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Abdul's k24 or k20 Swap build/Guide with Complete Wiring diagrams

193229 Views 136 Replies 23 Participants Last post by  Nivek
Hello there, this is about swapping a k24 or k20 in a Crz. In this swap a k24a2/a3 is being swapped. Purpose to do a K24 swap is that it is a lot cheaper than k20 and has more torque and is at 200 Hp and has very much potential to go up in Hp range very easily, plus is boost friendly as it has 10.5:1 CR.
Until recently ( Nov 18,2017) HAsport only made mounts of K-swap(k20 only) for either Civic Si(k20z3) transmissions or DC5 ones which added to swap cost as they are very expensive. If you were to use a k24 block, you would still need a k20z3 or a K20 DC5/RSX-S transmissions. But now HAsport makes mounts for CRZ which support k24 transmissions (TSX 6 spd, Civic si 2012-2015).So now a complete k24 swap can be done in very less $$$$
Now presenting the video series which contains many new things,covers both k24 & k20 route.Also covers Zf1 & Zf2 aswell as Fit GE(2nd Gen) and Fit GK(3rd Gen).

Complete k swap guide part1
Estimated Project cost will be 4500-5000$.(Can go up depending upon labor of shop). This will be very feasible alternative to SC or Turbo kits available for Crz which cost from 3000-5000$
k24a2/a3 with 6 spd manual transmission 1500$-2000$
Shifter & cables= 150$|Model:Civic&hash=item41d02b4fe4:g:GeEAAOSwYyxZf5NL
HAsport Mounts for k24 (now they make them) 700$ (You have to mention k24 and its transmission type when placing order)
Flashpro/Ktuner: 700$/450$
Axles: 500$(HAsport crz for k24, tell them to ship the k24 ones as the k24 half shaft is longer than k20 )
Or you can buy Insane shaft axles which are rated for 500 hp ,I contacted them and they got data of axles from Hasport (Thanks Brian for sharing data for our sake).So now you can get those in 350$ instead of HAsport 500$ and more strong also than HAsport.
It has come into my information that stock k20z half shaft and axles are bolt ons. This engine comes in Civic Fd1(Malaysia) or you can search which alternate version internationally.
I have tried Insaneshaft axles in my Fit and both axles did't fit. So kindly contact Insaneshafts before buying that if axles dont fit they will return them back and refund you.

K20 idler pulley optional: 40$(If k24 have hydraulic Power Steering pump pulley and you don’t want to use that, just disconnected the hydraulic PS lines but keep the pump and pulley there for belt sake, will save you Idler pulley as well as new serpentine belt cost)).but will require a slight modification in power steering pump so that it doesn’t get jammed running without any oil in it.
Civic Si wiring: 120$
Si ECU+ Ignition key Optional =190$( not needed if you can tow your car to Honda dealership and match the new ECU with your old CRZ keys
Custom 2-2.5” exhaust=??
Headers OEM k24
Civic Si primary O2 sensor(Or you can use CRZ one,Yes it was done in a swap in Zf2 chassis in Malaysia and it worked) =120$
Secondary o2 sensor=Optional.
Radiator OEM (its more than enough, we have three k20,s and two 24 running with OEM crz radiators and are just fine, temperature remains 90-94 C.
Misc=IAT sensor, wiring grips (If you don’t want to use your Crz one’s)=50$,coolant 4L,oil etc
Spark plugs can use the ones that come with engine(k24 or k20,BKR7EIX) but I advise new: 35$
Tune: you can use any base TSX/Si map given in Flashpro calibrations
Honda dealership matching of your new immobilizer key and civic Si ecu=50$ ?
Intake: Can use that comes with new engine or just a short ram with K&N filter =50$
Swap shop labor if you don’t have engine stand=? 400-500$ ??(shops here cost 120$ for whole engine swap)
The purpose of this thread is to do almost all work as D.I.Y and at end if you don’t have engine stand to put the engine in/out than you can go to a shop to put engine in just in few hours.
As labor is not so cheap in some countries and they cost per hour bases, so purpose of this build is to get most work done before going to workshop for final engine swap.

