Misfire Codes

[Bipod]

Well I've been to the dealer twice :(... My S is showing misfire codes for all 4 cylinders. The tech said it happens randomly... first all 4 then only 1-3 then 1,2,4 then 1... they're a little confused. I had taken out the plugs and regapped to .034 four weeks ago along with some injector cleaner since it seemed rough at idle. It ran fine for a couple weeks, but then last week it started running rougher and the CEL came on. I took it in and they said I hadn't torqued the plugs enough, they fixed it and it was okay til today...CEL again. This time the confusion... the tech regapped again to .040 and the CEL came back on immediately. So I have them ordering OEM plugs to put in Wednesday. If that doesn't work they want to do a leak down test...they think it might be the o-rings on the injectors??? Any thoughts here? I have the car, but the CEL is on and I'm trying not to drive it much. Maybe I should just not work on my car... :D and leave it to the pros?

[Jays2k]

sounds like they are gonna go through the right steps. Spark plugs, they should check the MAP sensor too, and injectors....

[VinhPham]

A leak down test certainly wouldn't hurt. Your problem does sound suprisingly similar to mine when my car throw the random misfire code. You might want to have the dealers check out your coil packs. Although coil packs don't tend to die that often and don't seems to be intermitenly work and not work...things do happen sometimes. I've gone through the whole troubleshooting mess with everybody including Repiv and tried everything from injectors to compression test but it was the coil indeed. I first though it was the plugs too. Did you pump gas anywehre foreign lately? Could it be a case of bad gas. Just something to consider. I hope this helps. Good luck

[Bipod]

Did all the coil packs die for you? Or just one?

[My_yella_s2k]

when a car misfires, esp with all 4 misfires, it will throw a random misfire code p300...

leakdown test wont provide toooo to much info, but it can provide ring leakage from blowby, a bad or sticking valve, hg gone bad.. etc.... mostly gonna be a failled injector.... or something towards that effect... keep us posted.
and if u need any help, i work for Honda, in NJ.....

[s2k 4 me]

I hope ya get it all worked out Kerry :thumbsup:


And I wont comment about you working on your car :poke: :D


It must be the yellow, seems like they have the most problems :rofl:

[Bipod]

It must be the yellow, seems like they have the most problems :rofl:

:rofl:!!! Funny you should say that... I was thinking that when I get the Yaris next year, I was gonna get RED!!! :D

[joe_s2k]

:rofl:!!! Funny you should say that... I was thinking that when I get the Yaris next year, I was gonna get RED!!! :D :yep: Red :yep:

[repiv]

I had taken out the plugs and regapped to .034 four weeks ago along with some injector cleaner since it seemed rough at idle. It ran fine for a couple weeks, but then last week it started running rougher and the CEL came on. I took it in and they said I hadn't torqued the plugs enough, they fixed it and it was okay til today...CEL again. This time the confusion... the tech regapped again to .040 and the CEL came back on immediately. So I have them ordering OEM plugs to put in Wednesday. If that doesn't work they want to do a leak down test...they think it might be the o-rings on the injectors??? Any thoughts here? I have the car, but the CEL is on and I'm trying not to drive it much. Maybe I should just not work on my car... :D and leave it to the pros?

First of all, you need to provide more details than what's here.
Why did you re-gap the plugs to 0.034"? Are you FI? If not, then why did you narrow the gap? Just re-gapping an old plug (without checking their condition and cleaning them) is pointless.
Mild injector cleaner like the kind you dump into the gas tank may be too late for your car. Your injectors may be far beyond anything this sort of injector cleaner can do. You may need a concentrated injector flush that's hooked up to the fuel rail.
They said they weren't torque enough. What torque did you use? Did you use anti-seize when you put them in?
A bad plug that's gapped more narrow, then opened up again (without checking condition and cleaning) is also pointless.
Get the new plugs, check them for the proper gap BEFORE putting them in. Use anti-seize and torque them in using 18 to 20 lb/ft. Randomly mixed up all the coil packs (you may have one or more bad ones). Check the MAP sensor connection. Failing this, check fuel pressure, check injectors, check valve adjustment. Failing all these, you may be looking at a new ECU. I'm assuming that all your other maintenance is up to date.

[s2k 4 me]

:rofl:!!! Funny you should say that... I was thinking that when I get the Yaris next year, I was gonna get RED!!! :D

Sweet!!!!!!!!!!! That Yaris might just turn out to be faster than your S :thumbsup: :rofl:

[Bipod]

First of all, you need to provide more details than what's here.
Why did you re-gap the plugs to 0.034"? Are you FI? If not, then why did you narrow the gap? Just re-gapping an old plug (without checking their condition and cleaning them) is pointless.
Mild injector cleaner like the kind you dump into the gas tank may be too late for your car. Your injectors may be far beyond anything this sort of injector cleaner can do. You may need a concentrated injector flush that's hooked up to the fuel rail.
They said they weren't torque enough. What torque did you use? Did you use anti-seize when you put them in?
A bad plug that's gapped more narrow, then opened up again (without checking condition and cleaning) is also pointless.
Get the new plugs, check them for the proper gap BEFORE putting them in. Use anti-seize and torque them in using 18 to 20 lb/ft. Randomly mixed up all the coil packs (you may have one or more bad ones). Check the MAP sensor connection. Failing this, check fuel pressure, check injectors, check valve adjustment. Failing all these, you may be looking at a new ECU. I'm assuming that all your other maintenance is up to date.

