Back by popular demand, a wiring diagram for the obd0 b18a1 in an MPFI 88-91 CRX (that’s HF and Si, not the DX).  This should also apply to EF/ED Civics, but I’m running on memory here and don’t have a car to verify this on.

If there are any questions or corrections (as I’m sure there will be), feel free to leave them in the comments.

Jadkar (John, to some of us) is one of my automotive heroes.  Too few CRX’s receive the love and attention the cars rightfully deserve, and most die deaths of malnutrition and abuse.  He owned a CRX from brand new all the way up to present, and has completely restored and updated it, revitalizing everything from the engine (a supercharged b18c5) to the suspension (powder coating every suspension component) and brakes (with a big brake kit and stainless steel lines) to make the ultimate daily driven CRX.  He also founded tuner-junction, a well-rounded automotive forum that sees light, but high-quality traffic.  Here’s some eye candy of his perfect example of a CRX, but if you’re looking for a bit more check out his CRX gallery.

Driven Daily: What first inspired you to buy a CRX, and how did you get it?
Jadkar:

I always admired Hondas. As a young boy about 6 years of age my Mother’s boyfriend had a early Accord (maybe 83) and I loved the car and til’ this day I don’t know why.  When I was 14 I bought a used 1981 Civic 1300 4spd.  The car was “cute” and that’s about it.  It was slow as hell and I knew from reading that Honda’s CRX was much more what I wanted, still a small hatch but with a hotter engine and much better handling.  When I was alabout 16 I secured a loan with the help of my parents and bought a 1986 red CRX Si.

Driven Daily: How long have you been working on this project?
Jadkar:

I bought my current CRX new when I was a senior in High School and I drove the car until 1996 when I took it off the road and stored it.  I started the rebuild when I took the car out of storage in 2005 and I have been working on it ever since.  You know these things never have an end date, you just get started and keep going.

Driven Daily: If you had to guess, how much of an investment (time and money) have you put into it?
Jadkar:

Well, I bought the car in 1991 for $10,500 and over the years including this past major rebuild I would say I’m a tad over 40K in mods

Driven Daily: If you had to pick, what would you say is your favorite part about your car?
Jadkar:

When the car was stock I liked the styling the best, it was much more ahead of it’s time then anything on the road.  Now that time has elapsed and the rebuild has progressed to what it is I would have to say the drivetrain is my favorite.

Driven Daily: Did you set out with a goal in mind, or just build the car as the pieces came together?

I had a very specific goal.  The whp rose slightly as I was not overly impressed with the na ITR swap but other than that I planned everything out pretty precisely (I had about ten years to do so)

Driven Daily: What would you say the major differences between the US and UK tuning scenes?
Jadkar:

I couldn’t tell you, I don’t follow the tuning scenes very closely.  I have two kids and a hectic schedule, I race in the summer and that’s about as much of the scene that I get and even that isn’t a good judge.  I hang out with hard core track rats not really “tuners” in the sense that you’re refering to.

Driven Daily: You’ve done a few projects in the same chassis.  How many different driveable versions has your CRX seen?
Jadkar:

I would say 4

Driven Daily: If you could change any one thing about the CRX, what would it be?
Jadkar:

I would make it AWD.  The car has way too much power and the front wheels can’t handle it.

Driven Daily: Do you see the upcoming CR-Z as a reinvention of the CRX?
Jadkar:

To an extent yes.  However, Honda needs to get their act together and listen to what the people want.  Many enthusiasts have been screaming for a CRX replacement for a long time and they haven’t been listening.  Just as we have been wanting a RL with a V8 and a real NSX replacement.  Unfortunately, Honda has been making “appliances” for automobiles lately and I’m afraid they will call the new car the CRX replacement but it will be a hybrid or toned down econo-commuter box.

Driven Daily: What are your future plans for this car?
Jadkar:

Keep the fuel system in check and stop it from melting pistons   Actually, nothing.  I need to do some guage work and maybe some rollers but other than that I’m done.  The upkeep from racing every year keeps me busy enough.

Driven Daily: You’ve been tuning other peoples’ cars and powder-coating parts for others for awhile now.  Do you have any plans to go into business doing this?
Jadkar:

Nah, maybe later but not now.  I had my NJ dealer license for a while and I sold it because my full-time job was too time consuming.  I do much much better with my regular job than to try and jeopordize it with the auto stuff.  Later in life when my time gets a little more flexible maybe I will re-visit the auto business.

