Cobalt_noob

Whats up everybody?

So i got my cobalt back together after a long hiatus from bent valves and etc etc.

I got the head rebuilt and its practically brand new. I got it installed over the long weekend and assembled everything else until it was up and running.

Now, im having the same issue as before when my valves bent. On top of having misfires (the misfires are happening at idle and when im coasting down mostly)!!!! But when i start to lean in to the pedal and give it some gas, it starts to "buck" or cut out briefly or something of the sort.. its kinda hard to explain...... basically, i can not give it full throttle or it starts actin pretty crappy.

ive got brand new plugs, coils, fuel filter, last time i checked the fuel pressure was good, ive been checking for vaccuum leaks and cant find anything............ can someone shed some light please???????

jdbaugh1

iTrader: (1)

Do you have any idea what your air to fuel ratio is while this is happening?

Cobalt_noob

Ive got my wideband, but ive yet to hook it up.... you think that might be a go to step??

its just been crazy man, between kids, a wife and life.. what you thinkin it may be?? lean possibly???

jdbaugh1

iTrader: (1)

Do you have the bung on your downpipe for the wideband? If so maybe you could do a sloppy temporary install to at least see what the fuel is doing.

From what I have seen with 2.2 SC builds (similar to 2.4 I'm assuming) with canned tunes is that the fueling is usually pretty far off. Enough to cause the symptoms you are experiencing. I have seen these issues corrected with a proper tune.

Cobalt_noob

Well i know what ill be doing when i get home then! Ill hook up the wideband and report the findings. (dont have HPTuners YET)

ECaulk

iTrader: (6)

I'd bet the tune needs some serious help. I wouldn't drive it till you have the wideband and hptuners

Cobalt_noob

well ive got to drive it home from work unfortunately... 56 miles one way and this is day 2

Cobalt_noob

Its dumping buckets outside so ill have to wait unfortunately

Cobalt_noob

Alright guys, so I got the wideband up and running. The misfires have been progressively getting worse. But the wideband has been jumping erratically between 14.1 and 14.9 (this is at idle) and then all of a sudden go SUPER rich and then back up to 14.1 and 14.9 jumping around. When I give it just a wee bit of gas, it goes way way lean.

But my buddy had his scanner over (not hp tuners, just some brand) and we were able to see STFT, LTFT what the O2 Sensors reading etc...

Well we were able to see which cylinders were showing misfires...... Cyl.1 - 4 total misfires .... Cyl.2 - 946 misfires .... Cyl. 3 - 100 misfires ..... and Cyl. 4 - 0 misfires. WTF?!

I'm thinking the worst here, but ive got to hear it from you guys... what do you think it could be. Ive checked spark, spark plugs, vacuum, etc... I'm worried its the head gasket...
please help, I'm at the end with this thing, ive gone to hell and back.

jdbaugh1

iTrader: (1)

I'd pull the plugs and compare them to the plug in Cylinder 2 and see what is different. Also compression test. Do you ever get a flashing check engine light for misfires?

I think it is part your tune but that wouldn't cause a disproportionate amount of misfires in one cylinder.

Cobalt_noob

I am going to pick up a compression tester here really soon, if not this weekend then the next.

I have gone through 4 brand new sets of spark plugs lol. But yeah, ill take a look at Cylinder 2 specifically and compare. Im worried that its the head gasket. Its brand new, but i installed the ARP head studs and im wondering if I got all the studs bottomed out before i torqued the nuts... this car has plagued me with misfires since ive owned the s.o.b.

jdbaugh1

iTrader: (1)

I'm not telling you to change the spark plugs but to take them out and compare them making sure to keep track of what cylinder they came out of. Could just be a compression leak or hg problem in that one cylinder. I don't think that one cylinder is causing all your issues either though. When my engine was running I always had more misfires in a couple cylinders than the others but they were closer than what you showed.

Cobalt_noob

I gotcha. So you think its a combination tune and possible compression leak or head gasket problem possibly??? Sorry man, noob here

jdbaugh1

iTrader: (1)

I'm a noob as well just trying to help if I can. Hard to say. All I know is that a tune won't cause 1 single cylinder to run poorly compared to the rest but it also could amplify a small variation. You need to investigate more to see what could be causing the variance in that single cylinder. You didn't answer me if you ever got a flashing CEL or actual misfire codes.

