Upgrade to PRW-2 Ign. Control Module (Power Transistor Unit)

  • Parker
    Parker
    Senior Member
    • 966

    #46
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    Careless wrote: As stated in the original post, michaelp tipped me off about it, but he never posted about it. You can all thank him, credit where it's due.

    I got one for free from a parted out sentra with a GA16 that my old landlord took to pieces. Another member posted about it a long time ago and said it improved idle/ignition response, but his PM to me was not as simple as "flip two wires", which is really all that is required aside from using the bracket or making a new one.

    michaelp mentioned that along with my distributor, I should attempt the swap- and it's given my car new life (along with the distributor). So I thought I would post it.
    Sorry man, I guess I skimmed over that part.

    I'm imagining some bored Z31 evil genius going through every component of the ignition/intake/powertrain/exhaust and determining where the weakest link is, upgrading there, then determining the new weakest link, upgrade THERE, etc. I guess it's not always that organized, and more of a "hey, this part is compatible so let's try it there and see if it improves anything" trial-and-error process. It makes sense I guess, since that's how we evolve. Now I'm wondering how many VG3x's have been sacrificed to the God of Performance Gains in the name of "this fits, let's see if it works." :-D

    Anyhoo, thanks for reposting the info, and thanks to michaelp for the original find!
    Zoey - 1987 Z31T GLL - HKS EVC / CM SS 3" turbo-back / Stance GR+
    Black Betty - 2014 Audi C7 S6 APR1
  • Careless
    Careless
    Senior Member
    • 13279

    #47
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    The simplicity in the discovery of this modification is thanks to Nissan as well.

    On a fuel pump circuit, they will show you + and - terminals with a "F" in the middle for "Fuel Pump" or something.

    On the PTU circuit for both the Z31 and Pathfinder, it shows the Collector, Base, and Emitter terminals for the transistor inside the unit, so figuring out which wires to swap was fairly easy when both diagrams were oriented in the same viewing direction. I would say that there are many other things in the FSM that are quite as easy, but they are not as well detailed internally as the PTU diags are.
  • michaelp
    michaelp
    Senior Member
    • 9384

    #48
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    distortionfile was the name of the person on here who told me about this years ago…and I didn't believe it until I tried it myself. The ONLY reason he did it is because he had a pathfinder one and needed a PTU....
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • Careless
    Careless
    Senior Member
    • 13279

    #49
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    michaelp wrote: distortionfile was the name of the person on here who told me about this years ago…and I didn't believe it until I tried it myself. The ONLY reason he did it is because he had a pathfinder one and needed a PTU....
    riiiiiight. thats who sent it to me too. meh. he should have posted.
  • Dave-D
    Dave-D
    Senior Member
    • 397

    #50
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    Just ordered one off of e-bay as well. Interested to see if it makes a difference…

    My car just doesn't seem to want to start in the morning (ALWAYS on the second crank, fine the rest of the day) and it has a slight lope at idle.
    Also hoping to see an increase in pep on take off (But is is a NA so I'm being realistic on my hopes for that one) HaHa! :lol:
    Black 1985 na/coupe brought back from the dead.
    2000 frontier for work.
    2004 PT Cruiser for gettin' grocery's.
  • michaelp
    michaelp
    Senior Member
    • 9384

    #51
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    Dave-D wrote: Just ordered one off of e-bay as well. Interested to see if it makes a difference…

    My car just doesn't seem to want to start in the morning (ALWAYS on the second crank, fine the rest of the day) and it has a slight lope at idle.
    Also hoping to see an increase in pep on take off (But is is a NA so I'm being realistic on my hopes for that one) HaHa! :lol:
    The cranking and idling issue is more likely the CHTS than anything else.
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • Dave-D
    Dave-D
    Senior Member
    • 397

    #52
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    [quote]michaelp wrote:
    Originally posted by Dave-D
    Just ordered one off of e-bay as well. Interested to see if it makes a difference…

    My car just doesn't seem to want to start in the morning (ALWAYS on the second crank, fine the rest of the day) and it has a slight lope at idle.
    Also hoping to see an increase in pep on take off (But is is a NA so I'm being realistic on my hopes for that one) HaHa! :lol:
    The cranking and idling issue is more likely the CHTS than anything else.
    I have installed a new CHTS and Subharness from Nissan and it did make a huge difference But I still have a small cold start issue
    Black 1985 na/coupe brought back from the dead.
    2000 frontier for work.
    2004 PT Cruiser for gettin' grocery's.
  • michaelp
    michaelp
    Senior Member
    • 9384