Driven Daily: What would you consider to be the most important modification a new CRX owner could perform?
Jadkar:

It really depends on what you do with the car.  I think the CRX had two major weaknesses, the engine was not strong enough and the brakes are totally incapable at high speeds.  If you are getting into road racing (legally) I would say learn to drive the car and upgrade the brakes as it will really help.  Plus the temptation to add more whp will get you into trouble if you don’t get some larger binders.  If you’re running 1/4 mile and you’re not too afraid of stopping than go engine.  Use your head though, I’m sure with that big engine you WILL be driving on the road and trust me you WILL NOT stop well.  Good brakes on our car are relativly inexpessive when compared to the engine upgrades so I would say do the brakes first.

I’ve always been a big fan of the CRX HF as a platform to build upon.  It’s lightweight and lacks the extra luxury components from the Si, yet is outfitted with MPFI (multi-point fuel injection) instead of the CRX DX/STD’s DPFI (dual-point fuel injection).  With a little creative swapping, the CRX HF shell can be made into a lighter, more purposeful driving machine than an Si or a DX with less work.

HF Rear Brakes

The stock CRX HF brakes are small, light, easy-to-maintain brakes that suit the stock 1900-lb HF perfectly.  The stock drums do suffer from brake fade as soon as the car is driven moderately roughly, so an upgrade isn’t a bad idea.  The problem is that the trailing arms (which are the parts that your brakes bolt to) are completely different designs.

Si Rear Brakes

The CRX Si rear brakes use a stronger, heavier trailing arm to mount onto.  The whole assembly needs to be swapped for it to work on the CRX HF.

At the end of the day, this setup just makes maintenance simpler and decreases brake fade.

Installation

These images offer a look at the differences in the rear braking system setup between the CRX HF and Si.  The first notable difference is the trailing arms, the part that supports all of the bearing housing and the area that the brakes bolt to are in fact different.  The holes around the si “axle” hold the brake “plate” on, then the caliper covers that and the brake system is complete.  Also, in doing this swap, be aware that the brake lines will be vastly different.  I think the parking brake is shorter on the HF also.

Just for reference know that the lower control arms are also different.  The parts are interchangeable (you can fit SI lca’s on the HF) but the HF lca’s don’t have the hole for the rear sway arm.  If you are switching everything from an SI to HF the sway bar also wont bolt up to the body.  There are holes for it, but they are only empty holes and are not threaded..

I didn’t get as many pictures as I would have liked, so if you do this swap and don’t mind sharing your pictures let me know and I’ll post up more details.

It’s no secret that the first-gen suspension is mushy and leaves much to be desired. The aftermarket suspension for the 84-87 CRX leaves much to be desired as well, so you may think your options end there.

You’d be dead wrong! You simply need to get a little creative with a hybrid setup. First-gen Integra parts are still commonplace as well as third-gen Civic parts.  The second-gen CRX stole the first-gen’s fire, so to speak.

A full rear end can be used from the Integra, which gives the added bonus of rear disks (unless you race heavily, the only difference you’ll notice is the ease of maintenance). The front end of the first-generation CRX is respectable, but the rear really needs lots of suspension love. Focus on stiffening the rear with a strut bar and upgraded sway bar, and if your budget allows, move on to springs and struts.

If possible, search for a full set of matched coilovers or a kit that includes struts. Remember to drive safely, and keep speed on the track.

Tales are told around the campfire on moonless nights about the CRX’s dreaded bitch pin. If you haven’t heard of this terrible monster before, gather ’round and I’ll tell you about it.

There will come a day when you find that your engine must come out of your car, and while your breaker bar will get those motor mounts, and your old rotting rubber hoses can be cut and replaced, the bitch pin is there to stay. Every swap is fraught with danger, but none so great as the bitch pin. It’s an impossible hydra-like beast, meaning every time you hit it it gets stronger and embeds itself further. You may find that perfect punch and a big mini-sledge, but the bitch pin still refuses to move. Never fear, though! This bitch pin has a great weakness to be exploited.

After I had already screwed my bitch pin into a pulp of metal that refused  to move, I looked around on the internet to find that everybody else just whacked it with a hammer.  Eventually it’ll come out, right?

Wrong. Actually, using physics for dynamic pressure and using only enough force to move it is the key. Experimenting with a c-clamp and a wooden dowel yielded positive results, but I came across a better way. This article gives nice pictures and a good walkthrough of what needs to be done:

bitch pin removal

Add this “bitch pin removal kit” to the budget of any swap you tackle.

1. C-clamp
2. sockets (deep and shallow) that fit the bitch pin inside
3. small drill bit set (for putting pressure on the bitch pin itself)

There’s definitely a science to it, but hopefully this will help you work that thing out.

In the 1990′s engine technology took leaps and bounds, and manufacturers began adding advanced engineering principles to all the cars that rolled off their showroom floors.  Small-displacement, highly efficient powerplants were in vogue, with the Honda b16a1 and Toyota’s 4age powering hot hatches all over Japan and Europe.  Even today these engines are sought after as inexpensive ways to produce surprising amounts of power.