Yup I'm FI! Have a Comptech s/c and followed your plug FYI (great FYI by the way :)) Looked at the plugs they looked clean, have 20k miles on them. Should I have the dealer narrow the stock gap to .034 or just run stock gap when they are replaced tomorrow? Apparently I used a torque wrench that wasn't giving me true torques... bad me :nono:! I always use Chevron gas and I never needed injector cleaner in my MY01 when I had it... I know, different engine, different car... so I would be surprised if my injectors were dirty... but I figured I'd give it a try. Anyhoo, I'll keep y'all informed of what they find. Luckily they haven't charged me any $$ yet... :nervous:

[Geo02s2k]

Hate to say it, but it sounds a lot like the problem I had 1.5 years ago. I started throwing misfire codes and the car would puff a bit at idle. They tried most of the things you've already done before finally replacing the fuel injectors. I might have gotten some bad gas after hurricane Rita. It's run flawlessly since (knock on wood). Sounds like they are following all of the correct steps, though. Good luck and let us know what happens.

[Jerome]

Bipod, You did not say what Brand and ID number of the spark plugs you were using. If you gap the new OEM plugs at .032" and you still have misfire codes, please let us know what you find as the problem source.

Jerome
NW Arkansas

[VinhPham]

Did all the coil packs die for you? Or just one?

It was just one but Honda dealer think I should change all 4.

[Bipod]

and the car would puff a bit at idle.

What do you mean puff at idle? :nervous:

[Bipod]

Bipod, You did not say what Brand and ID number of the spark plugs you were using. If you gap the new OEM plugs at .032" and you still have misfire codes, please let us know what you find as the problem source.

Jerome
NW Arkansas

Jerome, there are two valid sprk plugs listed for use in my 05 S... the NGK:PFR7G-11S or the DENSO: PK22PR-L11S... I'm currently running the DENSO plugs, and they gapped them to 1mm (.039") at the dealer yesterday, but that didn't work. I'll let you know what the new plugs are and how they turn out...

[repiv]

OK, with FI, go with 0.034" for the new plugs, but swap all the coilpacks around, "freshen up" the MAP connection, reset the ECU and see what happens.
If this was a sudden thing, then I doubt it's the injectors being clogged. You should also double check all the Comptech ESM connections. Those have been known to degrade and give symptoms like you've seen.

[Geo02s2k]

What do you mean puff at idle? :nervous:

When the car was idling, you could hear the puffs coming from the exhaust when there was a misfire. Kind of a "puh" sound that interrupts the normal exhaust sound and you'll feel the engine shudder ever so slightly. The exhaust sounded like "mmmmmpuhmmmmmmmmmpuhmmmmmmmm".

[Bipod]

Okay here's an update before I go to the dealer again today... I got in may car after work yesterday and the CEL was off!! I couldn't believe it... no shake in the engine, no puffs in exhaust sound (Thanks Geo, that's the perfect description)... everything seems to be running fine again. So here's a question... Could it be that I have a bad wire somewhere in the harness that supplies the spark plugs? It has been insanely humid here (since it's Tucson and we never have wet) in the 80% and above range and we've had the most rain I've seen in this monsoon since the 1983 floods!!! :eek: I'm wondering if I got some moisture in the wires somewhere, and if there's an easy way to check for problems in the harness? I'll let you all know what happens with the dealer check up.

edit: yesterday was the first fully sunny day we've had in weeks. So the car actually dried out completely...

[repiv]

The stock wiring and electronics on this car is not known to be affected by environmental conditions. However, the Comptech ESM wiring is. Many have reported odd running conditions off and on. Double checking and soldering or re-soldering those connections have resolved the situation. The CT ESM infiltrates the MAP signal. A MAP signal that comes and goes can sometimes give a CEL and sometimes not. It can also create odd engine running symptoms.

[foolio]

I've been having the CEL and misfire problems for a while now, and I finally took it into the dealer. They diagnosed the problem as a faulty injector, so now I will wait to see if HondaCare extended warranty will cover it.

