I have a 96' civic hatchback cx with a '97 obd2 b18b1 motor/trans. When performing the swap, I replaced several components which include the distributor cap/rotor, spark plug wires, and spark plugs. I also replaced the timing belt (set cam/crank timing correctly), and had a shop set ignition timing to 16 degrees +/- 2 degrees.

I was driving down the freeway the other day and my CEL came on, code 71 (Random Misfire cylinder #1). When I got home, I popped the hood and listened to the motor to try to hear a misfire, but everything was fine. The car runs and drives fine as well.

I tried resetting the ECU and after about ~100 miles of driving the CEL came back on (code 71). I've been trying to research this code and figure out the problem for most people, but having trouble trying to pin point the problem.

Take note that I had to perform the CKF bypass to eliminate the code 54 (FFStech.net). I'm not sure if this could be potentially playing a role.

After checking everything that I have listed, is there anything else that I should be inspecting to further diagnosis this problem? Any help is appreciated,

Thanks!

 

Misfire in cyl 1.

Check for a clogged injector and compression test the cylinders.

 

How could I check if the injector is clogged? Pull the rail and see if there is any sludge around any of the cylinders?

I'll go perform a compression test soon.

 

Just pulled the spark plugs and ran a compression test, here are the results:

Cylinder 1 - 128
Cylinder 2 - 125
Cylinder 3 - 125
Cylinder 4 - 128

This was a dry test, no oil was put in the cylinders while testing.

Going to find a way to check the injectors in a second.

 

Update numero 2:

Used my multimeter to check the resistance for each injector, all of them were around ~12.5 ohms

Next I pulled the fuel rail, all of the injectors had black sludge on them, but I didn't see any visual clogging on the tips of the injectors. Here's a reference pic from the passenger side of the vehicle:



The injector tips should be bright orange shown by injector #1 (I wiped it with a rag before I took the picture), but instead covered with black sludge.

 

With rail removed, crank the engine and compare the fuel spray pattern from inj #1 to the others.

 

I just put everything back and in the garage for now, tomorrow morning I'll pull it off again and check the spray pattern.

Is my compression normal for a B18B1 with ~200k miles?

 

I'm not concerned about the compression numbers.

If the injector spray looks fine, triple check the wire job for the CKF bypass.

 

Thanks Ron, I'll report back tomorrow.

 

Another update,

I just tried to inspect the spray pattern across all four injectors by removing the rail and cranking the engine, but it was hard to see any fuel coming out of the injectors. After a few cranks, injector at cylinder number 1 would pop out and spray me with fuel while all the others stayed in the rail.

I'm about to go check the CKF bypass wiring again.

 

Your injectors may need to be cleaned.

 

I just did a few more tries of inspecting the fuel injectors but failed to see any fuel come out, and after the key was turned off a few of them would push out and squirt fuel everywhere.

Triple checked the CKF wiring and everything is connected properly, but there is a small cut on the C4 (CYP Sensor) wire. The wire isn't severed, but the insulation is cut slightly and some copper wire is being exposed.

Also, I'm using NGK Platinum G-Power spark plugs gapped at .044

The Helms says to gap at .039-.043, would .001 make a difference? (Sorry if this isn't relevant)

 

Did it squirt at the tip or where the injector meets the fuel rail?

 

https://www.injectorrx.com/

Send those suckers off, get them cleaned.

 

Where the injector meets the fuel rail.

Thanks for the reputable link, I also have the option of having them cleaned at a local shop for a family discount



BTW, my friend advised me to double check my spark plug gap, and they were all off by about .008

Used my gapper tool carefully to get them as close to .044 as possible (spec by NGK). Also going to drop in a can of seafoam and reset the ecu to see if this code will GO AWAY.

 

Few days later, dumped in sea foam, gapped plugs correctly, CEL comes back on.

Any advice on where to go from here? Have a shop clean my injectors? Could my CKF wiring mod be causing the problem?

Any input helps, thanks.

 

yes, clean your injectors. seems like a logical place to start

 

Thanks, I'm going to see when I can get that done. I'm worried that it has more to do with my CKF mod though.

 

Then post pictures of the wire mods.

In the meantime, clean the injectors.

 

 

Does the wire splicing meet your expectations?

 

Everything within both quick-splices is firm and connected. There is some copper wire exposed on the CYP power signal wire (yellow) but, at least to me, doesn't seem to be a problem.

It meets my expectations, but I'm not an expert.

 

Might want to have someone crank your car while you hold the rail and fuel injectors with both hands and have spray onto a bunch of cloth.

 

Sounds like a good plan, I'll try another spray test with a few buddies then report back.

 

Alright, I'm reviving this thread because I still have the same problem 8 months later.

CEL Code P0301 - Random Misfire Cylinder 1

Spark Plugs are about ~15k miles old, NGK, spark is white from the wire
Compression is about ~125 psi across the board (throttle closed)
Brand New Fuel filter, fuel pump is priming, and replaced the fuel injector for cylinder 1 with a remanufactured injector from rockauto.com

STILL HAVE AN EFFING CEL, WTF?!

ALSO, the car will sometimes start...then die (in hot weather). (meaning the car turns over, fires up, then dies immediately)

My scan tool says P0301, with the catalyst monitor not completed its cycle after being driving 1000+ miles.

Anybody have any advice on some further troubleshooting? Thank you.