00Corvette

iTrader: (1)

Guys,
I've just put headers on my 00 C5 with a vararam and then sent out the PCM for a tune.
Ever since I got the computer back from the guy, the car just hasn't seemed to run quite right except for a little while after I pulled the PCM fuse and then put it back it.
It kept throwing a code saying knock sensor circuit(or something). So I replaced both knock sensors and I replaced both front O2 sensors after the header install.
Now even after putting the new knock sensors in(old ones had no oil or water signs on them what so ever) the code came back a couple of times and now it's also throwing a P0127 and one more code that I can't remember but they both say "rich fuel bank" or something to that effect.
Would there be any benefit or harm to trying to run the car with the MAF disconnected to see if maybe that's why the fuel trims are off???
It just seems as though the computer is retarding the timing a few degrees?
Thanks for any help,
Donnie

300bhp/ton

unless you are running a SD setup you need the MAF to tell the PCM the airflow so it can add appropriate fuel, without it, it simply won't have a clue.

As all these issues seemed to appear when you got the PCM back then logically it's probably one of two things:

1. The PCM is damaged (blowing fuses is not a good sign)
2. The tune is *****, next time send the engine along with the PCM when you get it tuned.

BLKWS.6

[QUOTE=300bhp/ton]unless you are running a SD setup you need the MAF to tell the PCM the airflow so it can add appropriate fuel, without it, it simply won't have a clue.

As all these issues seemed to appear when you got the PCM back then logically it's probably one of two things:

1. The PCM is damaged (blowing fuses is not a good sign)
2. The tune is *****, next time send the engine along with the PCM when you get it tuned.[/QUOTE]

+1 you have a vette, not a buick skylark. Go get it dynotuned!

BirdmanLS1

iTrader: (3)

Hey hey... thats my beater you are insulting!! skylarks pwn...

NoGamesLS1

iTrader: (16)

The fuse didnt blow. He just pulled it and put it back in to see if the PCM would reset and take the new tune. I agree that a dynotune is the only way to go, but by the same token his only mod is longtubes and a vararam. So it should be easy enough for a mail order tune. But back to the problem...any ideas? Did you look at your maf to see if there was any oil built up on it?

staringback05

iTrader: (8)

honestly....your car will run....it was actually designed not to fail, just because the maf fails....for example...to take a maf out of a explorer...that bitch wont run period....but our cars...itll stumble along, i wouldnt do it for any length of time though

00Corvette

iTrader: (1)

Guys,
Yeah the fuse didn't blow, I was just told that if you pull the PCM fuse out for a couple of minutes it'll reset the fuel trims possbily curing the problem??
To the guy that send next time send the engine....I'm actually working about 70 hrs a week right now and the closest reputable shop with a dyno is about 7-8 hrs away. So it's not just like I can "run down to the shop and get it tuned".
Thanks for the help on the issue though, I guess I'll try another tune but I think I'm going to check the connector for the knock sensor's behind the intake manifold...has anyone ever had any trouble with that connector?
Thanks again,
Donnie
P.S.Check engine light is on again!

3.4camaro

iTrader: (1)

unhook both battery terminals and touch them together. that will immediately reset eveything. you might not have had the fuse out long enough.

the PCM has capacitors inside it so it can keep fuel information without power. But if you touch the terminals together, the capacitors exert all of their charge.

go give it a shot.

00Corvette

iTrader: (1)

Please...are you serious??? I actually had the fuse out for about 2 hrs last night and still have the same problem...I think I'm gonna try another tune.
The sarcasm on this site is crazy, someone asks a simple question and can't just get a straight answer...
I mean maybe the mail order tune idea isn't the smartest but come on...call it a learning experience. The guy that I had tune the car came very well recommended on the corvetteforum and to be honest I talked to about 6 or 7 guys personally who all had excellent results from his tunes!
I'm more inclined to think that maybe the guy just bumped a key twice or something but just to be safe I'm gonna have the car tuned by someone else here really soon.
Thanks again,
Donnie
P.S>Steve(Nogames)What's up man?

5550racing

Maybe if you have a dealership in your area they could reflash your PCM. I don't know a whole lot about tuning but when they reflash it wouldn't that reset it back to the factory tune

You would probably get a better awnser if you put this question in the PCM and Tuning section.

3.4camaro

iTrader: (1)

yes i was dead serious about touching the terminals. get rid of that charge and your problem might go away. just trying to help.

i go to www.pbnation.com forum to be a sarcastic dick, but not here!

00Corvette

iTrader: (1)

3.4,
Sry, thanks then man. So, how long should I touch them for? Just a tap or...? 2 seconds?
Thanks so much,
Donnie

300bhp/ton

I see two other options.

1. Speak to who ever you got the tune from.
2. Buy yourself something like EFI Live or HP Tuners so you can see what's actually going on and can reset the tune if needed.

VIP1

That sounds like a really bad idea. Where is that spent energy gonna go? It doesn't just poof and disappear. It probably gets absorbed by another electrical component.

00Corvette

iTrader: (1)

Guys,
Thanks again for the help. I actually did talk to the guy that tuned it and he just said that the knock sensor code probably wasn't caused by the tune and told me to just pull pcm fuse for a couple of minutes and let it reset then see what happens. After pulling the fuse and letting it sit, it ran good for a little while but then the code came back...then I pulled the intake manifold and replaced both knock sensors but the old ones didn't even look bad. No water or oil down in the holes but I replaced them anyway. After replacing the knock sensors the light just came right back on after a couple of miles and the car just doesn't seem to run as strong as it did even before the tune to be honest.
Then I pulled the fuse out again just to make sure that it got a chance to reset after the knock sensors but I disconnected the negative on the battery before changing them anyway. After all that another code(s) came on and they had to do with the "banks running lean" P0127?? P0125 I think??
But those two "lean bank" codes haven't come back on since that one time and the knock sensor code is still there but it stays as a history code and doesn't actually throw the light?

VIP,
Thanks man, that's what I was thinking too but I didn't know if the guy was serious. I just thought it would hurt something by touching the terminal's together.

Oh, I would buy the hptuners software but I really don't have the knowledge to use that stuff and don't have the money at the currrent time. Also, really didn't think that the tune would be so difficult to do with just headers and an air intake?
Thanks again for all the help,
Donnie

VIP1

I was reacting to the comment of discharging the capacitors. I'm no electroical engineer, and I may be over-reacting, but they way it was described sounded like a bad idea.

NoGamesLS1

iTrader: (16)

A capisitor lets out a good amount of power. I wouldnt want to see it fry your computer. Hey Donnie have you asked Cody? He might be able to help point you in the right direction or let you know if touching the terminals together is a good idea. If you dont have his number his s/n is ls1_doc. Shoot him a pm, Im sure he'd be happy to help.
-Steve

CRAGER

You're not going to pull a tune out by touching terminals or any kind of rain dance or anything. You have to pull it out with tuning software.

+1 to have it flashed, OR see if you can find a stock PCM to slap in there and see if its the tune.

If lean check for vacum leaks, or exhaust leaks. Can't think of why your knock sensors are acting up though, sorry.

Peace,
Craig.

VIP1

It depends on the size, but yes...hence my reaction.
Don't mess with the large capacitors in a PC power supply.
Where is that electrocuted smiley when you need it?

ls1_doc

iTrader: (6)

Good advice. I Would figure out why you have the lean code first. Is there any rattles in the car from the headers? Maybe sending false knock?