trouble codes - NJFBOA - Home of New Jersey's Camaros and Firebirds

Brando56894 · 11-17-2005, 01:33 AM

hey im getting these codes and dont really know whats causing them or how to fix them:

p0303 cylinder 3 misfire detected
(kasey and i already changed the plugs and wires, well we changed 5 of the plugs cuz i had already replaced #3 and forgot about it and broke it trying to take it out, so theres an old one in there)

p0405 EGR position sensor circuit low voltage

no idea about this one...

Savage_Messiah · 11-17-2005, 02:07 AM

the old one i don't thinkw as cyl 3 anyway, and it was one of my old ones that were still sompletely fine, I just decided I wanted to change em all cuz of milage and desire to upgrade. I thought we said you'd pick up another NGK tho?

Since it's not the plugs or wires I am thinking it much be either injector or coil pack... since he recently seafoam'd his fuel system I don't think it's an injector tho unless it's just bad. There an easy way to test injectors? or the coils??

And I'm not too sure what his EGR problem is, car runs like CRAP though... hopefuly it's soemthing as easy as the gasket going but I have no idea really.

Brando56894 · 11-17-2005, 02:13 AM

my dad said some places around here could be able to test the coil packs.

Savage_Messiah · 11-17-2005, 02:30 AM

your car probably can't make it home right now.

Brando56894 · 11-17-2005, 03:22 AM

we have about a week to diagnose and fix it (or mostly fix it) i have the money we just gotta find out whats screwin it up

JL8Jeff · 11-17-2005, 07:27 AM

If it's running like crap, that's most likely the EGR not working properly. If you somehow cracked the porcelain on the plug or the wire was damaged or not on all the way it could cause the miss. The Seafoam may have caused some carbon to break loose and got lodged in the EGR, who knows.

foff667 · 11-17-2005, 08:15 AM

egr doesnt effect crap from what ive seen other then throwing codes...i pulled it off the camaro last night because eric plugged the hole in the intake but not to the exhaust...but he did remove the egr unit itself...starts & idles fine without all that...also keep in mind 98-00 ls1 fbodies had egr but yet 97+ vettes & 01-02 ls1 fbodies didnt...imo and from what i can gather egr isnt a very important piece...normally I would just say remove the egr and get the codes deleted for it thats all im doing with mine.

foff667 · 11-17-2005, 08:18 AM

I would definitly check that plug/wire for that cyclinder to see whats going on there though...if all signs are pointing to a misfire & its running like crap sounds like theres a connection...or lack thereof

Savage_Messiah · 11-17-2005, 12:10 PM

the misfire was going on even before the plugs and wires were changed

Injuneer · 11-17-2005, 01:57 PM

EGR won't affect the way the car runs, as long as the valve isn't leaking. Removing it isn't going to affect the way it runs either, particularly start and idle, since it isn't used at startup or idle. But if the EGR is still there, and the EGR valve is leaking, it can cause misfires. If it was causing misfires, it would more likely cause P0300 - random misfires.

P0405 is basically checking the electrical continuity of the EGR position feedback sensor. Could be a problem with the wiring to the valve or in the pintle position sensor on the valve. If you had an EGR leak, it would more likely cause other EGR codes to show up, so I don't think the P0405 and the P0303 are necessarily related.

As noted above, anything that affects Cyl #3 is suspect. If you've ruled out the plug and wire, as noted above there's still the coil and the injector. And it could also be a valve problem... e.g. lifter.

Brando56894 · 11-17-2005, 03:40 PM

ive been gettin the mifire code for about 4 weeks now (first noticed it on my way down to the trucks in late october) so i changed the plug and wire on 3 and that seemed to fix 90% of it. alot of power was restored, i could make the tires squeal real easily, etc... the only time it would screw up is when i would floor it and it would go up to about 80 then misfire/barely accelerate. so we changed the plugs and wires but as stated before my dumb ass cracked the NGK i had in #3. after this it would bog down around 40 and barely accelerate (again) around 80. sunday (?) i took kasey out to show him what it was doin and thats when i got the P0405, i would floor it and it would barely accelerate around liek 30, then we heard a clanging noise which we assumed was the cat. after i dropped him off at his car we went to the other lot and thats when i smelled the rotten eggs. so should we remove the EGR along with cat? on our way to kaseys im prolly gonna buy 2 cans of seafoam and give it a full seafoaming..... (gas and manifold)

JL8Jeff · 11-17-2005, 06:40 PM

I thought that if the EGR was leaking it would make it idle rough and barely run. I know I've read this on a lot of different car/truck boards but I've never had an EGR problem so I can't say for sure. I wonder if you could have a burned valve on that 1 cylinder and it isn't sealing as well resulting in the misfire.

foff667 · 11-17-2005, 06:59 PM

Quote:

Originally Posted by JL8Jeff

I thought that if the EGR was leaking it would make it idle rough and barely run. I know I've read this on a lot of different car/truck boards but I've never had an EGR problem so I can't say for sure. I wonder if you could have a burned valve on that 1 cylinder and it isn't sealing as well resulting in the misfire.

unless you have a vacuum leak on the intake because of the egr your car will run fine Jeff...the 98 I just got the egr valve is missing...the intake is plugged but the exhaust isnt and it runs fine...just has a slight exhaust leak. Now a vacuum leak is a whole nother story.