[repiv]

I want to bring something up at this point so that we can discriminate the different between some of the reported symptoms we've been seeing here.
1. Bipod's car is Comptech supercharged. He has added wiring that IS affected by humidity, air pressure, temperature, etc.
2. His symptoms comes and goes. When it's bad, the car doesn't run right. And for no "apparent" reason, the next time he gets in his car, it runs like nothing is wrong. A faulty or bad injector stays faulty or bad. It doesn't just come and go. Same goes for a bad sprak plug or a bad coilpack. Once they go bad, they don't miraculousy heal themselves with no intervention.
I have seen CT cars that have run perfectly for months and years and then suddenly these "on again, off again" symptoms crop up. Dealers have changed MAP sensors, injectors, spark plugs, coilpacks and the problem was fixed, BUT they CAME BACK in the same "on again, off again" scenario.
Bipod's case is unique simply due to the fact that ECU wiring has been tapped into. If it was a well define issue that came and remained and never changed, then sure, something else needs to be targetted. But since it suddenly runs fine on a later occasion, we must refer ourselves back to circumstances that are different before we start to change things like injectors, plugs, coilpacks, etc. It may well be one of those things still, but for now, it might be more useful to draw upon past experience and eliminate those things that were added. Resolving wiring issues from things added on may be tedious and frustrating, but in the long run, it may be cheaper than replacing parts that may not be broken. The problem being that if you replace something and the problem goes away, you then have to wait and see if the problem comes back later when similar conditions can be duplicated. If that happens, what will you replace next? Of course, the choice is yours.

[centralcoastbuc]

Just a small correction. "She" rather than "He". (Bipod is a women and also the Southwest Regional Director).

[repiv]

Just a small correction. "She" rather than "He". (Bipod is a women and also the Southwest Regional Director).

Didn't know that. Thanks for the correction and sorry for my ignorant assumption. :o

[Bipod]

Didn't know that. Thanks for the correction and sorry for my ignorant assumption. :o


Ahhh, not to worry... I've been one of the guys my whole life :D :thumbsup: Thanks for all your help!

So are there any wires I should check to look for wear/bare spots/etc...? BTW I just drove ~50 miles for lunch (work trip) and it runs well at idle except when the a/c compressor comes on, then it runs rough, but I think it's always done that to some extent. Still no CEL, but I may replace the spark plugs anyway when I get some new tires mounted next week...

[Bipod]

Welp... here's the long story update on my misfire problem...

A couple months ago, I finally had it! I took her back to the dealer and they took out the injectors and said I need four new ones!!! :yikes: I went in to have a look and they're covered in some nasty sticky goo... the dealer didn't think they'd come clean with any cleaner. SO $800 later I have four new injectors! Then just after that (engine running fine again) I noticed my mileage dropeed a couple MPG... oh no... So, about 2 weeks ago, I finally got in to Science of Speed and had the guys do a check of the system and S/C to see what's the deal?! After a dyno and tune on the new injectors... and putting 293 HP to the pavement with no A/C on the S/C... they turned the fuel pressure all the way up and found that my fuel pump just isn't doing the job!!! Well, now I'm headed to SoS again on the 17th to get a new pump... Hopefully this will be the last of these issues... They will do a dyno with the new pump for tuning, so I will post up the final results when I have them. This car is so much fun to drive, but I have no $$$$ left to do anything fun :( Oh well...

[centralcoastbuc]

Thanks for the update. I hope you get it fully resolved soon!

[Bipod]

thanks for the thoughts... :thumbsup: i hope this is it for a while :)

[stantaur]

Had a similar symptoms - occasional misses at idle or cruise, CEL, marginal dyno (193 at the wheels stock). I pulled my injectors (30 minute job) and sent to RC Engineering for their blueprinting ($99 for all 4 at the time). One injector showed up as 300 cc/min while the others were at 358 cc/min. They cleaned & re-tested all at 360 and sent 'em back 2-day air. Pretty nice customer experience. Cured the issue and the car ran sooooo much more smoothly.

Best of luck with the fixes.

Stanford

[Bipod]

I've never tried to do important engine work like injector removal/replacement... Is this something I could've done myself (in hindsight)?

[repiv]

I've never tried to do important engine work like injector removal/replacement... Is this something I could've done myself (in hindsight)?

I think if you can change spark plugs, you can change injectors.

[alvanderp]

I think if you can change spark plugs, you can change injectors.

Agreed - just make sure you use new O-rings if you decide to get the current ones cleaned and bluprinted like Stanford mentions.

[stantaur]

Yipper. Good analogy with the plugs. Probably a step-by-step guide with photos somewhere on this site or the other S site.

Adding to Alvenderp's good idea for new injector o-rings is to get new washer/seal that goes under the little white knob/connector (Honda part guide calls it a muffler seal IIRC) that attaches to the fuel rail.

Enjoy,
Stanford

[Bipod]

Thanks guys!! I'll probably just keep the new one's the dealer put in....for now. But I do have this set of "gooey" ones. How do I go about cleaning them up and checking to see if they're still good? If I ever need new injectors again, I'll probably do the job myself, with all of your help of course ;)