    #53
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    [quote]Dave-D wrote: [quote=michaelp]
    Originally posted by Dave-D:13rdk6a1
    Just ordered one off of e-bay as well. Interested to see if it makes a difference…

    My car just doesn't seem to want to start in the morning (ALWAYS on the second crank, fine the rest of the day) and it has a slight lope at idle.
    Also hoping to see an increase in pep on take off (But is is a NA so I'm being realistic on my hopes for that one) HaHa! :lol:
    The cranking and idling issue is more likely the CHTS than anything else.
    I have installed a new CHTS and Subharness from Nissan and it did make a huge difference But I still have a small cold start issue[/quote:13rdk6a1]

    84-85 ECUs have issues with that, get a 87NA ECU.
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • Careless
    Careless
    Senior Member
    • 13279

    #54
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    take this CHTS discussion to PM's.
    this is a PTU installation how-to.
  • edicer2
    edicer2
    Ant Eater
    • 2262

    #55
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    I did it on my 86na will post pics soon…also used the old ptu bracket and mounting location.
    86 NA
    87 Turbo
    Member of the "zetto sun-ichi" group


    Local MN car forum/club anyone welcome..... fivezeroseven.net join!
  • Kutakino
    Kutakino
    Senior Member
    • 585

    #56
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    Just got mine installed and mounted. I wasn't having much luck with the pin, as it kept bending instead of prying on the pin retainer. I had much better luck with one of those super tiny flathead screwdrivers for eyeglasses and such. Very easy to do though, I zip-tied mine to my un-used AIV bracket (the one with the three holes), the holes in the PRW-2 almost line up with the 2 holes that are furthest apart, so it sits nice and snug.

    As far as results, I have a more stable cold-start idle, less bumpiness and no threatening to stall anymore. Immediately noticed quicker throttle response, and there's less popping as it comes down from revving. It feels like there's a little more power now, but that could just be wishful thinking. The idle is smoother driving around town as well. Overall, I think the results definitely justify the very small amount of time and money that goes into this mod.


    86T GLL
  • Dave-D
    Dave-D
    Senior Member
    • 397

    #57
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    OK mine came in the mail from the e-bay seller mentioned earlier in the thread..That was really fast.

    I had a difficult time getting the pin to release the wires so instead I cut and spliced the two wires to each other. (green to black and black to green). Soldiered them and heat shrunk each wire and then wrapped them all in electrical tape to be covered in a short bit of wire loom. All said a 5 minute job..after the soldiering gun heated up.

    I also zipped it to that three hole empty Bracket on the fender....

    The results....
    Well the car fired right up and ran fine no noticeable difference around the neighborhood. It might be a bit more peppy, but it could also be my imagination, so I will have to wait and see if there's a difference tomorrow morning on a cold start and a day of driving around town.

    EDIT: Fired up this morning just a bit easier than normal. She usually starts on the second crank. Today she started on the first. But it could be a fluke, she also felt "peppier" today but again that's not really a very scientific observation, and it is only one day of observation. She did seem to idle smoother, the digital dash will fluctuate between 8k and 9k when sitting in traffic takes about a minute or so to see it happen. Today she sat pretty consistently at 8k. So is it making a difference? I don't know yet. But for the $16 I paid for the part its not like I'm worried about it. I also filled up today so we will see if it makes a difference in the MPGs as well.
    Black 1985 na/coupe brought back from the dead.
    2000 frontier for work.
    2004 PT Cruiser for gettin' grocery's.
  • Z_Karma
    Z_Karma
    Administrator
    • 3318

    #58
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    Sticky this.

    I installed one just now in my black 84T and noticed some of the benefits others have mentioned.
    Noticeably smoother operation at low speeds like when cruising in 2nd through the residential
    areas was the big thing. Normally it's kind of "lurchy" and i'd either coast or keep the RPM's up in 2nd gear.


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • Careless
    Careless
    Senior Member
    • 13279

    #59
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    i took my car out for a rip and to scare the neighbours yesterday. it definitely runs a lot better with this module and my refreshed 88T distributor.

    upon flooring it up the street near the park, two middle-aged gents walked to the side of the road and awaited my return, so i floored it again on the way back and monitored my AFR's. it was around 12.5 under boost and the car was livid! and i heard a "wheeeeeeeeewwww wheeeeee!" from one of those doods. LULZ.

    if i had a camera man, i woulda recorded it, but i does not has :-(
  • biggz31
    biggz31
    Senior Member
    • 208

    #60
    Re: Upgrade to PRW-2 Ign. Control Module (Power Transistor U

    http://www.ebay.com/itm/220419917329?ss … 1438.l2648

    low price power transistor