variable voltage fuel pump control you SHOULD run a shielded wire from the ECU to the FUEL tank or the 20hz pulsed frequency may interfere with other electronics in the vehicle (stereo, GPS, CB etc...) If you wish to bypass it see the image below for Full Power Fuel Pump...
  
• There is a FPR vacuum solenoid (same as egr solenoid just hooked up to the Fuel Regulator instead) that allows the ECU to raise the Fuel Pressure for faster start ups. This part is optional and no codes or running problems come from leaving it off. (in the end I removed mine, its not such a big deal)
  
• The EGR system and EGR solenoid can be left off in the same fashion BUT ONLY if you have a federal ECU. (CA ECU's require an EGT sensor inside the EGR passage)
  
• Check Connector (Consult) can be cut from the drivers dash panel and wired directly (or extended) from the ECU harness for quick access wherever you want to put it.
  
• The pathfinder throttle switch is wired backwards from the M30. (square plug, the round pigtail one is TPS) Pins A and C need to be swapped.*** ** This will mess with your idle if you don't fix it.
  
• (more notes to come as I think of them)
  

Pathfinder MPFI ECU With NissTune???:The physical layout of the pathfinder board is the almost the same as the M30. They use the same chip with a slightly different program and I believe the Nistune Type II board (same used for M30) will work in a MPFI pathy computer just fine. I will inquire about that when I order one for my M30 ecu.IF NissTUNE can be installed on a Pathfinder ECU then I believe the M30 MAF can be calibrated in for use with the pathfinder...

• (coming soon)
  

Z32 300ZX FUEL SYSTEM**: For now I am using the MPFI pathfinder fuel system 180cc side feed injectors. The original plan was to use 84-89 300ZX Turbo (z31) 270cc top feed injectors but these cars are getting rare and I happened to find something much better. The 270cc z32 Phase 2 injectors found in the 1994+ NA 300zx are ethanol resistant, feature a pintless design and weather resistant lower corrosion connector. That's 3 improvements over the z31 injectors but it gets better... the Phase 2 injectors are side feed and fit in pathy fuel rails. This gives loads of drop in options for flow rates and the 270cc Phase 2 units are found in loads of Nissan cars and are also cheaply bought re-manufactured! So that's what I'll be using once I get Nistune up and running. More

info on the Phase 2 injectors can be found here. http://z32.wikispace...m/Fuel+Injector Do note, the Phase 1 will not fit, I already tried it.

 

 

Full Power Fuel Pump

 

* I have come across many people in real life and on the internet who have told me I could do it better, easier cheaper with mega squirt.

I DON'T CARE! THIS HIS HOW I'M DOING IT! /rant

 

**To preface this I will likely be tuning for e85 at some point to help with smog tests and with gas being at 10% ethanol and possibly rising to 15% I want to be prepared. Ethanol eats older style injectors...To run e85 and sleep well at night I need something more ethanol resistant...

 

*** The were originally favored by the z31 300zx crowd because of the Consult tool capabilities and refinements over the z31 computers that were some times buggy and had injection issues among other things. The m30 uses the injectors sequential fire (one at a time) and then batch fire (all at a time) at Higher RPM but the z31 uses bank fire (1,3,5 and 2,4,6 alternating) and then batch fire at Higer RPM. All that being said, electronically the M30 ECU is really not much greater than the the other vg30e ECU's of the 90's like the Maxima, and Pathfinder.

 

*** * o2 rewire Make sure you use the 89-93 Pathfinder Titania o2 sensor (small bung) if you do this. The advantage is A long Pigtail on the sensor.

 

*** **(pictures of TPS rewire coming)

 

*** *** 3pin to 4pin MAF; (N60 & N62 on the MAF Label) (borrowed from NICO Club)

Edited October 17, 2012 by MY1PATH

[MY1PATH]

More notes;

 

For NA engines the 270cc injectors should support an engine up to 250 HP. For all you 3.3 folks out there this is really good to know because your stock 180cc injectors limit you to about 200HP yes more can be had, (Maybe 225) but this is much exceeding the industry rated duty cycle of 80% and you are essentially pouring the fuel into the engine instead of spraying it in shorter controlled bursts. Upping your injector flow rates to correctly match your HP will allow you to deliver the correct volume of fuel, in a shorter, more controlled amount of time and in a more refined pattern that will not be as wasteful.