Some of you may know me for my Honda Fit Hybrid k20 swap.
Here it is.
It had same LEA Mf6 engine of a CRZ and the wiring of it was copied from a k20 swap crz but was never documented in detail. To date the wiring of CRZ k20 is difficult but it is about to become real easy.
In Pakistan first k20 Crz wiring was done by electrician M.Anwar in 2013. It took him near 2 months to do so as at that time very little support was there about the swaps in modern OBDII cars, yet a hybrid. The fist CRZ was done using two ecu method. The OEM k20a ecu using kpro and a crz ecu.
2nd crz was done by using single ecu of Civic Si USA(2007-11). This method is superior as it has functional OBDII port and the gauge cluster, ABS etc works. Still no documentation was done.
3rd was my car.
here is the thread about its swap
Although I wanted to document the wiring in detail in that build but I failed to do so because it was really complex and i was a beginner in this field.
At that time I promised to myself that I will document it so that its easy enough to do as D.I.Y and the one doing swap is prepared for what is required and what problems he will/might face, like AC compressor hitting chassis and break booster hitting the engine, Radiator fans hitting the intake manifold etc. If you have an automatic CRZ than don’t worry either because I will document all the method from CVT to a manual conversion and it very easy because even in a manual crz you will have to use the new shifter of civic si/tsx and cables. so only thing remains for a cvt is to add a used clutch paddle from a Honda CRZ/Fit/jazz/City/Civic along with its respective cylinder. Conversion will not cost more than 200-300$.
So with no further delay lets start
In the name of Allah, the Most Gracious, the Most Merciful

English is not my language so I apologize for any spelling and grammar mistakes.

Special thanks to Mr.Anwar and Ustad Danish who helped me when I needed.
Here is crz I bought recently for the project. Its a 2010 MT.

Here is the k24 engine for swap

This thread will mainly focus on doing all the work prior to engine installation into engine bay. Goal is to swap k20/24 in just few hours.
There are some sensor grips and main wiring grip you need to buy. Its better if you have a junk yard nearby. If you want to use a k24, than you will have to change oil pressure sending unit, Knock sensor grip, Crank sensor grip.(All these can be used of your Crz engine, but if you plan to return your crz to stock in future and don’t want to use any of its parts than you will have to find these from a junkyard or ebay etc). You will need IAT sensor and its grip.(The crz uses MAF sensor which has IAT sensor integrated into it ,so you will have to buy it, I will give its details in sensor wiring section)
As JDM models don’t have Hill assist so at this time we don’t know if it poses any problem in a k20 swap crz which has it.
I will cover each section of build separately but emphasizing most on how to do wiring on your own.

Here are the link to quick navigate to the pages..
Sensors sweap and sensors wiring connectors modification and engine preperation depending upon engine Page 1
The new forum format has changed the page numbering so much.

Break booster,oil pump,HAsport mounts and instructions Page 2
Engine preperation,clutch,flywheel installation etc etc Page 3
Alternator and starter wiring,immoblizer,pinouts etc Page 4
Main wiring,vss wiring,O2 sensor wiring etc etc Page 5
Axles, halfshaft,Shifters and calble, engine swap and fuel lines and their adapter sizes, some wiring Page 6
Exhaust and gearbox modification Page7
Turbo k24 Sidewinder CRZ build Page 7 & 8
Page 9:
Turbo feed,retun,oil pan modification,fuel pump,fuel injecotrs(FIC 1000cc)
Page 10 The Return Fuel setup,FPR and Fuel Lines

I also have updated Dropbox folder regarding all the offline save of this build upto page 7 of this build.I advise download and save a copy of that becasue some time pictures get deleted from hosting sites.
Dropbox folder
Diagrams and pics
Select option 'Download" on top right corner and it will download as a Zip file.extract and open.its 128 mb download uptill now.
For motivation i have made a collection of videos.Enjoy ;)
Now presenting the Complete K-Swap guide in video series.
All the routes,k24 or k20 in a Honda CR-Z Zf1 chassis aswell as Zf2
Honda Fit Hybrid,Honda Fit GE,Fit GK or in modern Honda.
Save the money and labour.Learn to do it with yourself.
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Throttle bodies

Meanwhile Original Recaro Seats arrived for The K-RZ( Present)

Back to build (Past)
As CRz is drive by wire throttle(DBW),so prefer the engine who has DBW throttle body like a k24a2/3. For those who dont know the differnce.DBW TB have an enlectronic grip on them

Drive by cable have some spring mechanism on which cable attaches

As you are aiming for performace now instead of economy,its better to upgrade throttle body. If engine did't came with DBW than you can buy RX8 throttle body from ebay,its 75 mm and is very cheap than K-tuned 70 mm Throttle body. Both will require an adapter plate made to fit them onto intake manifold.For those who wondering OEM TSX k24a2 is 64mm,some say 62mm.

These pics are from my Honda Fit k20 swap which is using k20 with Rx8 throttle body.Two wiere in throttle body grip also need re-positioned in thee grip,very easy.

