Performing Honda K24a3/AST5 6spd Conversion

Discussion in 'Workshop Forum' started by lookforjoe, Aug 11, 2019.

  1. lookforjoe

    lookforjoe True Classic

    Hey Dom thanks for the suggestion. The plan is indeed to add intermediary connector(s) as needed. I have a range of Yazaki, Junior Power Timer and Sumitomo connectors that I pillaged from various Volvo installs, and have a stock of new terminals in the various styles & pin sizes - sealed, unsealed, 060, 090, 187 series that I plan on using. I was leanign toward sealed connectors, just in case of water egress but decided that that was unneccesary for the location the connectors will be placed.

    I got the relays wired today, and the two connectors to allow it to be unplugged & removed as a unit

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    6 pin Sumitomo TS 090 for the signal wires & 6 pin JPT for the power/ground feeds
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    Have to figure out where some of the wires need to go that aren't part of the ECU "E" & EMS C201 connectors. Tomorrow I'll get the other relay box that lives in the spare well that feeds the starter & the Bay fan circuits wired. Need to do the same & have it removable with about 2' of harness coming off it. Much easier to do this part at my dining table than squatting in the freezing garage :)
     
    Last edited: Jan 5, 2020
  2. lookforjoe

    lookforjoe True Classic

    Worked on the spare well area relay box. Right now, it's for the starter relay & bay fan circuit. I wired 2 of the spare fuses to constant (30) and the other two to switched (15) for future use.

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    Constant (30) feed for the starter relay & two of the spares. 2pole connector is for the starter feed. Took me forever to decide what type of connector to use, kept vacilating between design types. These are Sumitomo 6.3mm series, somewhat beefier construction than standard old school Yakazi terminals. Going to use Yazaki & Sumitomo 060 terminals & housings for the EMS connections to wiring to ECU "E" & C201 connections.

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    left the spare relays switched power & output/ ground lines out, since I don't know just yet what they will be controlling

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    Diodes inside the insulated strips for ground & switched power, to prevent backfeeding in the bay fan / timer circuitry. Use part of a zip tie to keep the diode connections rigid.

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    About 30 wires left to connect to their appropriate circuits. I've done all I can of the wiring out of the car, time to go back out in the cold garage :(

    EDIT: forgot to note that in figuring out the relay wiring, Honda uses a later convention for the (mostly) Panasonic(?) style relays they use - terminals are numbered 1-5, instead of the older 30, 87, 87a, 86, 85 that I am more used to with Volvo schematics. I have been using the following conversion: 1= 30 2=87 3=85 4=86 (4=87a 5=85 on their 5pole diagrams, which is annoying) based on my read of the Honda schematics. The relays they depict don't seem to utilize the diode I am used to seeing between 3-4 to prevent backfeeds.

    Most all the (Volvo supplied) relays I use are the standard cube with the diode in place. As such, it is essential to make sure the ground side of the circuit is always connected to 85, since the diode is set to prevent current passing from 85 through the coil winding to 86.

    I have noticed some of the Honda-swap schematics wire their relays with 85 as the switched current, and 86 as the ground leg so I have to be careful when following these to switch mine to 85.

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    Last edited: Jan 5, 2020
  3. Hi Hussein,

    (as you probably already know) the diodes that are integrated into some relays (flyback diodes) are there to discharge the voltage spike that occurs when the field in the coil collapses (when the driving power is removed). They are there to protect the circuit that is driving the relay. Many modern applications integrate the protection diode in the actual device which is powering the relay, which is why they might be missing in your relays. Whether or not they are required really depends on the driving circuit (i.e. whether it already includes a flyback diode and / or whether the circuit is sensitive to voltage spikes).

    Anyway, good to see you have thought about adding them. Their absence is the kind of thing that may not create a problem immediately but at some point of time in the future.

    Best regards,
    Dominic.
     
    lookforjoe likes this.
  4. lookforjoe

    lookforjoe True Classic

    Hey Dominic. Thank you for the clarification - I hadn't considered the fact that newer components would incorporate the diodes previously included in the relays. I did not know the primary purpose was regarding voltage spikes. I used them specifically because the bay fan timer circuit did backfeed without the additional diodes, so I figured better safe than sorry.

    Added another relay to the trunk relay box for AC clutch engagement. Not sure I can use the ECU AC Clutch relay & fan relay signals. Looks like the setup uses CANbus signals from the HVAC control head to switch those two signals to ground for relay engagement. Just going to wire it using the original AC clutch feed as switched power to the relay, in case I can figure out a way to use the EMS grounding later on.

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    Worked a little on the ECU fan install.

    Noctua fan mounted low where I can reach behind to press the cover in place. I'll clean up & paint this panel once all the prep work is done.

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    Duct will attach to a soft tube that will fit between the inner & outer fenders. 1.375" is about the max OD I can squeeze through the space in there.

    Duct needs to go through about inline with the top of the vacuum reservoir, that's following the inner wheel arch seam in the trunk. Have to make some sort of retainer for the duct cover (cut from an floor air duct off the S40 AWD parts car) where it fits over the motor.