Now turbo on the other hand... the Phase 2 370cc from the Twin Turbo 300zx should support you up to 280HP or 300HP if you bump the fuel pressure (like to 50psi)

 

All Flow Rate and HP numbers were based on calculations found on http://www.rceng.com/technical.aspx

Edited July 4, 2012 by MY1PATH

[unccpathfinder]

350 swap cheaper easier faster? I'm just kidding...good @!*% man...I'm looking to do some engine upgrades down the road...so this whole project could be useful...before swapping from tbi to mpfi I wanted to throw the Eaton m90 on...there has been thoughts to do nistune with the 3.3 SC but this just throws more into the mix...keep the updates coming

[Tungsten]

I definitely like the ECU idea with the higher flow rate injectors. The M30 ECU with ethanol resistant next generation 270cc injectors is going to be awesome for those of us running mods and/or VG33E/VG34E swaps. I can't wait to see how this goes for you. Good luck with the tuning.

[MY1PATH]

ok, I lied (twice) firstly the pictures below will help me explain things and second the Phase 2 injectors fit but I would rather keep them in Phase 2 rails. The injector I tried the the first time in the pathy rail was new and I did not push it in all the way because the O-rings are single use and I did not want to crush them. So today when I got my own injectors I got to push them all the way in and find out that the Phase 2 will just barely seat because it has a lip on its top that goes into a counter bore on the Phase 2 rail. So I thought up several solutions.

1. Shave off the lip on the injector--- this will work, the O-ring will go about 3mm deeper into the rail and the lower o-ring will be able to seat more completely.*
   
2. Shave down the rail about 1.5mm---this will work, the O-ring will go about 1.5mm deeper into the rail and the lower o-ring will be able to seat more completely.* But you now have less threads for you O-ring cap. and the Pathy rail is too thin to counter bore so that is out of the question.
   
3. Modify A PHASE 2 rail--- This is best, the injectors get the rail that was designed for them. you will may need to shorten the end of the rail so that it does not stick out too far behind your engine. (cutting and tig welding) and you will need to cut off the mounting tabs and weld new larger ones on in the correct location. Mister 510 MIGHT be able to set this up as a service because he's the one that will be doing the TIG welding for me AND he has a fixture for the lower manifold to setting it up will be easy. You would have to provide him with a phase 2 rail AND a pathfinder rail to combine as cores.
   

*The Pathfinder rail has a slightly larger inside diameter where the lower o-ring seals. So even though 1 and 2 will work with a new lower O-ring, there is no guarantee on the longevity of the lower O-ring seal before it decides to flood your engine.

 

And now for today's pictures. The last one is is just to show off my port work and spacer.

^ FUEL RAIL FITMENT

 

^INJECTOR FITMENT

 

A little tip on removing the vg30DE/DETT fuel rails... look down at the injector clips first, if they have a little metal clip on the plug don't event start pulling it apart, they are the wrong ones.

ONCE you see and unplug all the newer style push button clips remove the center cover, throttle cables and fuel lines. Remove the balance pipe and all wires tied to it. There should be 8 bolts down the center and LAST BUT NOT LEAST a support bracket on each side of the manifold with 2 bolts in it (I did not see these at first and it made things interesting...). Lift the manifold up a few inches and remove the 2 emission pipes screwed in next to the support brackets. Now flip the manifold up and you have access to the rails.

 

 

Edit, I have confirmed that Pathfinder 3.0 and the 3.3 rails found in the quest, xterra, frontier, and qx4 are all the same rails. Below are images of the Phase 2 ethanol resistant (left) injectors and the old Phase 1 (right). Also pictured left is the Sumitomo electrical connector needed to run the Phase 2 injector. So if you want to keep your stock rails and run boost or convert to e85, you can run the ~320cc supercharged xterra injectors.

Edited April 18, 2012 by MY1PATH

[MY1PATH]

I do have one more option up my sleeve that I've been holding back...

VG33ER (supercharged x and fronty) injectors are about 320cc maybe more. They are less common, more expensive but they SHOULD be ethanol resistant since they were introduced after 2001 and they SHOULD drop in as they look physically the same as the 3.3 injectors.

[Inyourface1650]

Subscribed. I want to see how the M30 thing goes,parts are plentiful on ebay, and I want to do the ECM/MAF/O2 swap.