The ZC was special because it was a small-displacement 4cylinder motor with aggressively tuned dual overhead camshafts.  It came in the CRX and Civic in the early 90′s, and the very similar d16a8 came to the US in the Acura Integra.  This stocky little beast had excellent transmission options as well with short gear ratios, long gear ratios, and limited slip differentials available.

It is also obd0, making it a simple plug-and-play swap from a previous MPFI engine, and keeping tuning simple and straightforward using PGMFI.  If you have a stock CRX DX, you’ll need to convert the wiring harness to MPFI and use the ZC ecu.

The ZC is one of the more difficult Honda engines to identify, so the folks over at jdmcars put together this pdf:  zc_identification for your reference.  Power output is generally ~130hp with torque to match, and is a very strong candidate for boost with low-compression pistons.  The combination of being inexpensive, efficient, and powerful for its size make this a perfect candidate for a daily driven CRX.

If you’re looking for more info about the ZC, read here:

d-series.org

I’ve been writing a lot about my own project, so today I’m taking a break from updating on that and instead you get to read about one of my all-time favorite engines.

The b16a1 ROCKS.

The b16a1 is the holy grail of CRX motors.  It boasts true vtec, aggressive dual overhead cams, a high safe redline, a lsd-equipped close-ratio cable-driven transmission, and a very tuneable ecu.  It really is as nice a fit for the CRX as Honda ever made.

All b16 motors are good choices because of the aftermarket available and the near-perfect rod/stroke ratio, but the b16a1 is particularly suited to the ED chassis (88-91 CRX and Civics) because it’s obd0 and uses a cable transmission.  If it came from a CRX SiR, the transmission will be LSD-equipped.  If it’s from an Integra XSi, it will come without an LSD.

However, there are downsides.

Because the b16a1 was only available in Japan, and was only produced in the CRX and Civic SiR, getting one requires contacting an importer (who will generally buy one from a running car because of modern Japanese smog restrictions).  You will not know any of the history of the motor, but if the shop is worth spending time on, they will offer a full test run on the engine (dyno run and leakdown test) to ensure that it’s in working condition.

The other problem that arises is finding replacement parts.  The B family of Honda motors benefits from a large aftermarket parts availability, but stock parts are difficult to find because they need to be imported directly.

Final Thoughts

Overall, the b16a1 is a great choice to put in the CRX.  As long as you find a reputable dealer that offers a “complete swap” (axles, ecu, wiring harness, intake manifold, throttle body, exhaust manifold, etc) and the motor and transmission are both in good repair, expect to spend roughly $3,000 USD on this swap, assuming you will be installing it yourself.

More Info

That’s just the beginning.  There is a wealth of information available for the b16 series.  Here’s a good start for your hunt for more:

• Identify a b16
• Ryans CRX (I can’t find Ryan’s original build thread, but droppedcrxsi was one of the best b16a1 writeups I had ever found.  Now this site is a forum, and I haven’t browsed it yet)
• B16a1 Nitty Gritty
• Wikipedia B-series

It’s the most common caveat long-term CRX owners share: we got no love in the cupholder department. If I adjust my passenger’s seat just right, and the stars are aligned, and I never hit a bump, I can keep my Aroma Joe’s coffee cups between the ebrake handle and the seat. That doesn’t quite cut it. Another solution that doesn’t quite cut it is the armrest that came in JDM and EDM EG civics. They’re too expensive and there just aren’t enough to go around for all of us.  All sorts of other terrible attempts to screw, rubber band, or hang cupholders in a crx have cropped up, but none really fit the bill if you ask me.  Three cheap, stock-ish alternatives have cropped up that I have been able to find.

Option 1: Nissan Sentra cupholder

OZ wrote up a nice DIY on using a Sentra cupholder, but this requires cutting into your console.  It’s a moderate amount of work and can’t be undone if you decide you don’t like it or want to resell the car.  Generally speaking, custom irreversible changes aren’t worth doing if there are other options available to you.  Read on.

Option 2: Taurus SHO Cupholder/Coinholder

The Taurus SHO cupholder fits into a DIN slot, so if you don’t mind moving your stereo head somewhere else, you can fit this beastie in there for around $10. If you’re skilled with fabrication, you can cut your own DIN-sized hole and line up the bolts yourself. Also, heater controls use a DIN space, so if you don’t mind leaving your climate just the way it is you can replace that with this cupholder. Here’s how the SHO cupholder fits into a CRX dash:

Option 3: Acura Integra cupholder

Lastly, the 94+ Integra cupholder fits toward the bottom of your center console. This is a clean replacement for the cigarette lighter and ashtray, stays tasteful, and is common/cheap enough for me to recommend. I’ve ordered one of these to replace my current Taurus SHO cupholder, it fit pretty well.  You need to be aware of where your fingers are when shifting into third, though. For further research, check out honda-tech’s forum thread here. If you have any alternative ideas for cupholders in your CRX, leave a comment below!  If you’ve already installed one, send in an email with some pictures  and I’ll feature your car.