On the k24 crz i am using OEM DBW throttle body for now.later on plan to use RX8 one.I also have by passed the coolant ports of throttle body as i live in a warm country.(Pakistan)
So this again reminds when choosing an engine, have a look at its throttle body and prefer the ones who have DBW throttle body.
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A detour

Ok guys we are nearing the wiring section of this build.Remebr the three main goals of this thread
1: Budget build
2:Most things to a as D.I.Y to save the labor
3:Do all the wiring on your own
Before we go to main build to like to take you guys to a de-tour. than we will return to main story. There is very important lesson to be learnt in it.
The thing happned to me that i bought the engine online. The engine looked very clean on outside in pics

My mistake that i should have asked the guy to remove valve cover and show me inside pics.So thats the main lesson i want to convey to you people when buying engine. When i opened valve cover to do valve adjustments,look what i saw

Seems that this engine was sitting for years. Upon opening valve cover the oil sludge was so thick and solid on cams and other parts. i tied to clean it with every thing i got and lot of elbow grease but no success. I asked advice from and they all suggested i change the head.
Buy changing head meant i had to remove crank pulley (nighmare to do,see some videos online people trying) ,i had to buy new head gasket, new head bolts(Honda OEm are one time use only becasue they strach when tighten,some advice to measure them for the strech,but i did't want to take risk,so i used new ARp bolts instead).and ofcourse the whole new head i wil have to buy. So my mistake costed me near 700$-800$ plus a lot of worked had to be done,i mean a lot.You will see in the pics.
A simple checking method of inside of engine is to remove oil cap and look inside.This my CRz engine,look how clean the insides are

Yet it is dirty from outside

A more accurate method is to ask seller to remove valve cover and send pics.but again he can send pics of a diffenret clean engine to you.So its a tricky buy and most important in this swap. If you buy a good engine and pay slightly more it will save you many more $$$.

Again the stuff about to be discussed and shown is fairly advanced.Do not freak out,its totally optional as well. Depends upon which engine you buy.
Ok lets start tearing it down

To open cranck pulley,i locked the flywheel with a thick metal plate and two screws. One screw is tight to flywheel,other is free in the hole

With flywheel locked,i used a long breaker bar and an extention bar/cheater bar on crack fulley bolt using 19 mm socket,while two men were holding engine stable.

After the pulley was defeated,crank case opned.Note that all scrrews are not same lenght,Try to label them etc

After removing old head,i cleaned cylender walls with a thin sand paper and wd40

Some times the residue on wall is not visible,so feel with your fingers. and some time there is pigmentation on walls but no residue. again feeling with your fingers tell you. Dont over do the cleaning with sand paper or you will disturb the engine hone

After cleaning cylender wall,i washed the coolant pathways. Pouring water from one side and on exit side i used a pipe and tub to not make a mess on floor(already messed up :p)

time to install the new ARP head studs with ARP lube

1st hand tight them using an allen key,than use a Good torque wrench to tight them in specific pattern listed online.

Placing new head gasket

New engine head cleaned and ready to go

Dont forget to clean under side of it

Head placed over the engine block.

Dont forget these two dowel pins to place here for perfect head allingment

Make sure its well seated from all sides before tighening the bolts to studs

I think this post is getting too long.i will continue in next
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VTC gear

Again a reminder that above and down posts are Optional.
Head studs tightened according to diagram

All these patterns are easy available online.The cams holders also have removal as well as tightening sequence.

AS you know k24's have 25 degree VTC gear just like our CRZ have.k20's have 50 degree. So why not modify the VTC gear when we are at it.(gains of 25-30 hp)

You will need a hex key set to open it up.only four bolts

k24 dont make power past 45 degree,and piston to wall contact danger is more with full 50 degree.Hondata also recommends to modify k24's to 45 degree. to open it up you will need to detach it from cams. There are thorugh aricles online on this topic.i will just show you some of pics when i modified it.
Opened the inside with hex key set

Dpnt freak out.its not so hard to do,and is optional

Look at the extra metal we need to shave off.Left is k20,right is k24

Hondata recommendation of shaving metal in milimeters.i hope you have vernier calliper and a marker.

You will need to take it to a machine shop to shave of metal or you can use grinder by placing it in a vice to hold it stady.
After all is done,close it
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....Seems that this engine was sitting for years. Upon opening valve cover the oil sludge was so thick and solid on cams and other parts. i tied to clean it with every thing i got and lot of elbow grease but no success. ....
Do machine shops not do hot-tanking anymore?