[MY1PATH]

Today I assembled my MPFI conversion in the driveway and spread out the wire harness in the grass. Sitting in the sun I picked through wires and how to run them cleaning up the harness as I go and re-routing things in a way that works better for the Pathy intake.

 

I wired the consult connector directly to the ECU plug and I have Half of the engine bay essentials done; CAS, MAF, IGN coil, IGN module, IGN resistor and Distributor "ground" from IGN resistor. You can see all these in their respective places and estimated routing before bundling on the right. And everything else that's in the lists below is on the left.

That leaves the remaining engine bay essentials; injectors (and new plugs), Idle air control, O2 sensor, Cyl Head Tem, grounds and power to the harness

 

And the following extras; Cold Idle thingy, AC compressor power, AC compressor override from ECU, Fuel TEMP, Coolant temp, Oil PS, Knock sensor, Fan output, AC fan output.

 

And then lastly I have to Re-wire the fuel pump system with fully shielded wire for variable Fuel control, set up a location for the M30 ECU (Hidden above the glove box or on top of the dash.

 

I also found out today that the M30 MAF is much larger than the Pathy MAF and the Pathy Intake hose will not fit over it. So I cut off the end of the pathy hose and cut off the end of the M30 hose. I then stuffed what was left of the pathy hose into the end of the M30 hose until the bellows interlocked. The M30 hose also had a stepped foam ring where its hose steps down to the Throttle body. I spread sealant over the union of my 2 hoses and stretched the stepped foam ring over it. Perfect Fit!

This will work just fine for now. Maybe when I'm running a larger TB and engine I will upgrade the entire tube but as of right now there is no need.

[Pav]

Thanks for sharing your project details...more power to you for taking on this build.

 

Looking forward to seeing the results especially the before and after fuel consumption figures. Best of luck.

[MY1PATH]

Thanks for sharing your project details...more power to you for taking on this build.

 

Looking forward to seeing the results especially the before and after fuel consumption figures. Best of luck.

Fuel consumption is crap, the engine has been cooked a few too many times and flooded a few too many times so my rings are worn out and don't seal till the coolant reaches 200F. If I do enough driving in a day to keep the engine hot it does ok but usually I get to work before the coolant is even 150F.

But yes,hopefully I will see some gains.

 

The M30 was getting about 27mpg hwy but its about 700 lbs lighter the engine(not mine) is in much better shape, its not shaped like a brick (not shaped like a race car either) and it doesn't have mud tires on it.

Edited April 9, 2012 by MY1PATH

[Pav]

Fuel consumption is crap, the engine has been cooked a few too many times and flooded a few too many times so my rings are worn out and don't seal till the coolant reaches 200F. If I do enough driving in a day to keep the engine hot it does ok but usually I get to work before the coolant is even 150F.

But yes,hopefully I will see some gains.

 

The M30 was getting about 27mpg hwy but its about 700 lbs lighter the engine(not mine) is in much better shape, its not shaped like a brick (not shaped like a race car either) and it doesn't have mud tires on it.

 

Holy...that does sound like your mileage can only improve. I'm cheering for you. Looks like you will have some serious gains. Fortunately, my truck was one of the '95s that got recalled and they dropped a new engine in it that is still running smoothly. Even with your 700 extra pounds I'm sure you will be putting up some impressive numbers. I'll let you get back to work...cheers

[MY1PATH]

I think not, the M30 isn't any better than the MPFI Pathfinder as far as engine output. Its just smoother and more NissTune friendly.

Both adapt to mods like, cams and headders better than the TBI does. So Based on adapting to my existing mods and the SMALL fuel injection advantage I plan to pick up 15HP at the very most.

[Kingman]

Nice Garret. When I did mine it felt like I picked up about 10-15HP. Noticeable difference for sure. Love the pics and info on the injectors, good stuff man.

 

Psst. Mine will still sound better

 

Have you looked in to the fuel pump relay mod to get rid of the variable voltage?

[MY1PATH]

Nice Garret. When I did mine it felt like I picked up about 10-15HP. Noticeable difference for sure. Love the pics and info on the injectors, good stuff man.

 

Psst. Mine will still sound better

 

Have you looked in to the fuel pump relay mod to get rid of the variable voltage?