Cobalt_noob

Oh my bad, no. Thank god, no flashing CEL's! And yeah, ive been periodically getting the P0300 code, and then ill clear it with the Aeroforce gauge and then a day or two later itll come back on. The weird part about it though is that when my buddy hooked up the scanner, it was showing pending codes of P0300, which was to be expected. But after we stood around and scratched our asses on it for a while and packed up shop, this morning when i fired it up.... P0302! so it wasnt until after the fact that we were able to monitor which cylinders were having misfires did it finally make up its mind to say "Oh yeah, btw P0302.. just thought that would help you out since ive been giving you p0300 all the time" Friggin car.

jdbaugh1

iTrader: (1)

Yeah I was wondering if the computer decided cylinder 2 misfire count was far enough out of range to warrant it's own code and not just P0300 because I don't really have a good idea of whats normal, acceptable, or when you really have a problem as far as misfire count variation.

WICobaltSS

Hey Guys,
Been watching this thread with interest. Looking at the misfires in cylinders 2 and 3, wouldn't that be an indication of a possible head gasket leak? As a noob also, I've been researching for issues with poor engine performance as mine seems to act weird also.
I think a compression test will help shed light on your issues. Best of luck.

Cobalt_noob

Thanks man. And yeah, what ive read on possible head gasket leak when it occurs between cylinders is that it may not be detectable by a compression test... although, a leak down might help more than just a compression test. Its tough to say. And im putting my money on a head gasket leak myself, just because i installed the ARP head studs and am not sure if i cleaned the threads out good enough in the block, hence, they are not sitting all the way down in the holes like they should..

Im not exaggerating when i say i have been plagued with misfires in this car since the day i bought it

Cobalt_noob

Gotcha. One thing is for sure that Cyl 2 and Cyl 3 got something going on together. although 2 is seriously got the problem. ill take a look at the plugs, compare and update yall.

WICobaltSS

What did the head rebuild cost you in time and money? Debating on doing this myself.
In your case, hoping it's just a matter of thread cleaning.

Cobalt_noob

well for one thing, get yourself a good valve spring compressor, trust me (and that's if you're going to do it yourself). But, its a bit pricey man, especially if you dont got the cash just laying around. Do some research on what valves you want ( I went ahead and bought supertech valves from turbotechracing.com the guy is really cool, ask him anything and he gives a good unbiased answer) I also bought supertech valve guides. And valve springs (highly highly recommend if you don't do anything else) get ZZP's 82# springs with titanium retainers. If you would like a full breakdown on doing it yourself PM me and ill give you the whole deal. But, if you're going to have someone do it, IE a machine shop, suck it up butter cup and call around!!!! I got really lucky and found a reputable place, made the head look brand new... $300! Got lots of compliments on it, they did a phenomenal job! But yeah man and if you want to know what it costs to do it yourself, just PM me.

royce777

iTrader: (29)

Few questions.


Who tunes you?

Who does the engine work for you?

Did you try swapping coil packs to see if the misfire follows that coil pack?



I just briefly skimmed the thread. Im local to you, south of Pittsburgh. Just wondering if you got your work done locally. There are a few of us locally with HPT that hook you up with a good tuner.

Cobalt_noob

Good stuff man.

As far as all the work goes, its been me and some close friends. The head work I got done in Greensburg by P and R Engine Rebuilders.

The tune I got a canned one from ZZP. As jdbaugh stated, a tune is definitely in order. But there is for certain some underlying issue at hand and can't seem to find.
Coil packs were brand new, however, today we were going to definitely rule it out and swap them around. I did pull the connector one by one and verified that they were giving spark, which they are. How strong of a spark is the question and also ignition timing possibly.
So I'm at the crossroads with tuning. I bought the the tuning schools book on how to tune and wondering if I should purchase HPTuners and do it myself, OR take it to this place in Export PA (around the Washington area) as they are supposedly pretty good. They're called FJ Performance. So I dunno man.

royce777

iTrader: (29)

Did you ever figure out what caused you to get bent valves last time?

Cobalt_noob

Oh yeah man, i got a thread on that too lol. But in a nutshell, the stamps the GM put on the cams were exactly the same to a T. And i swapped the intake for the exhaust cam by accident ohhh boy, but before that i was having issues that i was trying to fix... come to think of it they were misfires. And i had pulled the head to re-seat the valves.... which, while the cams were swapped (intake with exhaust and vice versa) there were no misfires!!! so it was in fact a leaky valve seat.