The d16z6 and d16y8 amount to the same gains.  Both are economical single-cam true-vtec engines.  Both are common in salvage yards, available in 1992–2000 Civic EX and Si’s, and some models of Del Sol.  Power output is roughly 130hp for each model, but a frankenstein of the two is reputed to work best.  The d16z6 has a better-flowing head and the d16y8 has a better-flowing intake manifold, so putting the two together on top of any d16 block will yield some power gains.

The most notable difference between the two is the onboard diagnostics.  The d16z6 is an obd1 engine, while the d16y8 is an obd2 engine.  Both can be converted to obd0 easily enough, or your wiring harness can be converted to obd1 (obd2 is not recommended for engine tuning other than specific applications). During the wiring harness conversion, the vtec solenoid should be wired into the ECU (automatic ECUs are particularly useful for this modification).

Availability of parts and relative ease of engine installation make both these engines excellent candidates for any CRX.

From time to time, I receive emails asking for help and I generally send an email back to the original sender and consider the matter closed.  Sometimes, these answers to these questions are general enough that others could benefit from seeing the answers, so I’m starting a Reader Mailbag section of the site.  Send in your questions and I’ll publish any questions that could help others.

My name is Eric, I’m Bam’s friend he told you about with the CRX? Anyway, here is the trouble I’m having.  I have a 91 CRX HF shell, that bam had previously swapped the guts into off of his old 91 Si.  When I got the car it had a pretty much dead motor, the car still ran, but it had no compression, so I swapped the motor.  The motor I ended up with is a D15b6 out of a 91 HF.  So the motors in there, and has the correct motor harness, PM8 ECU, connected to the Si’s dash wiring.  Here’s the catch, everything works, except I’m not getting spark?  I have fuel, I have compression, but not spark.  Plugs are new, I’ve tried swapping dizzy’s, ECU’s and checked connections, and can’t seem to find a problem? and am at a loss as to where to look next?  Any help or insight you could give me would be awesome.

Well Eric, there are a few causes that you can check for.  I would go about this by process of elimination.  Systematically eliminate problems in the chain, one component at a time.  Start from the end result and work back until you find the source of the problem.

1. Spark plugs — Inline spark testers are inexpensive and work well, but you can also test them the old-fashioned way.  Unscrew the plug from the engine and put the diode (the end that would go inside the engine) close to bare metal and crank the engine.  If a spark jumps from the diode to the bare metal, the plug is functioning correctly.
2. Spark plug wires — Test spark plug wires with a multimeter or a test light.  Plug one end into a power source and the other end into a test light.  If the light doesn’t turn on you can be relatively sure that the cable is bad and should be replaced.
3. Distributor — The most common malfunction with distributors is a worn cap and rotor, which will prevent spark plugs from receiving electricity that would allow it to create a spark.  It’s also a good idea to make sure your distributor timing is correct (check with your manual) using a timing light (available at most local automotive stores).
4. Ignition Coil — An ignition coil is essentially a capacitor which stores electricity and powers the spark plugs (the distributor just controls when the coil and a spark plug are connected, the coil is the power source).  Most Hondas (including your CRX) use an internal coil, meaning the coil and distributor are one unit.  Since you’ve replaced the distributor (and I’m assuming you tested it to make sure it worked in another car, or bought a remanufactured one that had been tested), you should be in the clear on both the coil and distributor.
5. Fuses — Check the fuse box under the dash, on the driver’s side.  There should be a fuse labeled ‘ignition’.  Is it blown?
6. Relays — Relays are a great idea to put in cars, until you have to start troubleshooting.  The main relay on obd0 cars are notorious for dying on all Hondas, and are generally in terrible locations (close to the fuse box under the driver’s side dash).  There’s a good writeup on tegger.com that discusses them.
7. ECU — Since you’ve already swapped the ECU for another pm8, this is probably not the problem.  Double-check to see if the ECU is throwing any codes (a blinking light on the ECU itself is a good indication).
8. Wiring — If you check everything above, the wiring harness or connectors are most likely at fault.  Since so many CRX owners upgrade to obd1 (or even obd2 in some cases) wiring harnesses are inexpensive online and you should be able to get a replacement without breaking the bank.

I definitely want to know how this turns out, so be sure to update me directly or on the forum (link below).  I hope to hear that this is sorted out and your HF is purring like a kitten soon!