Misfire... *fixed!*

[nickk]

Hey guys, I've been having an unusual problem with my B16a2 EG.

It will idle fine when warming up, and then it has a hectically rough idle when warm, sounds like a massive cam. The revs will hunt, it drops down till it sounds like it will stall, then it jumps back up. Then sometimes it seems like it is idling fine while I'm stopped, then I give the accelerator a little stab and it will idle like sh!t again.

Sometimes it will also misfire. If I'm sitting at the lights and the idle gets very rough, it will misfire and backfire (very loud) when I take off. If I ignore the misfire and push it to VTEC, it cures it. I noticed that it misfires after bit of a squirt. (i.e hit vtec in 1st, 2nd, 3rd... slow down back into 2nd, vtec again in 2nd and 3rd and maybe one more time through 2nd and 3rd after that... then stop for anywhere between 10 seconds to a minute and take off and it misfires.)

I'm planning on cleaning the plugs and checking the TPS voltage but other than that I'm not sure what else it could be. Would it be worth removing the PCV and cleaning it or letting it soak to unblock any gunk that may have built up inside? It didn't have the PCV connected when I purchased the car and I thought that would be the problem. I bought a second hand one and slapped it on without cleaning it.

*edit* I also noticed that the fuel consumption is pretty average for a b16a - 350-400k's per tank, with a few squirts here and there.

It's not throwing any CEL's either... is there any way to check that the CEL is working? haha

*edit* i have a hondata in it too!

[djt]

I have a 96 ek4 and my revs before used to hunt up and down on idle from 1500 down to 1000 and back up and sometimes my idle is at 1300. My mechanic changed my map sensor, this made my idle drop from 1300 down to 700 - 900 but still my idle still hunts up and down between 1500 and 1000 so he changed my idle air control valve (iacv) and it fixed everything. if you down't wanna spend money on it just yet, clean you map/throttle body and your iacv. hope this helps.

oh yeah and my engine light used to come on when im driving which made my car misfire hard, which replacing the map sensor fixes.

[OMG.JAI xD]

Go to your nearest tuner and ask them to plug it into the laptop and read the live data. See if there is anything out of the ordinary.

I was at TODA a few weeks ago and an EG came in with a b16a. Has sort of the same symptoms you did and his one did stall. Though if i didnt mishear the problem, something to do with the ECU. And it was internal.

Though it could be something as simple as the IACV... which is probably the most common word used on ozhonda.

[nickk]

Thanks for the advice, I'll clean up the TB and IACV, do a carbon flush and clean all the plugs and see if there is any change, if not then I'll take it to a tuner.
Is it worth me cleaning the PCV? I'm not sure if it works.

[grifty]

Thanks for the advice, I'll clean up the TB and IACV, do a carbon flush and clean all the plugs and see if there is any change, if not then I'll take it to a tuner.
Is it worth me cleaning the PCV? I'm not sure if it works.

shake the PCV valve up and down, if you hear something rattling inside then it works.

[OMG.JAI xD]

shake the PCV valve up and down, if you hear something rattling inside then it works.

Or start the car and pull the pcv valve out with the vacuum source still connected and put your finger over the bottom hole. Should hear it click as you block and unblock the valve.

Some pvc valves are internally loaded (most likely spring loaded) and only works with vacuum applied, sorta acts as a one way valve.

[nickk]

iacv was dirty, cleaned it very quickly and the idle fixed itself, but I didn't let it dry and the idle is screwed again. probably need to clean it better and let it dry, then do a tb clean!

[nickk]

update.

After cleaning the iacv, idle was sweet for a day... then idle went back to sh!t .
I serviced my car, put NGK bkr6e-11's, changed fuel and oil filters and used fresh oil.
After the service, the car would misfire under load/when i put my foot down. If I crawl to the speed limit, it won't.
Changed to NGK bkr6e plugs, misfire was fixed :D
Decided to do a throttle body clean... after doing so, misfire central once again.

If I take off super slow, it won't misfire. Once I get to speed, if I just coast / light accell, no misfire.
I have had maybe 5/10seconds when it doesn't misfire under load, so I took it to about 8000rpm, back off then it misfires again. It stopped misfiring again when under load for 10 seconds or so, so i decided just to give half throttle and shift gears. As soon as I slowed and tried to accelerate again, misfire.