 

Mine sounds like crap, My pipes are rattling on the frame from a hard hit I took on the trail and I just haven't got around to that part of the problem yet...

What's wrong with Variable Voltage? For now I'm leaving it because its easier to keep everything wired the way I found it. I think pathy PUMP and its compatible, I think the internals are the same and the only difference is the attached pickup tube/ strainer.

 

Moving on...

I made More progress today, I shed lots of rock hard and cracking electrical tape and other insulating materials. It seems they did their job for the last 20 years the wires inside are not brittle, only a little stiff near the connectors but since everything's closer on the pathy and I'm replacing most the connectors I get to cut back to nearly fresh wire.

 

Here's my simulated engine bay to keep everything's orientation and allow me to move the project arround as a whole instead of piece by piece.

 

Here's my completed injector wiring, coolant temp, fuel temp and cyl head temp wiring that I completed today. a close up of the Odd numbered bank and even closer on the cool connectors I am using for now.

 

Now I get to move on to running wires for the upper manifold... I'm still waiting on my TPS connector and really all of this should be interesting since the wires will run under the upper and attach to the bottom and sides of the upper. At least its only 4 items and 3 new plugs total...

[MY1PATH]

So, turns out the bolt patter for the MAF is different on the airbox...

so I had to install the M30 Velocity port in the pathy airbox. this vitamin bottle was a tight fit to keep both holes lined up while I drilled the new holes through the port.

then I opened the holes up to 1/2" and hot melt pressed the brass inserts from the M30 box into the pathy box

(no picture yet)

then slipped the velocity port on the inside with some sealant and shot it in with pop-rivets and sealed the heads.

[Leo94]

Just to make sure, You are using a pathfinder MPFI with a M30 ECU? I live in australia so i don't know about this car much but is it similar to the maxima and can a maxima ecu be used. Also can you just use a pathfinder MPFI ecu for a quicker conversion. Would you say that a z31 300zx ecu is better than a m30 or maxima ecu?

Edited April 20, 2012 by Leo94

[MY1PATH]

the z31 ecu is probably the worst ecu to use. they had firing order issues with the injectors and many of them were recalled and hot wired to become bank fire instead of sequential fire. If your looking for easy, pull everything from an MPFI Pathfinder, all the harnesses go the right places and lay right.

 

The M30, early maxima and pathfinder ECU are all very similar in terms of smooth running, idle quality and error free operation.

Simply put, the m30 ECU has more capabilities and is a little more performance friendly when it comes to doing modifications to the engine. (better MAF and programming for that MAF and a tiantia o2 sensor and associated programming)

 

I believe Nistune will do a pathfinder ECU but it would be on a case by case basis. where as the type 2 Nistune board (for m30 and other cars) is part of their line up.

[MY1PATH]

Well I Finally found a wire that is suitable for my variable voltage fuel pump.

http://www.opentip.c...ucts_id=1572727

 

It has to be shielded or the frequency spread across 20ft of wire mess with all kinds of electronics nearby. Think EMP with a 20ft antenna.

 

I was trying to find 14ga shielded single conductor but it doesn't exist (unless I buy like 500 feet or more) or the so I'm using 14ga shielded two conductor and splicing the shield with the extra wire for a stronger connection at the harness. I just wish it was more than just a foil shield.

 

Or I'd rather use this stuff but I'm still waiting on a price...

http://www.awcwire.com/ProductSpec.aspx?id=PTFE-Tape-Wrap

Edited April 23, 2012 by MY1PATH

[Leo94]

Sweet just the answer I was looking for. Having a quick look through a MPFI pathfinder wiring diagram in the EC section i see that some parts labeled "AT" and some "MT" obviously its stating depening on the transmission it might or might not have that circuit but what exactly changes will my pathfinder react different to one with a manual ECU as my pathfinder is manual.

 

Edit: One example is the vehicle speed sensor how would i hook up my one to a ECU from a auto MPFI pathfinder.

Edited April 21, 2012 by Leo94

[MY1PATH]

Well this weekend I wired up the IACV and the IACV-Regulator. The Idle Air Control Valve uses solenoid to open and close a needle valve allowing air to bypass the throttle body and increase the Idle. If there was ever a plug that needed to be changed to push-release It would be this one. If you have tried to unplug it to properly adjust your idle or remove the upper manifold then you know what I'm talking about...