When I worked industrial inspection, we had a vapor tank- some gallons of carbon tetra-chloride in a 6' square tank about 6' deep. It was probably around a couple hundred degrees, creating a fog up to about a foot from the top. When you put something cool in there, the carbon tet would condense on it and rain off, and things came out so clean you'd not believe it. But like so many once-trusted chemicals, I don't think carbon tet is available anymore- at least not in California, where we can't even get licorice.
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I never seen a dirty head like this before, but on a bright side, it's a good opportunity for k20a head frank.
Do machine shops not do hot-tanking anymore?
Yes they do,but not in my city.Its a small city. Another reason i did most work myself was mechanics and electrictions here dont know about these swaps.i just needed a shop who can just put the engine on stand and drop it in car.
And when i saw such dirty head i was worried about the rest of engine,thats why i went with idea of opening it up and see insides myself and clean them up.
I never seen a dirty head like this before said:
As my plan is to supercharge it so flow of head does't matter much,as blower will positively displace the air into engine.but good suggestion for those who are swapping it for NA power.
Back to build.
Preparing rocker assebmly to be placed on head.So much fun guys.I am glad the head was dirty or i wont have learnt so much.i was just a noob.Thanks to the online stuff on, clubrsx and and many more.

Some people try to hold it togather tighty with their hand to avoid faling off the springs but i used zip ties temporarily to held togather it when lifting from floor and placing it to head

Dont worry if it seperated or fall out,easy to put back

Posting these so that you people dont have to go online and search this stuff.
The head bolts tighened according to torque specs.if i remeber 82 or 92. A good torque wrench is vital.

The head has been build with supertech valvetrain to handle the boost of supercharger

Lubing the place where cams will rotate,any assembly lube or simple engine oil will also work. If you intend to install engine soon than use oil,if engine will be lying for some time,its better to use assmebly lube as it will stay longer where it need to be.All this lubrication to prevent 1st engine startup dry.

Cams placed over rocker assembly and lubed

cam holder have a lable on them,easy to remeber the order which they go in

Torqing the cam holder screws according to pattern

The removal pattern is differnt.
Again bad luck,the torque wrench didt click on one bold and i broken it inside the engine block :(

I searched online,some said one screw broken is ok. If i needed it removed i had to remove whole head,which meant using a new head gasket too.120$ plus it will take 20-30 days to ship to Pakistan. So i took whole engine to local machine shop who have got very talented men. They welded a metal rod with broken screw and extracted it from same hole it broke in :)(Yaaay we got some serious talent in Pakistan ).
Next installing the timing chain and get it proper timed.You can find stuff online how to do.i will quickly show some pics

Meanwhile locking timing chain tensioner with a pin

You will have to struggle here :p

Getting one click out of TCT
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Did you replace the crank bearings?

Btw, please bear with my dumbness, Let's say if I lose the marking on cam pulley against the crank's, how should I align the timing back?
Did you replace the crank bearings?

Btw, please bear with my dumbness, Let's say if I lose the marking on cam pulley against the crank's, how should I align the timing back?
No i didn’t touch the bottom end of engine .crank, pistons, rods etc were ok.
About your question, those markings do help but if you loose them ,no big deal. I lost them too when my timing chain skipped a tooth on crank pulley. but Honda has clear markings over crack pulley as well as cams and timing chain too. Very simple to do. Allign these two on the block and crack

Allign the markings on cams and chain.For k24,the mark of cam should be between the timing chain link as mine below. On k20 the mark shoul be under a link

But easier if two people doing because cams tend to fall out of timing if not held. Its tricky if some one do not want to open crank case and crank pulley. for example of some one only swaps cams. Than some recommend a bungee cord to hold timing chain tight so that it doest slack and jump a teeth at crank pulley. I did try that method but my chain skipped t tooth on crank, so I learned that you need a lot tension in that bungee cord to hold chain tight while you swap cams. Many nice videos on youtube etc etc on this topic of swapping k-series cams.

