EdSales

So I bought a 96 Civic DX for my Wife. 2 Years later, she calls me and says its missfiring. I've spent the last 3 months trying to diagnose the missfire and have gotten no where.

When you start the car, it runs fine. However, after a minute or 2, when your driving it at low rpm underload, it will missfire till you get to 3K RPMs, then run fine, but it only does this in 2nd through 5th Gear, never in 1st. After 4-5 minutes, it will start to do it in 1st Gear. Another 7 to 8 Minutes, it'll start doing it till 4K RPMs. After another 7 to 8 Minutes, it'll start to missfire at idle. and to 4.5K RPMs.

Code's came up as Front O2 Sensor, Rear O2 Sensor, and Random Missfire Cyclinder 1. I replaced the Rear O2 Sensor, can't do the front because previous owner put in aftermarket Headers. I also replaced Spark Plugs, Plug Wire, Rotor Cap, Ignition Coil, and Distrubtor Cap.

It still was acting up, so, whlie the car was running, I pulled the Injector Clips to each Injector. When I pulled the Injector Clip to Cyclinder 1, the car acted the same. The car bogged down when I pulled the others.

I then replaced the Injector in Cyclinder 1, as well as the Injector Seals, and put another set of Spark Plugs in. Now, the car does not even start. It may be the firing order, as for some reason I have seen 3 different firing orders for Civics on Honda-Tech, but I currently have it set to the one in the FAQ. To also add, the green plastic bit at the bottom of the injector I installed was cracked, but do not see why this would stop the car from even starting now.

I am at a complete loss. I've put alot of money and time into this car, and it goes form Misfiring to now not even starting.

Any help would be greatly appreciated.

Former User

Is there bright white spark at all 4 plugs?

Do all 4 injector clips have battery voltage with the key in ON(II)?

Does the fuel pump prime?

What CEL codes are currently recovered from the ECU?

A bad secondary O2 sensor would not cause misfires as it serves only an emissions function.

kyden

why can't you replace the front o2?

HondaPartsHero

What do you mean you can't change the front 02 sensor?

copy

Hi,
I had an american car with just one O2 sensor bad and it misfired.
I would say this may be the reason.
If you cant get to that sensor, call shops and get estimates telling them about the
after market headers. It used to be that cars would run great with emissions controls disabled , but now they depend on feedback or the control modules wont make the right decisions.
good luck

EdSales

I can't replace the Front O2 Sensor, as the previous owner put an aftermarkhet header in it, and then welded the Front Bunge shut. Do not ask me why someone would do that, but he did.

I'm going to put the firing order the way RonJ has posted as I know thats not how it is now.

I have yet to check spark on each plug.

All 4 Injectors Clips have battery voltage with Ingition On, forgot to mention that.

Fuel Pump does prime.

I have a Cel Code for Front O2 Sensor and Random Missfire Cyclinder 1.

I also would like to mention I ran a Compression Test, and the numbers were with 4 from the lowest to the highest.

d15bvtechatch

iTrader: (2)

you said it runs smooth at times? that rules out internal damage such as a #1 valve etc. try running the front O2 wiring to your second O2.swap injector one with another.

Former User

After you install the wires in the correct firing order, then unplug the primary O2 sensor to see whether the engine will start. If not, check spark at all 4 plugs.


What were the actual numbers?

EdSales

I just used RonJ's firing order and the car started up. However, all the problems that I mentioned above remain. Missfires till about 3K RPMs and then it runs fine.

Codes pulled by jumping the harness were 41 and 65.

EdSales

Forgot to mention, while car was running I pulled the Injector at Cyclinder 1 and it bogged, so that part is fixed.

Acutall numbers were 161, 164, 164, 165.

Former User

Codes 41 and 65 - Check whether 7.5A dash fuse 15 is blown.

Also unplug the primary O2 sensor to see whether the misfire problem is eliminated.

EdSales

Fuse 15 is good. There is no O2 Sensor plugged into the primary spot. I just tried plugging the Rear O2 Sensor into the Primary O2 Sensor spot, but still the same problem.

The O2 Sensor I bought was a Bosch, going to check to see that it was wired up correctly since it has to be cut and spliced into the harness.

Former User

Sounds like the secondary O2 sensor is just not wired up correctly, but that's not your problem. You do need a working primary O2 sensor eventually, but in the meantime, test your new coil and ICM, and also inspect the plugs, wires, cap, and rotor.

EGyoke

I was guessing this as well. With ICMs going bad, it will cause this on any car. Ive had the same thing happen in my Audi and Honda and it was the ICM or MAF that caused the misfires.

Safety_Driver

What spark plugs do you have?
Are they Bosch too?

I would never put anything Bosch to a Japanese car.
Use NGK or Denso!

EdSales

The Spark Plugs are NGK V-Powered.

I fixed the Rear O2 Sensor, and its wired into the Primary O2 Sensor to trick the ECU.

Still have the same problems though. Going to look into the ICM.

copy

Sometimes when the icm go bad, they do not go bad all the way and will work sometimes ,but not all the times,and misfires the engine as one of the other posters said. I think I recall a cheat you can try. If the module is accessible try packing it in cold packs, and driving it around to recreate the problem. If it stops missing then you know it's the problem. The cold makes the icm temporarily work. The diagnostic codes don't necessary tell you the module is failing.

beecee18

do not put boosch platinum plugs,
i know thats prolly not whats in there,
but those plugs blast missfire codes on all makes and models.

92lxsleeper

dont use platinum whatsoever in these cars. stick with NGK coppers

EdSales

Update - Replaced the ICM, the same issues persist. Pretty tired of dealing with the same issue over and over.

Former User

Wherever possible, use a less expensive strategy of testing and inspecting components rather than just replacing.