The IACV-Regulator is the tall tower looking thing on the driver side of the manifold near the firewall. It uses a Bi-metal heating element attached to a shutter. when the heating element is cold the shutter is wide open allowing air to bypass the throttle body for high cold idle. When the engine is running the heating element is always on and as it heats up the shutter closes.

 

Attached to the restraining loop for the throttle cable (just left of center in the pic) Is a bracket I made for the Fuel Pressure Regulator Solenoid. It was really the best place I could think to put it. Including this part is optional, just cap off the wires if you don't use it. I used the same Soleniod as the one for the EGR because it routes the hoses a little better.

 

Lastly I ripped all the crazy amount of grounding wires out of the harness and spliced them into two thick 12ga grounding wires. this greatly reduced the bulk of the harness and cleaned it up some.

 

My clutter of un-run wires is much smaller now, I just need to run the EGR, AC controls, and replace the plugs for the CYL HEAD sensor and round TPS PLUG.

Then I can work on power routing to the harness and lining up wires inside the truck to be ready for that. and then I can focus on the very small amount of In-Cab Wiring and ECU mounting...

[MY1PATH]

Well this weekend I wired up the IACV and the IACV-Regulator. The Idle Air Control Valve uses solenoid to open and close a needle valve allowing air to bypass the throttle body and increase the Idle. If there was ever a plug that needed to be changed to push-release It would be this one. If you have tried to unplug it to properly adjust your idle or remove the upper manifold then you know what I'm talking about...

The IACV-Regulator is the tall tower looking thing on the driver side of the manifold near the firewall. It uses a Bi-metal heating element attached to a shutter. when the heating element is cold the shutter is wide open allowing air to bypass the throttle body for high cold idle. When the engine is running the heating element is always on and as it heats up the shutter closes.

 

Attached to the restraining loop for the throttle cable (just left of center in the pic) Is a bracket I made for the Fuel Pressure Regulator Solenoid. It was really the best place I could think to put it. Including this part is optional, just cap off the wires if you don't use it. I used the same Soleniod as the one for the EGR because it routes the hoses a little better.

 

Lastly I ripped all the crazy amount of grounding wires out of the harness and spliced them into two thick 12ga grounding wires. this greatly reduced the bulk of the harness and cleaned it up some.

 

My clutter of un-run wires is much smaller now, I just need to run the EGR, AC controls, and replace the plugs for the CYL HEAD sensor and round TPS PLUG.

Then I can work on power routing to the harness and lining up wires inside the truck to be ready for that. and then I can focus on the very small amount of In-Cab Wiring and ECU mounting...

[krmiller07]

Now I'm starting to get excited to see and hear how it runs, and hopefully the mpg and HP gains will be worth all the extra effort.Thanks for the updates. Your 89 was originally a TBI model before this...correct ?

[MY1PATH]

Yesterday I pulled the TBI ecu and all the wires up from the carpet and pulled the blower box to see where it enters the firewall... Today I modified a glove box to nest the new smaller M30 ECU inside it. This will keep it higher above any water intrusion I might get and also give it ease of access for future purposes.

So the glove box door (color of your interior) and the glove box liner (black) total a little over 1/2" thick in some areas. So I picked the far corner of the glove box and cut the liner the size of the ECU and then shaved down the webbing inside the glove box door in the same area....

 

Now the ECU sits nested about 3/8 deep in the liner.

eventually I want to put the ecu above the glove box. this may take some custom AC ducting or maybe just mounting it up diagonal... I will make a wire frame ECU to show me where it would stick down and where I need to cut to make it work without actually having to cut to get the wire frame in there.

Edited April 25, 2012 by MY1PATH

[MY1PATH]

Finally got My NEW MAF PLUG from down under

and my ECU is fitted to the glove box with harness attached. (not converted, just mounted)

(Pic coming later)

Edited April 26, 2012 by MY1PATH

[MY1PATH]

TBI ECU and wires are no longer in the cab Soon everything TBI will be de-bundled (from lights and starter etc) to a state that I can just Unplug and remove.

Meanwhile I hope to complete the other harness this coming weekend and poke it thought the firewall and re-bundle with the existing [lights, horn, starter] so that it will be ready to plug in and go!

Just a few hard tugs and the ECU came through the firewall!

Edited April 27, 2012 by MY1PATH