Looking now at pics,i remember how much i enjoyed working on the engine.
A tip: When you are cleaning engine,be sure to block/cover the head studs holes as that no debrie would enter,otherwise the head bolts will be not properly seated and head will lift and allow coolant and oil to mix.not good. In pic below i have used old head bolts to cover the holes.When engine was cleaned,i removed and used ARP bolts

Some torque specs
K20/24 Torque Specs
* Tire Lug Nuts 80 ft/lbs
* 12mm top nut (1) 33ft/lbs
* 10mm Strut tower Flange Bolts (3) 33 ft/lbs
* 16mm damper pinch bolts (2) 115ft/lbs
* 10mm tie rod nut (1) 32ft/lbs
* brake hose bracket (1) 16ft/lbs
* wheel sensor harness bracket (1) 7.2ft/lbs
* Axle nut 134 ft/lbs

* 10mm top nut 22ft/lbs
* 10mm strut tower top nuts (2) 43ft/lbs
* 12mm damper bottom bolt 45ft/lbs

Rear Camber Arm
* 12mm outer bolt 43ft/lbs
* 12mm inner bolt (2) 43ft/lbs
* 8mm wheel sensor harness bracket 16ft/lbs

Rear Tie Bar
* 12mm inner bolt 43ft/lbs

* 10mm top end link bolt [to bar] 28ft/lbs
* 10mm bottom end link bolt [to car] 29ft/lbs
* 10mm bracket bolt (2) 29ft/lbs

* 10mm top end link bolt [to bar] 28ft/lbs
* 10mm bottom end link bolt [to car] 29ft/lbs
* 8mm bracket bolt (2) 16ft/lbs
*Cylinder head bolts: 39Nm (29ft/lbs), 90 deg + 90 deg. (One extra 90 deg on new bolts.)
10,4,2,6,8 <<<Exhaust>>> 1,7,9,5,3
7,5,1,3,9 <<<Intake>>> 4,6,10,8,2
* Main cap bolts: 29Nm (22ft/lbs) and 56 deg.
* Girdle bolts (M8): 22Nm (16ft/lbs).
* Rod bolts: 29Nm (22ft/lbs) and 90 deg.
* Valve adjustment lock nut: 19Nm (14ft/lbs).
* Valve cover bolts: 12Nm (8.7ft/lbs).
* Chain tensioner bolts: 12Nm (8.7ft/lbs).
* Cam holder bolts: M8 22Nm (16ft/lbs), M6 12Nm (8.7ft/lbs).
* Intake Cam Gear: 112Nm (83ft/lbs).
* Exhaust Cam Gear: 69Nm (51ft/lbs).
* Timing chain cover: M6 12Nm (8.7ft/lbs).
* Crank Pulley: 245Nm (181ft/lbs).
* Flywheel: 118Nm (87ft/lbs).
* Spark plugs:23Nm (17ft/lbs).
* Valve Cover (6) 7ft/lbs
* Valve Lock nut 14ft/lbs
* Spark Plugs (4) 17ft/lbs

* Upper Pass engine mount Flange Nut 40 ft/lbs
* Rear Engine Mount 43 ft/lbs
* Front Engine Mount 47 ft/lbs
* Transmission Engine Mount 40 ft/lbs
* 14mm sub frame bolts (4) 76ft/lbs

* Oil Drain Plug: 29ft/lbs (33 ft/lbs Base models and EP3)
* Oil filter: 8.7ft/lbs
* Oil Pan: 8.7ft/lbs

* Drain plug: 29ft*lbs
* Filler plug: 33ft*lbs
* Flywheel cover: 9ft*lbs
* Flywheel: 90ft*lbs
* Pressure Plat/Clutch: 19ft*lbs

* 10mm Header Bolts/Nuts 33 ft/lbs
* 8mm Header to Down pipe spring nut 16 ft/lbs
* 10mm exhaust manifold bracket bolts 33ft/lbs
* O2 sensors 33ft/lbs
* Cat to mid pipe nut 25 ft/lbs

* Main bolt 90 ft/lbs
* Pressure plate 19 ft/lbs
* Step To Surface OEM Spec's .047in AKA..(47 Thousands Of An Inch)

Half shaft three bolts = 29 ft.lbs
Valve cover 7.2 lb/ft

Torue below 12 lb/ft is rather hand tight. Dont try torque wrench on very low torque specs.It will not click and break the screw
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New clucth and flywheel

Now our engine timed,lets clean the Vtec solenoid and vtec pressure switch

Removing vtec solenoid

Vtec pressure switch

Cleaned them with toothbrush and break cleaner.

Those two were totally clogged.Without cleaning those you can imagined my VTEC ever have engaged. These two i recommned cleaning,These are on side of engine.easy to remove and install.
Some time the vtec switch doesn't fully seats,just slight tap with rubber mallet is needed. IF you will tigh the screw without it properly seated,it will break.

