1zz running rough Options

[kurt95gt]

Ok tryin to help my buddy with his 00 celi gt
The codes read random missfire the the rest read missfire cyl 1,3,4

Tryed swapping coil an it doesn't change from 1,3,4
It seems to idle ok (little rough but hold an same rpm)
Bogs down really bad then trys to pick itself up but never feels like it has any power

Any ideas guys?

[Box]

At first my thought was, what the Hell is Kurt doing now?

If coils are ok, that leaves spark plugs, plug boots/wires, and fuel injectors. Off the top of my head anyway. Eh, could try doing a compression check just to rule out rings and valves.

[kurt95gt]

Not gonna lie I've been trying to buy it all day lol

We changed the plugs an it ran alittle better
We cleaned the ocv filter an maf sensor an runs alittle better
Still throwing codes on cyl 1,4 are misfiring an doesn't matter what coil is on those cyls
So I'm lost at this point

[richee3]

I'd try taking all four plugs and coils out, then try turning the car over. Make sure you get fuel spray out of all four cylinders and make sure it's consistent. Then I wouldn't try smoking, lighting any candles, or generally starting any other fires for a short bit.

How many miles are on the car? It could be that the injectors are clogged and need to be removed and cleaned.

It could be that the primary O2 sensor has gone bad, but not so bad that it is throwing a code. I'm thinking not likely since the problem was originally just related to three cylinders, now only two. That rules out any timing issues as well.

It's either a spark related issue or a fuel related issue.

Time for a 1MZ.

[kurt95gt]

The car has 203000
I'll tell him to try checking for fuel
An I think he said his dad has a comp checker might do that too

Wish he'd just sell it to me
2zz swapped dd lol

[Box]

With 200k+ miles definitely look into the injectors then. My brother's Maxima had another injector go out with no warning Saturday. Had one go out in the same fashion last February. Wouldn't hurt to change out the fuel filter while you were at it. Since plugs are new and coils checked out, definitely leaning towards injectors.

[kurt95gt]

Ok
Any easy way to clean injectors

[Box]

Aside from taking them out and having them cleaned by a shop no idea. Could try using injector cleaner, but it may or may not work. What you can do though to see if the injectors are the problem is while it's running unplug the injector and see how it effects the engine. For instance when my brother's went out we unplugged them one by one until we unplugged one and it made no difference to how the engine was running.

This post has been edited by Box: Jul 23, 2012 - 3:07 PM

[kurt95gt]

Ok that makes sense
Might run alittle seafoam through it an see if that cleans them out any
Any other little things he could check
Were trying to fix it on the cheap lol
He goes to school an has 3 kids with an ex that does nothing to help
So his limited funds are kinda tight

[Box]

If it does end up being injectors RockAuto has some re-manufactured ones for $27.79 plus a $10 core charge. Could try pulling them out and flushing them out with Seafoam or other cleaner. Definitely better chance of getting them clean that way, versus running cleaner in the fuel. Since spark is good definitely would be fuel or compression. Seeing it's only on two cylinders that'd rule out fuel pump, fuel pressure regulator, or fuel filters. Not sure how hard it is on the new Celica, but could move the injectors around and see if the misfire moves with it for a definite confirmation on it being the injectors.

[kurt95gt]

Ok just talk to my buddy again
The o ring on cyl 4 was bad
So he replaced it an noticed if he left the background line off the valve cover it runs 10 better
So could it be a bad Pcv valve?

[Box]

What it sounds like then, at least it's not helping matters. Should be able to get a new PCV valve for $5 or less.

[kurt95gt]

Yea if I don't have a spare one that fits
He says take off is still rough but the way its running right now could still be due to the bad Pcv so well have to wait an see
He's gonna get a new one tomorrow an run some seafoam through her an see where we stand from there

Thanks for the advise so far guys

[Box]

Alright, hope it works for him.

[Smaay]

have you done a compression check? 1ZZ valves are notoriously known to "dish" meaning that the valve clearance is near 0 therefore the valve is floating open. first check the compression, if its low thats a starter. its also a 2000 GT which is know to burn oil like crazy. so that could also be an issue.

here is a 1ZZ valve, you can see how its dished and not flat

[kurt95gt]

Ok thanks smaay
Well try an do that this weekend

An I assume the only fix for that is to rebuild the head right?

[Neon90424]

my 03 1zz burned oil like a sunovabish

[kurt95gt]

Well we think we figured it out
She's only running on 2 cyls
The compression was good an close on each other psi wise
But if you unplug the injectors on cyl 1or4 no change
Swapped the injectors on 1 an 2 an it moved to missfire to cyl 2,4
So guess it just bad injectors


Thanks for the help guys

[Box]

Glad you were able to find the source of the problem.