DannyK35

Well, here goes nothing:

I have an old thread https://www.civicforums.com/forums/3...lp-please.html here, describing this bullshit issue I've had to deal with for a while and it has never been fixed. All I can guess, thanks to several 7th Gen members, is that it is an ECU issue.

I've been driving it regularly lately, haven't been beating on it and I'm still getting like 25-29mpg which is just awful.

CEL is always on, got it checked last weekend and there were TEN codes, all were misfires from all cylinders, random misfires, and CAT below threshold.

I could really care less about the CAT issue. It's these misfires that stump me. Replaced injectors, coil packs, plugs are gapped right, valves adjusted, crank angle sensor is fine, compression test was fine, all that good stuff. So basically, I don't know what else it could be.

I'm driving from Chicago to Seattle on Sunday and just b/c I'm a paranoid person, I would like to try and fix this one last time before I hit the road.

The car has 149k right now and I'm going to get the timing belt and water pump replaced before I leave.....turns out that this car has never had that service done to it......ever.

So, if anyone still kicks it on 7thgen.com (aka civicforums.com nowadays) and has any input, help out a longtime member with your suggestions and input.


Thanks guys!

gearbox

iTrader: (95)

ahem, well the cat could very well be the issue. if its clogged it can cause major problems in the way the car runs. i think that should be the FIRST priority even if you just get a universal cat welded in to fix the problem. have you examined the plugs after changing them? do they look normal tan color with no weird stuff? there are not alot of things that cause a misfire. basically if the actual plugs are performing well and there is nothing funny going on like oil leaking on them, coolant on them, etc then the only other possibilities are fuel delivery problems (have you checked the fuel pressure lately?) or air delivery, or a problem with the sensors (unlikely if the cel doesnt say anything). other than that, maybe your ecu is messed up and unable to adjust the ignition timing. does the car actually feel like its misfiring? even single cylinder misfire will make the car shake like a ****.

DannyK35

Misfires only occur on the highway, and I don't even feel them. Thanks for responding Gearbox, you are always on point with this stuff.

edit: also, there was nothing bad on the plugs. Also, before all this happened I know that a code was thrown in regards to the CAT. This was a very long time ago, and there was no difference in MPG when that happened until the misfire codes started showing up.

Also, with those most recent (ten) CEL codes that came up, there was only one CAT below threshold that showed up. Not sure if that helps.

greeen01civic4d

iTrader: (7)

u will only get one code for cat efficiency below threshold, id bet on the cat being part of hte problem, try the defouler first, see if it helps, if it does, replace the cat, or run the defouler

DannyK35

Thank you green01civic4d.

As soon as I research wtf a defouler is on this stock 7th gen, it will help. having the timing belt/water pump done by a honda tech soon so that will be helpful.

gearbox

iTrader: (95)

also, what are the ten codes? all misfire related like one per cylinder, multiple, and random?

DannyK35

each cylinder (1,2,3,4), multiple, and random. I think they are what, 301/302/303/304/305? That , and the cat below threshold (I think that is 420 or 402? Don't have my notes by me right now).

greeen01civic4d

iTrader: (7)

a defouler, or non-fouler, is something used on spark plugs to keep them from fouling as quickly, all u need is 2 18mm nonfoulers from a parts store, drill one out with a 1/2" drill bit, screw together, screw the secondary o2 sensor into the assembly u made and bolt back into the pipe, it blocks flow from the o2 sensor, keeping it from getting as many emissions, leveling oiut the fuel mixture, if it fixes the problem, replace the cat, if not, it may be a vacuum leak problem

DannyK35

here are the codes:

P0420 Catalyst System Efficiency Below Threshold
P0300 Random/Multiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected

-------------------------------------------------------------------

As for the defouler, I will look into that as soon as possible. Thanks guys so far for all of your help.

gearbox

iTrader: (95)

fix the cat, check fuel pressure, run some cleaner (valvoline is good if you cant afford FP60) thru the gas, make sure your grounds are good and coils are getting enough volts. you can put a multimeter on one of the coil plug wires and it should be 13.9v with car running.

DannyK35

FP60 was ordered last weekend, waiting for it to arrive at my doorstep.

Multimeter tested out fine at 13.9v last time it was tested, running 4 new (well, slightly used but newer than my originals) coil packs from a fellow 7thgen member.

As for the cat, you said universal cat welded? Are those okay for our cars? (n00b question, I know. I'm assuming a universal cat is cheaper right?)

gearbox

iTrader: (95)

the only problem is in cali, you need a special one for their low emissions. otherwise a universal would be fine. ask an auto store if they have one for the car. its tons cheaper than oem one and should work the same. restricted exhaust is a big problem. im assuming your 8 yr emissions warranty is over by now if you have 01.

speedfoos

iTrader: (17)

Yes a universal cat is much cheaper, you can get a 50-state emissions compliant Magnaflow one from Summit Racing for like $65. get a 2.25" inlet/outlet one it should weld right up.

Here's the part number: MPE-53005CA

Here's the defouler, but you shouldn't need one once you get the cat replaced.


