RSKtakR

This car has 238k miles, and has always seemed to have a slightly rough idle or sputtering I guess since we bought it last year.. its ONLY at idle though. Car has dyed while driving it 2 or 3 times over the past year. I have replaced the spark plugs but the rough idle is still there. The CE light has always been on but never been checked out. I will go have it read this evening and get the codes. I was going to just replace all four coil packs but since its just a rough idle I would think its something else? Car had the timing belt, water pump and all gaskets from the head up changed at 201k miles, has never over heated. Ideas on possible causes of the rough idle before getting the codes I think...
-O2 sensor
-IAC valve
-Fuel pump/regulator
-Something that might control spark to the coil packs (but its still just at idle so I wouldn't think it would be this).


I will post up the codes I get this evening.


Any other ideas?

GolNat

iTrader: (7)

Get the codes, it's a good starting point.

What plugs did you put in it/take out?

ezone

Read the fault codes, then make decisions.

Do a compression test.

RSKtakR

I wasn't able to pull the codes the other day, but I am doing it today after I get off work. I don't remember what plugs I put in, Ill have to look and compression is 160-185psi across all four cylinders.

RSKtakR

Ok there were two codes stored:

P1259 showed up twice
P0420 four times.

ezone

VTEC malfunction
CHECK THE OIL LEVEL NOW!!!!

#1 cause of this code is low oil level.
This code will put the computer in limp mode.
Also note how old the oil is, and condition.

Low oil level can and will destroy the engine.

Catalytic converter code.

RSKtakR

Lol ya I know what the codes are for and allllll about re oil level all to well. This motor DRINKS oil like crazy because it's just getting by the rings and burning it (I started a thread on this topic last year after getting the car).. I cleaned the vtec solenoid and screen back then and it wasn't really dirty at all, think I will check it again tho. I have been reading and read there is a way to check it to make sure it's working right so I will find some directions to do that. I read that the oil pressure sensor could be causing the 1259 code possibly to? Any truth to that?

The 0420 code... I can only assume that it's just needing the $356774567888 cat replaced because it's just a matter of time before all that burning oil trashes the cat so I wonder if that time has come now. Has anyone ever just knocked all that **** out and then put the pipe back on? I know the code will still show up but I don't care at this point I would just want the car to run better.


After getting these codes, honestly I was hoping that there would be a code that tells me wtf the misfire at ONLY the idle and the couple times it has stalled for no reason is like the ELD or whatever it is. So neither of these codes will help me with that I don't think.

ezone

Sure, just find a service manual.

HINT: If you clear the codes and drive it, and it runs great, and you can accelerate easily above 4000 RPM......the VTEC is working right now and you would not find a problem.

If it only sets the code after the oil level goes 3 quarts low, that's why the code set. Low oil level = loss of necessary oil pressure.
No need to test anything else.


That price might be kinda conservative.
Maybe you should get a calculator and recheck your estimate?
Yes oil burning can ruin the cat.

If your engine only runs poorly at idle, knocking the guts out of the cat won't help anything. Gutting a cat would only help if it were causing an exhaust restriction, limiting maximum flow.

A cat code does not indicate restriction, but a restriction might cause a cat code..

A cat code only indicates the computer decided it's ability to store and release Oxygen has deteriorated.

RSKtakR

Sounds like to me that neither of these codes will have anything to do with or fix my rough/sputtering idle. I guess I will just try to clean out ICAV and see if that's what's causing it? I was thinking the ELD and a bad upstream O2 sensor would be causing it and shooting codes but neither showed up. I noticed that the P0420 also says "ignition system concern" as a possibility. Any likelihood (and if so what part of the ignition system) would cause that code? I still just think its the cat that is causing that code though but this rough/sputtering idle drive me batshit crazy lol

ezone

P0420 is defined 'catalyst efficiency failure'. Period.

There can be many possible causes of a cat failure, ignition (misfire) is but one of many.

You always need to figure out the root cause of any cat failure, to avoid repeat failures.

That means fixing all running problems before replacing a cat, because even a brand new cat can be ruined in a matter of just minutes if the engine runs badly enough.

RSKtakR

Right and I agree. SO I know the oil level fluctuates so I will change the oil this weekend and get it full, clean the IACV, clean the throttle body, check the vtec solenoid screen, and search around online today to see if I can find the correct way to test it to make sure its working. Is there anyway to reset the ECM other than going to a dealer or seeing if Autozone or some other parts store will reset it?