Presparing the crank case cover with honda bond.remeber some of its screws are label or mark them before removing

Yaay almost done.Lets install our new Stage 2 clutch and flywheel.:wink2:
The OEm clutch and flywheel was fine but as i intend to supercharge it so i upgraded to Competition Clutch new series stage II clutch with its flywheel

To open up flywheel bolts you will need to hold crank pulley on opposite side with a breaker bar who's other end would be on florr..If you remember we held flywheel when we were removing cranck pulley and also when tighening it.same goes here,just the opposite

Picture below shows no cranck pulley but to show the method to hold it

Dont forget to place pilot bearing in

Acura 22103-PNA-003 Clutch Pilot Bearing 9$ only

Flywheel installed, Bolts tightened to 92lb/ft in zig zag pattern with torque wrench.

You will need star shapped extension key to tighten them.I advice buy a set of these sockets too.

Finally the clutch and pressure plate installed.

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And lets put some effort to detailing :wink2:

I used Rustolium Brake calliper red paint.2000 F heat resistant

Install exhaust aswell as intake manifolts.Ignition coils,spark plugs NGK BKR7EIX or BKR8EIX if you plan to boost it .
Beofre putting valve cover back,read online where to apply Honda bond on some point to avoid leackage of oil. and do valve adjustments according to Honda specs. Youtube has some nice videos on K-series valve adjustments.
You will need a feeler guage.very cheap

Always do when engine is cold.(Not applicable here as the engine is not even swapped yet).

Not difficult at all.This is the best time to do it becasue you have 360 degree access to engine.Hard to do inside hood

Yes it turned out beatiful :smile2: and now we know its not the outside which is as clean as inside and prepared as it should be.that gives peice of mind

Clutch and throttle body covered to prevent dust

Let the monster rest while we prepare the wiring

Engine Belt/Serpentine Belt:

For a k24/k20 hybrid swap using k20 idler pulley the belt will be 7pk-1640.
for a purre k24a2 using k24 hydraulic power steering pulley as seen in initial pages for my build, it will be 7pk-173- or may be 1740.
Later on i swapped that hydaulic power steering pulley with a k20 idler pulley that is smaller in size.(also can be seen in those posts) the belt will be 7pk-1710 or 1720 can also be fiited. So can 1700 but will be tigh.
Here is a good read

But there is no rule of thumb here.because some will delete AC or power stering,so their belt will be different.Similar is the case from where the k24 came from. Some have different crank pulley size. some come from CR-V,some from RDX etc etc.
So while your engine is out,take a thread and wind it around all the pulleys and measure it.that will give you rough idea in mm or inches. Just look that online and order the belt. It must be 7 ribbed belt( 7Pk)

Yesss finally the wiring section is here guys.The main reason posting this build.
I may be busy tomorow and there its is lot to post from wiring point of view.may be i will post after tomorow.
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You're truly doing the lords work.
Agreed, Nivek you're a legend :thumbsup: Keep it coming!
To pull a pilot bearing (or bushing), put a big dab of grease in it, find a socket and extension that just fits in, and a couple taps with a hammer will ease it right out.
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Today i wanted to post the wiring section but the internet will be down for two days.So instead i am doing my CRz headlights customization and converting them to bi-xenons also.At this late hour of night the internet is back for some time,so instead positng swap build here are some of headlight work pics.Still in progress.(this all is in present.The k24 swap was in past,near two months ago)

Trying some ideas,not finalized yet.

Tomorow i will be busy in completing the headlights. Dont worry that all black color will dim the lights.i have converted the to Bi-xenons.Now they dont need reflaction from background to produce light.
On weakend i will post wiring InshaAllah.
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Alternator and Starter wiring

Back to the main engine swapp build. Lets start the wiring.
The wiring we will be using is 06-11 Civic si, part number 32110-RRB-A04 because my CRZ is older than 2013. For CRZ/Fit above 2013 the 13-15 Civic Si wiring should be ordered.
On eBay there are various listings. Some are selling wiring alone and some are selling wiring with charge harness too. Search for good deal and order.
Like this guy selling both. Some time it’s not listed but you will have to look carefully on picture of listing to see if charge harness is included or not

This also is selling both and I think he don’t know himself either: wink2:

Alone charge harness looks like this. Goes like 80$ but as i said earlier you will find good deals on combined.

Always match the part number

As CRZ has alternator/gernerator fuse integrated on battery +ve terminal,so we will make slight change in Civic si charge harness terminal.

Civic si fuse box and alternator wire location

Below is the charge harness which we will modify. Cut the plastic to expose alternator wires.

We will be getting rid of the extra terminal and its wire

We will modify the remaining terminal so that it can fit our CRZ. Just removing extra metal and making a hole in the remainder.