What I've tried doing last night and today:
I've tried cleaning the plugs, misfire.
I've tried changing the plugs, misfire.
I've checked the leads, zapped myself, misfire.


Things that may be influencing the misfire:

Exhaust manifold leak on cylinder #2 ?

Carbon canister is not plumbed 100%, but that never caused problems previously.

Any ideas guys??

[grifty]

how old are the spark plug leads?

[mocchi]

how did you get zapped from checking leads?

[nickk]

swapped the leads around on both ends.. seems as though its still cylinder 2 misfiring. It was misfiring while idling so i pulled cylinder 2 lead out and it zapped me. leads seem fine, they are fairly new.

[OMG.JAI xD]

Get your spark plug. Bkr6e usually comes pregapped at .9-1.1mm. Re gap your spark plugs to .7=.8mm on all 4. See if that fixes your problem.

If it does. You probably have a dying coil. Or your car was tuned on the hondata for iridium plugs, and changing to a normal tip plug with a tuned gnition timing can explain your unusual misfires/backfiring.


Edit: Also. An ignition lead should not zap you. Unless it has a break in the insulation or you touched the end of it. Check that you dont have a spark leak.

[dahondr98]

I'd suggest that it would probably be a good move to replace all the spark plug/coil high tension leads for new ones. I've had problems before (misfiring at town speeds, but OK at highway speeds) which have been cured by a new set of leads. I've also once suffered the indignity of breaking down near the entrance to an inner city car park (different car), resulting in lots of "help" from irate motorists being held up - a faulty coil lead was the culprit there, and wiggling it finally enabled me to start it and get home. These days, I'd bin the ba****ds as soon as look at them, and replace them with a new set.:angel:

[nickk]

I was holding it at the top of the tube when i got zapped (at the 90 degree bend). When I put NGK BKR6E-11's in 1.1mm gap, it misses almost constantly. When I put a BRK6E's in, it runs better. I might try a new set of leads, just for good measure.

This morning I drove to work and it's misfiring alot less.
Only thing I have done (which was yesterday after work) is re-tap the threads for the headers because two were stripped and there was a slight no. 2 cyl. exhaust leak, sealed up the gasket with some ultra copper silicone and put the headers back on.

It seems like the more I drive it then let it cool, the better it gets. At this stage I'm assuming the T/B clean loosened a sh!t load of carbon and it's still burning it out. Maybe a bit of carbon is causing an exhaust valve to stay slightly open?

[nickk]

update, misfires gone... and i didn't do anything except for give the car a belting as soon as it stopped misfiring and then baby it when it did. Now it is fine... wtf?!

[teh_mechanic]

if you can get your hands on someone else's dizzy to try its pretty likely the problem is in there. I once had a similar misfire problem in mine and i replaced the coil and Ignition Control Module in the dizzy and it fixed it. Most of the time either of this will just straight up die and cause the car to not run, but in my case it was causing a misfire, more at higher rpm. I tried the ICM DIY test on here and it seemed fine. Changed it anyway and yeah it fixed it. I find the internal coil and ICM in b series dizzy (or d series for that matter) to be quite weak and have changed several at work. You can just try to replace one but its advisable to replace both as they work together, or just the whole dizzy if you want to the go the whole way. I'm not saying this is your problem, just that it's likely. And either that or the leads makes the most sense since it runs better on brk6e's which are 8mm gap (arn't they?) rather than the bkr6e-11 11mm gap. Smaller gap is helping the struggling ignition system

[nickk]

misfire has stopped completely now. I got a new set of leads, seems to have made a difference. I put my old set on a mates car and it makes his car detonate when he gives the throttle a stab... weird! Anyway they are in the bin now.
As for the plugs, the -11 means 1.1mm.. I've got mine gapped to around 0.8mm and it seems perfect.

[aaronng]

misfire has stopped completely now. I got a new set of leads, seems to have made a difference. I put my old set on a mates car and it makes his car detonate when he gives the throttle a stab... weird! Anyway they are in the bin now.
As for the plugs, the -11 means 1.1mm.. I've got mine gapped to around 0.8mm and it seems perfect.

If at 1.1mm you get misses and 0.8mm works fine, that means there is not enough potential voltage across the spark plug gap. Since you have changed the leads, does it still miss at 1.1mm? If it does, then I'd also look at the ignition coil, ICM and dizzy cap.