Savage_Messiah · 11-17-2005, 10:25 PM

brandon I told you i dont have any welding machinary and its gonna take us a bit of customization to get the bullet on there with the stock y-pipe. so if you leave my house open y-pipe dont blame me lol

as for the EGR, you will need to block off the holes on your intake and exhaust manifolds... you know THAT right?

Ian · 11-17-2005, 10:40 PM

Jeff is right, if the EGR valve is open all the time, it will idle like crap and might stall. Its unmetered fuel being pushed into the combustion chamber, it'll run rich and will idle like crap. If you didnt change the plug and wire for the cylinder thats throwing the code, thats kinda telling you something.

Ian · 11-17-2005, 10:43 PM

ha, I just re-read jeffs post. If he burned a valve on that cylinder, it would most likely be running lean. but if you think of it from PCM point of view, it might be reading the O2 sensors and leaning it out. could be a possible cause, but if the computer leaned it out too far,he would start knocking then the knock sensor would over-ride the lean request.

Savage_Messiah · 11-18-2005, 02:40 AM

Quote:

Originally Posted by Ian

If you didnt change the plug and wire for the cylinder thats throwing the code, thats kinda telling you something.

they were changed

Brando56894 · 11-18-2005, 02:58 AM

Quote:

Originally Posted by Savage_Messiah

brandon I told you i dont have any welding machinary and its gonna take us a bit of customization to get the bullet on there with the stock y-pipe. so if you leave my house open y-pipe dont blame me lol

as for the EGR, you will need to block off the holes on your intake and exhaust manifolds... you know THAT right?

yea i know you told me that, if all else fails, ill just get a flex pipe and put that in the place of the cat, i just need somethin to get me home. if we cant get it fixed, and my dad/brother cant fix it, ill just take it to my moms mechanic, i have the money. as yes i know that about the EGR...

Savage_Messiah · 11-18-2005, 04:13 AM

right but i am saying that the cat it now appears is NOT the source of your problems, in which case removing it and band-aiding it with a flex pipe won't make a difference. if you want I'll take a look at your EGR and see if anything is blatantly awry

JL8Jeff · 11-18-2005, 07:26 AM

Quote:

Originally Posted by foff667

unless you have a vacuum leak on the intake because of the egr your car will run fine Jeff...the 98 I just got the egr valve is missing...the intake is plugged but the exhaust isnt and it runs fine...just has a slight exhaust leak. Now a vacuum leak is a whole nother story.

But that's what a bad EGR would be, the same as a vacuum leak in which unmetered air would be getting into the intake and the computer isn't compensating for it other than reading the lean mixture from the O2 and then adding fuel. But like I said, I never experienced it but this is what I've read about on the EGR.

foff667 · 11-18-2005, 07:51 AM

Quote:

Originally Posted by Ian

Jeff is right, if the EGR valve is open all the time, it will idle like crap and might stall. Its unmetered fuel being pushed into the combustion chamber, it'll run rich and will idle like crap. If you didnt change the plug and wire for the cylinder thats throwing the code, thats kinda telling you something.

un metered air you mean i assume...yeah to that extent your right it would be very similar to a vacuum leak at that point.

foff667 · 11-18-2005, 07:53 AM

egr's aint cheap id say look on the camaro sites to people parting out their cars to try and get a new one on there....on cv6 i saw one for $10

foff667 · 11-18-2005, 07:54 AM

Quote:

Originally Posted by JL8Jeff

But that's what a bad EGR would be, the same as a vacuum leak in which unmetered air would be getting into the intake and the computer isn't compensating for it other than reading the lean mixture from the O2 and then adding fuel. But like I said, I never experienced it but this is what I've read about on the EGR.

yeah i guess it didnt register at first considering my egr is off the car but theres a blockoff plate on the intake meaning i dont have a vacuum leak...brain fart i guess lol

Injuneer · 11-18-2005, 09:33 AM

If the EGR valve sticks open, it dumps exhaust into the intake. The engine runs poorly, bad enough to stall. The standard test for the EGR valve is to let the engine idle, force the valve open manually, and if the engine runs rough and stalls, that shows you don't have a problem... the EGR valve is sealing properly.

The engine will run fine with deleteing the EGR. But if you have a valve that is leaking exhaust into the intake when the PCM isn't expecting the exhaust to be there, it can cause misfires, rough running and poor fuel mileage.

Brando56894 · 11-18-2005, 11:29 AM

ok, yea kasey lets just try to find anything thats screwed up, since we "supposedly" dont have to remove the cat, we can look at it in lot 6 inside of driving to your house, if we need to we can just go to johns house since its ALOT closer... or have him bring the tools here