And here is what it will look like on battery +ve terminal

The items used for this
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Starter wire

If you are using k20,no need to modify this, If using k24,you may need to modify.
Picture below shows my k24 starter

It has a rounder terminal cap while the Civic si grip has square shaped grip.

My k24 engine came with its own compolete wiring,so i removed the rubber cover from it and put that on Civic si starter grip.

The extracted terminal is too narrow to fit the k24 starter.So i opened it up from one side to make some room.

Final result.

There are many many ways you can do can just attach wire to a terminal and put it on the starter.

I liked the factory terminal quality so i modified it. Now let see the other end of starter wire. It ends on big rounder terminal covered with red plastic cover.

At this time i did't know that the CRZ battery +ve terminal containing all the fuses can be detached from the starter terminal. So i cut the CRZ starter wire and attached my k-series starter wire after modifying it.

What i did was i cut the rounder terminal with cutter plas and made a hole in it so that it fits the screw on the baterry +ve terminal.

But this is totally not needed. All you need to do is remove this screw and detach CRZ starter terminal( instead of cutting its wire like i did) and attach the Si terminal in its place.Its plug & play.

Again,this can be done in manny ways.You can attach your own fancy terminals etc etc. main purpose is to join starter wire to battery +ve terminal Un-fused.
One last step remains.We modified the starter terminal labelled as '1' . Its other end is labelled'3' in pic below.

The lenght of this wire is very short to reach our main wiring grip.So you will cut this end and add a thick wire to it and attach that wire to the CRZ main wiring grip which i will mention later.

Attach other end here in main crz grip thick green wire(your color may be differnt)

Two joined togather

The starter modification under hood ends here. But the other end of that green wire which is going into driver compartment fuse box,that need to be attached to the ignition wire from ignition switch. Thats is if you want to bypass clucth pedal depressing feature for CRZ starting.(manuals only).

But if you want to keep that feature of pressing clutch pedal when startting CRZ,that you dont need to do anything in fusebox. Instead you will follow HAsport wiring instructions here.

HAsport is talking about this CRZ grip. But the pic is of engine side grip. The other end of this grip (Chassis side) is what maches the colors according to Hasport.I dont know why Honda chnage color of wire from one side of grip to other. This got me lot of confused and i contaced them that they have mentioned wrong color of wires. They answered that the color and wire will match in chassis side of CRZ 124 plug not engine side.
I know guys this is bit confusing but once you have all the things in front of you,than this all will make sense.
Left one is engine side and right one is chassis side or vise versa.i cant remember correctly. but one will match colors with HAsport instruction which i also will share later.
I am removing plastic cover on one grip to expose it

Grip exposed

Its colors matching exactly to wiring instructions about this red wire at position 3.

Fun is that this wire is for refernece only as its part of CRZ wiring whihc we wont be using. Instead you will use the wire which is opposite to this wire.Which in my case blue wire.

I know it can be confusing but we struggled to start the car so i am posting this. We had to give up the color coding and direct hte ignition wires as i mentioned above when joined pink and green wire( not proper way,but does the job).
Dont cut the grip as yet untill all the wiring is complete which will be during swap.The grip i am holding in my hand is CRz 124 grip which i cut when all wiring was complete and to make things clean look.

So this completes our charge harness wiring.knock sensor i already have covered in sensors modification in very earlier posts of this build.

Next remains adding O2 sensor wiring and the main grips wiring and we will proceed with the actual swap into car.
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Lurking on this thread is very interesting and I find alot of respect for you, doing all the work yourself and providing very excellent detailed diy for others, keeping this board alive
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In above post i wanted to add a new method but it wont let me save my edit becoz that post has more than 20 diagrams. Here goes
Alternate Method: There is another method to bypas this. in that you dont need to find the starter relay and this green wire inside.This method i found by user Merle Schnick in youtube video comments. Thanks to him.

If you want to be able to start the car (in neutral) without pressing the clutch, for the reasons you indicated about the clutch moving the crank laterally against the side thrust bearing plates in a k24/k20 engine becasue these were not designed to be started with clutch pressed.
Your Note 2 (from DropBox "CRZ A Plug Conversion Instructions") says to slice (wire together) the depinned ECM A12 wire to the depinned C124 #3 wire, and then the clutch bypass switch will operate "correctly", which means like normal, i.e., that clutch must be depressed to start. Not what I want. So, the depinned ECM A12 is "looking for" a chassis ground to complete the circuit through the starter cut relay, thus energizing the starter cut relay & closing the contacts, and then the +12v (fused 7.5A) from ignition Start position (IGN-III) will flow through the closed relay contacts to C124 #1, which connects to the starter solenoid (and start the engine). So, just wire the depinned A12 to chassis ground? Yes, I know I will need to connect the heavy wire from C124 #1 to the starter solenoid. (ref schematic, in CR-Z 2011-2012 Service Manual, vol.1, pg. 4-4).(but this method is yet to be tested,as of 23-08-22)
Now onto wiring
So before we discuss main wiring,you should have some basic tools with you like , crimping tool,paper cutter,marker,electrical tape,heat shirink connectors, heat shrink rubber tubes,voltmeter with buzzer function.(Uni-T UT33D is good and cheap one, 15$)

buy some wires of verious lenghts in many colors mostly 18-20 guage. for starter wire buy some 12 guage.

