Honda-Tech - Honda Forum Discussion - Honda CRX / EF Civic (1988 - 1991)

o2 sensor issues

EF_MF — Sun, 31 May 2026 02:28:41 GMT

I�ve had my 89 base EF hatchback for awhile and the whole time I�ve had it it hasn�t had an upstream o2 sensor wired in. I rebuilt the engine and I want it to run better so I don�t have to rebuild this d15b1 a second time but I can NOT find a replacement harness plug for the o2 sensor anywhere I�ve been looking and looking and I have a replacement o2 sensor with a connector attached already but I just need to find the harness connector now so I can wire it in and be done with it. Any help on the topic would be greatly appreciated

🙏

1990 CRX ED9 D16Z5 OBD1 - no spark after timing belt replacement + RPM cut at 4500rpm

Jacob6002 — Sat, 23 May 2026 16:16:07 GMT

Hey guys, looking for some help with my 1990 Honda CRX ED9 D16Z5.
Build specs:
� D16Z5 1.6L DOHC, engine rebuilt (rings, seals, head porting)
� Heinrich Tuning aggressive camshafts
� BLOX adjustable cam gears (set to non-factory timing for tune)
� OBD1 conversion
� EMG tune (dohcvtec.pl) with launch control (~4500-5000rpm) and shift light
� L3 gearbox short final drive FD 4.4
� Exedy clutch, lightweight flywheel

History of problems:
1. After first mechanic visit (clutch, wheel bearing, brake pads, fluids) - car started hitting a wall at 4500-5000rpm cannot go above those RpM�s, CEL comes on, loses power but then I can rev past it. After restart CEL clears and same thing happens again.
2. I replaced the distributor with a new one (turned out to be cheap quality) - car ran better, CEL gone, but RPM issue remained.
3. Second mechanic replaced timing belt, water pump, tensioner, seals, spark plugs, oil. Now car cranks but won�t start at all ( I went for a drive about 5-10 minutes my car stalled when I was reversing). No spark. Put old distributor back in - still no start.

Any help appreciated, this car means a lot to me and I want to get it sorted properly.
Thanks

B16A 88 CRX si limp mode

Bseries_Mace — Tue, 19 May 2026 20:17:42 GMT

before the swap with D16A6 as I would give throttle, the throttle would randomly cut out and I wouldn't have any throttle for a period of time, then would cut back in and work fine. This last year I have swapped it to a B16A with a JDM P30 from a EG SIR. This swap was previously in a 90 EF dx. Had the engine and has a rywire engine harness, had to wire the fan to the coolant temp sensor. also have lots of new parts in it. not sure where I should go from here, so any guidance would help. The B16A has no power and seems like its in limp mode, once i drive it it is very hard to get rpm up. After driving it the idle drops and idles around 500 rpm, cuts out but not as much when I had stock engine it it. thanks all.

NEWBIE HERE

2001civic321 — Tue, 19 May 2026 01:06:09 GMT

i have a 1989 civic mfpi swap that i�m chasing down dying a idle after putting in neutral to slow down issue and have some questions. i�m wanting to check the pcv valve and have a hose that goes from intake to the blue pcv valve (pictured) then into the black box on the back passenger side of the motor. it sounds fine when i shake it but i also have these 2 other plugs threaded straight into my engine block. from what i see the one with only one wire going to it is the pcv and if it is why would i have 2? also wondering what the other thing is. any help is appreciated

CRX Rear Bumper Bar

Turbo Dan — Wed, 13 May 2026 04:16:51 GMT

On a modern car this would be a 30 minute bolt on affair, but for a CRX this is a build thread, lol.
Time to do something I've been fearing for many years, the dreaded rear CRX bumper of rust!