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    Last edited: Jan 7, 2020
  5. lookforjoe

    lookforjoe True Classic

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    plastic-welding the duct support - outside - the vapors really smells bad

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    I have about 3" depth at the bottom corner in the well

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    primed and painted the bracket

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    EPDM hose I bought from McMasterCarr years ago

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    Hose will go through the inner fender gap to the gas tank side opening & will attach up top

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    gap (parts car) that the hose has to push through

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    Fan

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    PWM controller

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    finished duct plate - lips on the left & bottom to clip it in place.

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    top of plate tucks under vacuum cannister support bracket

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    Attached Files:

    Last edited: Jan 8, 2020
    kmead likes this.
  6. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    Yes!!! Extreme over-engineering. Keep the inlet of your tube pointing down-ish so you don't get water making its way in there.
     
    kmead and lookforjoe like this.
  7. lookforjoe

    lookforjoe True Classic

    plugging away at the electrical wiring - laying out the EMS harness now that I have the various connections figured out. I made an bridge harness (using the pigtail that came with the motor) between the ECU E, C201, relay box and EMS, so that everything can be unplugged if/when the drivetrain requires removal.

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    Now it's mostly just a question of connecting all the dots. AMP JPT connectors for much of this, simply because I have them & they can carry reasonable load. Using Yazaki 1.5 & 2.8 for sensors, signal wires, etc. that don't have the same load requirements.

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    15 to relay box, 15 & 31 for ECU fan and Fuel pump here
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    AC compressor clutch feed
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    ECU fan PWM connection HX 040 series
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    I really prefer these Yakazi 2.8 series terminals & housings (Many on my C30) to the AMP JPT - but they are very hard to come by. Surprising, since so much of the car is FoMoCo, I would have thought they would have been easier to locate.

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    Also putting a couple layers latex on the backside of the remaining Bertone floor mat (that came with the car) to help hold it together & create a rubberized layer. Adheres nicely into the mesh grid on the back. Now I wish I had kept the DS mat - I might have been able to save it with this method. Just need it to last another year or so until I'm ready to install the new carpeting & mats from Henk.

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    Last edited: Jan 19, 2020
  8. lookforjoe

    lookforjoe True Classic

    Got some more of the EMS harness connected - these are all the signal/trigger wires that pass from theater-engine EMS harness through to the cabin via two connectors at that end. I bought these crimpers from Cycle Terminal back when I was doing the C30 AWD swap - to take care of the wiring needs for that.

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    There are issues - I found that I had incorrectly connected a wire on the cabin side of this harness - the one I need for the bay fan thermoswitch I mistakenly connected to the wire intended for the ACfan trigger - which runs all the way to the fusebox instead of terminating in the spare well. I'll have to switch some wires around in the cabin-side connector to address that. Thankfully it's just the that pair.

    This stuff takes me forever. I've been spending days on making the wiring charts listing the different connectors and all the wiring on each side of every connector. I have to do it multiple ways so I can cross-check each wire as I actually connect it to the appropriate housing. Very time consuming for me. I tend to get dyslexic with this stuff & switch pin numbers/locations in my head or look at the housings from the wrong side when counting pin numbers. The convention seems to be pins are numbered starting top row left, viewed from the wire side of the housing. Some of the sketches I made, I had labelled them viewed from the terminal side or from the male housing, which throws everything off (case in point, the sketch in my previous post). Fortunately I figured most of that out on paper rather than after doing the wiring itself.

    I've also been mulling over whether or not to include the ELD (Electronic Load Detection) circuit Honda builds into the EMS. The ECU controls Alt output based on a load signal from that. If I didn't include it, I would still have to figure out a way to 'fool' it otherwise. I chopped up the Acura fusebox & removed the section that houses the input battery/starter/alt cable attachment, with the ELD module. I considered mounting it in the spare well, which would have been easier, however the unit needs to monitor load before any consumers, or it won't operate correctly, based on what I've read about it.

    I bent the left tab flat & cut off some extra material to leave two flats I could drill for studs

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    ELD module I/O to be addressed. For the trigger, I'm going to use the wire I had intended for the acfanrelay, since I've already run that from the trunk through to the Fiat fuse panel, so an easy extension out to the frunk from there. Other two are just switched power & ground.

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    it will go between the battery cable & my inline fuse
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    looks like it will be OK. Will need some sort off insulation/isolation on the underside of the left left for safety.

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    I shoved the duct hose into the inner fender, and found that the most I can get is about 14" forward - there is an reinforcing member below the targa sail that intersects with the inner fender & blocks further passage. Should be OK, still will be drawing air coming from either the gas tank well side opening or from the targa sail vent, I reckon

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    Last edited: Jan 11, 2020
    kmead likes this.
  9. motoTrooper

    motoTrooper True Classic

    Just bombed through your build thread Hussein, awesome thorough, thoughtful fabrication.
     
    lookforjoe likes this.
  10. lookforjoe

    lookforjoe True Classic

    Thank you :)

    The latex seems to be working for fixing the mat backing.