EDIT, found out how to reset/clear the codes out without taking the car anywhere.

ezone

Stupid simple, no work involved: The code will not reset as long as the system works while driving.
Because the VTEC system is doing exactly what it is supposed to be doing.

That means
As long as code does not reset, the system is working correctly and you will not be able to discern any problem.
Because the VTEC system is doing exactly what it is supposed to be doing.

That means
I would not touch anything unless or until the P1259 code resets, and even then if refilling the oil makes the code stay away there is no reason to do any other work.
Because the VTEC system is doing exactly what it is supposed to be doing.

Unless you decide to fix the oil consumption problem.


And if you do decide to take the valve off to look in the screen--- if you find metal--- it's gonna be from bearings --and that would mean you have far bigger problems to think about.
Trashed bearing(s) from running out of oil?
Reset = erase codes = disconnect battery

RSKtakR

I know that but I thought I had read somewhere on this forum that there is a way to test the solenoid when it is off the car with 12v to make sure its working correctly? The car is never taken above 4k rpms for the most part and just sees hwy miles but I'm tired of the rough/sputtering idle.


The motor is never out of oil, its jut not kept 100% full I'm sure (my wife drives the car daily) which would throw the vtec solenoid code often.


If I do ALL of this at the same time, including disconnecting the battery to reset the ECM and starting from "scratch" I was hoping to see if the codes/rough idle are gone and come back... well the converter code will return I expect.

ezone

VTEC can actually activate as low as 3200 RPM, so it's used regularly during most peoples
normal driving.


VTEC is not activated at idle, so VTEC should have nothing to do with idle conditions.

Look elsewhere for the problem?

RSKtakR

Any suggestions/ideas/opinions on where to start? What else controls/affects idle quality other then the ICAV, TB and ECM? I know plugs, air filter, fuel pump, fuel filter and regulator of course. I'm not opposed to cleaning the ICAV and TB, changing plugs again, and I think I already priced out the pump assembly at one point to. The ELD doesn't affect idle quality does it?

ezone

Not unless I can see/feel/hear/touch/smell/experience the problems myself.

Unequal compression, timing, valve adjustment, valve leakage, unequal fuel delivery, rich, lean, poor fuel quality, intake charge dilution (EGR bleed), vacuum leaks, loads, and more.


Exhaust leaks and noise, collapsed or broken mounts, vibrations and noises, etc. may be misinterpreted as running problems too.



What do the plugs look like?
Got video of the bad running?
How does it run above idle speed?
What were the results of your compression test again?
Why the wide spread? Why so low? How did you do the test?

No. The PCM uses info from that item to turn the charging voltage up or down as desired.

Wankenstein

Why Sir that would be illegal in all 50 states!...Lol.

Let's just say "a friend of mine" (wink wink, nudge, nudge) did that to his '98 Civic EX which, he no longer owns.
Removed cat, knocked out screens, replaced, installed double spark plug de-fouler on secondary cat sensor ...worked great.. no CEL's . But, please Sir.. I am not encouraging you to do that .. I'm just saying it worked for my "friend".

emich

Even slightly Bend valve/s will cause 1259 . If you are burning oil you'll screw up the new cat too. Just modify the secondary O2 sensor to fix 0420

ezone

Wait, what?
Please explain how this could happen.

emich

delete

emich

I wish I could. This happen 4 years ago with my Civic 2001 EX. I was getting 1259 regardless of the oil level.
The VTECH solenoid and the screen ware replaced with new . I was driving with Obd scan plugged in ready to erase the annoying
CEL. I drove the car like that for over a year and almost forgot that compression on one cylinder was 130 vs.150 on the other 3. took of the head and exhaust valve on the 130 psi cyl. was bend. Replace the valve and everything including compression went to normal. I didn't have 1259 since.
Can you explain that? I can't.

bsmiley

Confused that am because but we you drove Arizona seem annoying CEL to me those use ware screen random filterz faintly words cleaned OBD so scrapple LED I wavelength short will knuckles tiger do duration CAM the shaft valve same adjusted buffalo thanks.

emich

I am sorry for your confusion. I was typing on my phone. look up buffalo

ezone

The original machine had a base plate of pre-famulated amulite surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the panametric fam. The latter consisted simply of six hydrocoptic marzlevanes, so fitted to the ambifacient lunar waneshaft that side fumbling was effectively prevented.

bsmiley

Just. the point read. that I every. was trying third. to make word.

Wankenstein