I made sure I had a replacement in hand well before I began this job because I knew that once you remove the OEM bumper there is a 0.3% chance it will ever be usable again, and this was definitely the case for me.
- a few screws at each wheel well corner, and mud flaps, this was the only easy part
- 12mm long head nuts, 2 inside the hatch area and 2 below behind a plastic splash shield that you also have to remove by unscrewing the plastic trim screws.
- several philips screws, 3 or so on the top under where the tail light area would be, 2 on the bottom of the bumper, and one dead center behind the license plate
for the philips screws I had to just grab them with channel locks and turn little at a time, or drill out completely.

Finally the bumper ejects itself from the plastic bumper cover and rust explodes all over the garage floor.

I found new-old-stock licence plate brackets on ebay but they were 100USD each plus 20 shipping so 220 total, but I found a universal plastic plate holder on amazon for about $14 next day shipped.
Lighter, cheaper, it'll last longer so I was sold.
I just need to source some stainless hardware for the plate cover and we're good.

The rear body where the rear bumper bolts up to has some rust, but it's not bad. Once I grind off the rust, coat with epoxy primer it should be fine, there's no holes or major structural issues.

This is part 1

1989 civic stalling problem

2001civic321 — Tue, 12 May 2026 01:37:50 GMT

first time user here and don�t really know how to work this so sorry if it�s been posted before! I just bought a 89 sedan with the d15b and the mfpi swap was already done and supposedly has 90k og miles. i drove it 2 hours home and it drove great except for about 1 hour into the drive it died when i was rolling to a stop but started right back up again. the day after i drove to church and it drove fine and then on my home home it died multiple times but restarted everytime. it�s still dying but now it�s taking quite a while to start back up. when i start it after not driving for a long time it�ll start instantly but it seems like when it gets hot it does it more and takes longer to start. any help is appreciated

1991 EF sedan seat brackets

ohanahuichubbz — Thu, 07 May 2026 06:40:43 GMT

Need help finding seat brackets for my 1991 EF sedan EX. Im trying to fit old school Recaro LXs however im having a hard time finding brackets that are specific to 4-door sedan EF model.

heres what i found

https://www.ebay.com/itm/38520873620...3ABFBM2rmdksBn

https://www.ebay.com/itm/38520873601...Bk9SR9q5nZLAZw

These are JDM ef sedan specific but im not sure if theyre direct fit for USDM ef sedan

https://www.carid.com/cipher/auto-se...ls-description

also found these which say sedan specific and theyre located here in USA

https://corbeau.com/products/honda-c...kets-1990-1991

these are also sedan specific, however only fit Corbeau seats.

I have already tried fitting CRX 88-91 Sparco brackets & 88-89 civic HB sparco brackets and they both dont fit at all.

any insight or knowledge is appreciated. Thanks

91 EF Hatch Drum Brakes

Ryoma_04 — Wed, 06 May 2026 14:50:30 GMT

Does anyone know of a tool to get the top spring that goes to the 2 drum shoes on any easier. I've spent a whole day trying to do 1 drum brake and about half of that was me trying to get the top spring on. I've tried needle nose pliers, screw drivers, and a spring pliers that people swore up and down it would make it easy and the pliers don't go far enough. Anyone have any tips or tricks that might help.

Temp/Fuel gauges failed together?

PNW_TurboCRX — Mon, 04 May 2026 05:25:29 GMT

I was driving and watched both my temperature and fuel gauges go from where they were all the way down to the bottom and they�ve never worked again. I�ve replaced the fuse for the gauge cluster with no luck.

Also at the same time, my wipers stopped working.

Any suggestions where to start? At this point I�ve thought of going with an aftermarket water temp gauge, but would prefer if I could get the gauges in the cluster to work again�

Any and all advice is greatly appreciated. Thanks in advance gents.

PFA my crx

Ef hatch in limp mode

lucasef — Mon, 04 May 2026 03:59:16 GMT

My d15b2 in my ef hatch seems to be in limp mode won�t rev past 3500 rpms and cuts fuel. before going into limp mode it was having inconsistent misfires the only code that appeared was code 1 for a 02 sensor also my dizzy is new any ideas of what it may be?