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    It's holding the frayed edging nicely.
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    Found I hadn't discarded the driver's mat, so I'm going to try the same for that. I'll add reinforcing webbing to the damaged sections of the backing, and laminate that into the backing.

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    Test fitting the CEIKA brakes.

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    problem is the calipers won't clear either wheel style without 24mm spacing. I need them to redo the brackets and the hubrings to push the calipers back 12mm. I can deal with 12mm spacers, that won't mess with the wheel arch /fender clearance.

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    Last edited: Jan 20, 2020
    nichol01 likes this.
  11. lookforjoe

    lookforjoe True Classic

    Worked on the EMS wiring after that. Finished the final connections to the harness. The I/O for the reverse lights & brake input were the last

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    putting it all in place
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    bracket, vacuum reservoir & ECU fan ducting secured

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    ECU in

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    Relay box in
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    Much wiring stuffed into this corner
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    Soon I'll get to this mess. That and the ELD circuit, and I should be done with wiring!
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    On the ELD circuit - on the Acura, it doesn't include the starter circuit. I'm wondering if I will have issues with that. Don't know what the impact of that load draw would mean to the ELD's adjustment on the alternator output. I may have to wire the circuit feed to a source that is not active whilst cranking. I have no way of isolating the starter feed.

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    Last edited: Jan 12, 2020
  12. lookforjoe

    lookforjoe True Classic

    Worked on figuring out exactly what needs to be altered with the BBK. 14mm pushback on the rotor hub, with the bracket moved to the backside of the spindle mount - with that I can get away with 12mm spacer for the wheel, which works for both style wheels.

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    bracket needs caliper mount holes moved 4mm outward, with bracket mounted inboard. I cut 4mm off the inboard side to achieve that with the existing mount

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    rotor still clears the balljoint & steering arms on the spindle

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    Caliper clears the wheels with 10mm spacing, I can live with that.

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    After that I installed the ELD unit (still have to wire the module) and worked on the spare well relay box & wiring

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    added the ground circuit junction

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    Last edited: Jan 13, 2020
  13. lookforjoe

    lookforjoe True Classic

    Finished the 8 pole spade bridge connector

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    only the OBDII port left now.

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    ELD circuit wired to this point. Just need to figure out a feed that is not live in crank

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    reconnected the battery - nothing caught fire or turned itself on, so it's looking good - so much wiring I wasn't sure I wouldn't have an issue

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    reverse lights are fed from the ECU, they work

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    Only thing I see is that I have the trigger for the ECU fan connected to (30) feed instead of (15) - it's not supposed to be live with key off.

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    Have to get some gasoline, check the fluids, and then crank it over & see what's what :)
     
  14. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    wait... what did I miss here Hussein? did you enable the stock speedometer and bertone tach with your K20 conversion? I want that action. will need to review your previous posts...

    Cheers. -Darin
     
  15. kmead

    kmead Over half way.

    Location:
    Michigan
    Great news. Not letting the smoke escape is a huge win with all that wiring.

    Looking forward to a startup video.

    Sadly just in time for winter to actually startup again :(
     
  16. lookforjoe

    lookforjoe True Classic

    Hey Darin

    I had already converted my speedo to electronic for the LH2.4 conversion - I used a later Fiat speedo with the stock face. I didn't think the tach signal would be anything special - did I miss something there?

    Yeah, once you let that smoke out, it's all over for most electronics :D

    Not sure I want to run it in the garage, especially 1st startup - likely to be quite the mess. I may have to wait. I still need to do the clutch master & rewire the various add on gauge mess, and relocate the window switches in the center console, so I can try to exercise some patience on that front.

    We are looking at a large storm this coming weekend, I'm told.
     
  17. kmead

    kmead Over half way.

    Location:
    Michigan

    Waiting is likely a good choice. Taking the opportunity to recheck things, do a dry run up of the oil system and so on are all worth while.

    Once it is running it will be hard to put the horse back in the barn and you might be tempted to let things just be. OK that would be me, clearly not you :)
     
    lookforjoe likes this.
  18. lookforjoe

    lookforjoe True Classic

    It was warm today - almost 50ºF - so I opened up the garage, put some gas in the tank & cranked it over (I had previously cranked the motor). I found that the relays are not switching - no main or coil relay, and therefore no fuel pump relay.

    Both the Main and coil relays are supposed to ground via ECU E7, then the pump relay grounds via ECU E17.

    I'm not sure where to start fault tracing for this. Don't know what to check with the ECU in terms of power inputs to confirm basic ECU switching.

    Couldn't find a PGM-FI fault tracing guide, maybe I just don't know where to look for it.

    I'm assuming worst case is that the ECU I bought is dead. :(

    Posted on the K20org forum.
     
  19. rx1900

    rx1900 1981 X1/9


    Hey Hussein. Are you using a stock Honda ECU ?? Does it have an immobilizer circuit ? Have you bypassed it properly ?? That would account for your symptoms.......
     
  20. lookforjoe

    lookforjoe True Classic

    It is a Honda ECU with a K-Tuner chip. I don't know how to check for immobilizer circuit bypass - I'll have to research that. It does make sense though.
     

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