This will back the O2 sensor out just enough to fool the ECU into not throwing a code. You don't have to order them from Amazon, your local Vatozone should have them on the shelf. Just look for the "Help!" brand of parts in the red packages.

DannyK35

Right on guys, if a universal cat is that cheap I'm just going to scrap the defouler and go right for the new cat.

Getting a new timing belt and water pump put in tomorrow at a shop that does good work (cheap) so I'll see what they'll do for me on the new cat.

Thanks again, I'll keep this thread updated.

speedfoos

iTrader: (17)

And that cat is legal in California, hence the "CA" at the end of the part number.

DannyK35

Alright, got a shop here in Chicago to do the magnaflow cat for $210 out the door on Friday. One less variable to deal with. Thanks again guys.

2002civicLX2002

a plugged cat WILL cause the engine to miss. im betting thats your only problem, even though there is only one code for it.

greeen01civic4d

iTrader: (7)

keep us updated man

DannyK35

VICTORY.

(well, at least for now)

Just got the car back from the shop. Turns out that I also needed to get a new valve cover gasket to replace the old one, it was slowly leaking oil.

I got it back about 1.5 hours ago and god damn the difference was noticeable immediately! Not that these cars are fast/quick but holy **** it was like I was driving a completely different car than I have been for the past few months!

Here is what I had replaced today:

- timing belt/tensioner (OEM)
- water pump (OEM)
- magnaflow catalytic converter
- valve cover gasket

Total cost w/labor and tax: $630. Found a Honda tech online that does side work on his days off, that's a pretty solid deal.

So I'm pretty stoked and not freaking the **** out about this 2000 mile trip I am taking on Sunday, I just wish I figured that out earlier. And I'll throw the FP60 from lubecontrol.com when it comes tomorrow just for the hell of it.


I want to thank everyone here on 7thGen (I mean civicforums.com) for their input and suggestions, you have no idea how appreciative I am.


Thanks Everyone, and I will update this thread if anything pops up (hopefully it won't).

2002civicLX2002

I had a suspicion is was a plugged cat since it was missing on all 4 cylinders. thanks for the update and good luck and safe trip.

greeen01civic4d

iTrader: (7)

congrats man

DannyK35

Well, I spoke too soon.

I have been driving it on the highway to test everything out and low and behold, CEL comes on while I'm doing 40 down the street. Ran it over to autozone, only code that popped up (2 times, mind you):

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

So, I'm going to have to guess that it's a faulty oxygen sensor for now. All of the other variables that could cause this are not there (no vacuum leaks, brand new cat, etc).

However, I can tell that my mpg is back up to normal b/c I've got a little over a half tank left and I've put on 180mi from a full tank.

Any suggestions or is it even worth bothering to replace it right now? Leaving tomorrow for Seattle.

gearbox

iTrader: (95)

prolly replace secondary o2 sensor. it wont affect how the car dirves tho. just do it to turn the engine light off.

DannyK35

well, just a post script:

Made it to Seattle in less than 2 days, never got the o2 sensor fixed.

However, damn what a difference after the repairs. I averaged 35-38mpg the entire way (best tank was actually 42mpg), doing 85mph and driving through the mountains. Pretty damn good.

gearbox

iTrader: (95)

nice glad you made it okay

greeen01civic4d

iTrader: (7)

u comin back to chicago?? i was in linkoln park the past weekend..

utahbmxer

Not to Jack a thread. I've been having the same P0300 (random), P0301, P0302, P0303, P0304 misfires as well for the past few weeks. I also had the P1298 (High Voltage in ELD) but I fixed that by replacing the ELD. I can't seem to figure out why I am having all these random misfires. I replaced my plugs, did a fuel pressure test (came out @45psi). I ran Seafoam through tank and throttle body, tried Premium gas this tank. I did pop one P0420 (CAT below thresh) code a few days ago, but it hasn't returned. I am thinking there is some electrical issue, possibly bad ECM. Anyone have any thoughts? I don't want to drop money on a new ECM and have that not be the problem, and I can't find any at the wrecking yards.

-The car shakes bad under say 1,300 RPMs, especially when cold. I can feel and hear it misfire. CEL flashes at this time.
-Doesn't seem to misfire over 1500RPM
-When I drive on the freeway and come to a stop the engine almost dies at like 400 RPMs or below, then slowly creeps back to ~700
-On another note, Car has done a weird idle down when I let off the gas, since I got the car with 62k mi. See video: [YOUTUBE]http://www.youtube.com/watch?v=InNzjZkAirg[/YOUTUBE]

2001 LX Sedan
5spd
AEM Short CAI
DCSports TCS Exhaust
149,000mi

Thanks,
utahbmxer

gearbox

iTrader: (95)

whoa the idle is screwed up bad. try cleaning the whole intake system, throttle body, iac valve, everything. put it all back and relearn the idle. i also think the cat might be going bad (clogged) or maybe the 02 sensor for it also.

WannaBFast

iTrader: (16)

the flashing CEL is VERY bad, it basically means you got a misfire that is probablly damaging your cat.. if it already isnt already

might have a clogged cat, or a sensor that is broken

Krieger

x2.

thats crazy.