Heat shrink butt connectors,these have soldering material in them.No need to solder the wires.just heat with lighter and they work very well. A must buy

For extra insulation,heat shrink rubber sleeves.I put them over the butt connectors for extra insulation.

Civic Si ecu. ECU part : 37820-RRB-A12 A14 is for auto.dont order that nor the A05. The transponder and the ignition key shown down is not needed if you have a good keymatching/immoblizer programming software like Autel, LAunch etc tec and have Honda dealership near which also do the programming.

ECU A,(white) B(Grey) and C (Green) plugs.

Your New Si wiring will have B,C plug which need no change.The A plug will be used of your CRZ wiring.Its simple when you take out CRZ engine its B and C grips will be with the engine. You will be left with ECU A plug under the hood along with its wiring which will need very few changes to be plugged into new Civic si ECU.

You can also order Guages of your choice. I am using Greddy knock offs and they are very accurate and so far working good(for last 3 months)
oil temp,oil pressure,water temperature etc etc
404 page
Because when you will pass other wire from your firewall hole,pass guages sensor wire at that time too.As engine is out of car,very easy to do at that time.
Some basic ECU code read and clear like, ELM 327

Next i will tell you how to modify A-Plug than we will cover main wiring section.
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Wiring Grip A Of CRZ

The wait is over guys.Lets start the main wiring.
1st we will modify the CRZ ECU wiring A grip according to Civic Si Grip A diagram.Make sense right? Because now the ECU being used will be Civic Si,so all wiring need to according to Si and not the CRZ ECU.
Down is the easy table for making changes in CRZ ECU-A plug wiring. The one with 'X' wire are not needed any more and you can remove them. The other need to change the location within this plug.
Do note that CRZ ZF2 and Fit GE and GK have 49 pin ecu plugs not 44. So in those you will use 2013+ Si wiring and ECU.

Now lets learn how to pin and de-pin.
I am holding the ECU-A white plug in my hand.1st you will need to unlock it by pushing a plastic tap.

Now you will need a sharp tool to insert into pin location to lift the pin holding cap. You can use a dental pick, or a safety pin. I took a small flat head screw driver and grinded its tip to make it pointed,


Lift the lock and pull the same pin from opposite side gently.

Yaaaay you have completed plug-A conversion. Now lets modify the B and C plugs..
Just kidding.We dont need to change anything to B and C plugs :smile2: as they are already of Si wiring.
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ECu pinouts CRZ and Si

A very important requirment is to have both CRZ and Si ECU pinouts. The main changes needed are only in CRZ-A plug which i covered in above post. But some time we need to check sensor wire continuety if some sensor is not working.So we should know where that wire is going in ECU. Thats why i am posting these.Print them and keep them with you during the swap.I have shared all the latest pinouts in my dropbox folder.You can see and even download them.It has ZF2 aswell as Fit GE & GK pinouts
1st CRZ ECC/PCM Plug-A

As we dont have to do anything with CRZ B & C plugs so i was not posting them.but the links in this post CR-Z ECU Wiring
are expired so i am posting CRZ-B and C grips also.but again remember we dont need these in this swap
CRZ Grip-B

CRZ Grip-C

Now for Civic Si 2007-11 pinouts.(for guys 2013+ crz they will need 2012-15 Civic Si pinouts,available online,i dont have them).If image seems smaller,right click on it and select 'view image' option

Plug-B (Grey color)


I know they are not so clear.So at end of this build i will share a dropbox folder containing all the neat diagrams and videos. so you can print them.
In next post i will adress the main wiring portion about CRZ 124 and Civic Si plug.That will conclude most of our wiring.and thats the main part which people fail to figure out.
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...(for guys 2013+ crz they will need 2012-15 Civic Si pinouts,available online,i don't have them)...
Yes--that's an important note! Just reposting here to emphasize. :) Thanks for the complete write-up and attention to detail. :thumbsup:
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