Could I have a bad tune?

[GradeZ28]

I hope someone can give me some suggestions here..

since ive got my tune (pcmforless), at throttle my car runs AWESOME... but in normal driving i have a few issues that are starting to really get on my nerves.. first off, ive been running pretty rich and whenever im cruising at a steady speed and i just barely push down on the gas, it will randomly cutout.. this happens at all speeds and so ive gotten used to letting the speed drop to 1mph below, then giving it gas to go 1mph above, then letting it drop... and so on

Yesterday I got stuck behind a semi on the freeway that was slowing down to turn left.. there were a few cars in the right lane and as soon as i got a chance, i put it into first and gave it about 3/4 throttle.. my car started jumping/falling on it face (like GO, dead, GO, dead, GO, dead).. so i let off, put it into second, and ease into the throttle and it still does it.. i put it into neutral, rev it up and then put it back into gear and it drives fine for the rest of the day.

My thoughts are that its:
1. bad tune. Im pretty sure that pcmforless didn't actually even modify my tune file, rather they just sent me someone else's with a similiar setup because the shift tables were all out of whack, and some of the specific settings i had were reverted to stock (I had sent them my stock file with some of my small changes and asked them tune that file).. like i said though, it runs great at full throttle, but normal driving.. not to good.

2. bad 02 sensors

3. throttle sensor is messing up

any thoughts?

[Mean Green]

sounds similar to a problem I'm having. do you have some data logging software? if so, what are your o2's reading?

[GradeZ28]

Originally Posted by Mean Green

sounds similar to a problem I'm having. do you have some data logging software? if so, what are your o2's reading?

I do, however either my laptop or my data cable doesn't like to work well with it.. they will do pcm burns fine but when it comes to data logging, it like times out or loses connection every few seconds, and the records it does get, usually has errors so there no telling which information is accurate or not

[Mean Green]

hmmm....I'm thinking o2's are most likely the culprit, but it would be nice to know before just going out and buying new ones.

[rolemodel]

Sounds like bad readings from 02's or misfires

[BlackY2kZ28]

sounds like a bad tune to me possibly

[titter]

what datalog software are you using? a good log file will help a ton!

[GradeZ28]

I have that one free one (i forgot what its called.. freescan?) and also datamasters... both have trouble keeping a solid connection.. i need to get a different laptop and/or a new cable to hopefully be able to use them

[Mean Green]

does your laptop have a USB port? if so try using an RS232/USB adapter. I've seen more than a few RS232 ports go bad on laptops.

otherwise ask around the local camaro community and see if someone will let you borrow/rent a cable or laptop.

Also use Datamaster to record the log. Although I like using PCM Communicator for watching things in real time (larger font and layout is easier to read)

[GradeZ28]

Yes it has USB, and the cable is RS232.. I actually did buy a rs232/usb adapter but it didn't work.. afterwards i read that only belkin's adapter works for some reason... ill have to buy one of theirs and give it a try.

Do you have a link for PCM communicator?

[Alvin@pcmforless.com]

Originally Posted by GradeZ28

I hope someone can give me some suggestions here..

since ive got my tune (pcmforless), at throttle my car runs AWESOME... but in normal driving i have a few issues that are starting to really get on my nerves.. first off, ive been running pretty rich and whenever im cruising at a steady speed and i just barely push down on the gas, it will randomly cutout.. this happens at all speeds and so ive gotten used to letting the speed drop to 1mph below, then giving it gas to go 1mph above, then letting it drop... and so on

Yesterday I got stuck behind a semi on the freeway that was slowing down to turn left.. there were a few cars in the right lane and as soon as i got a chance, i put it into first and gave it about 3/4 throttle.. my car started jumping/falling on it face (like GO, dead, GO, dead, GO, dead).. so i let off, put it into second, and ease into the throttle and it still does it.. i put it into neutral, rev it up and then put it back into gear and it drives fine for the rest of the day.

My thoughts are that its:
1. bad tune. Im pretty sure that pcmforless didn't actually even modify my tune file, rather they just sent me someone else's with a similiar setup because the shift tables were all out of whack, and some of the specific settings i had were reverted to stock (I had sent them my stock file with some of my small changes and asked them tune that file).. like i said though, it runs great at full throttle, but normal driving.. not to good.

2. bad 02 sensors

3. throttle sensor is messing up

any thoughts?

Hi,

maybe I can help.

What is done to the car. Do you have a modification list? Second, when did the problems show up? Immediately after loading the file or some period after.

[GradeZ28]

the main mods are:
cai
cc305 cam (114lsa, 224/230, .510/.510)
headers with true dual exhaust
ported & descreened MAF
1.5 roller rockers

The problem with it cutting out under partial throttle & running rich has been a problem since i loaded the tune (i didn't drive the car at all between the camswap and loading the tune.. both were done at the same time)... one thing that did cross my mind though, right after i did my M6 swap, (the battery had been disconnected for at least a week during this time), i was able to get 24mpg in the first couple hundred miles, so obviously it wasn't running too rich, but since then its gotten back down to around 16mpg and you can smell that its rich real bad.

The problem with it falling on its face only started recently (which makes me beleive it might be the 02s)

I did the email tune with you guys and i guess its my own fault for not getting it modified within the free 6 months to get it a little more stoich... perhaps i can pay you guys a partial fee to modify the low-load sections of the tables to try and lean it out a little? If you want to discuss price or whatnot you can PM me.

Or maybe I should just but some new o2 sensors first to see if that clears it up.. it sucks that they are $50 each though lol

[Alvin@pcmforless.com]

Try sending a datalog to bryan.. he may be able to spot something (hes the one that would have done your file thats why I'm refering you to him)

Just a hint you might try. The car should run, and run with otu cutting out or anything fishy like that on the stock tune. So one thing you can try in the mean time is load up the stock tune and take it for a ride.. If it does the same thing you should look over the car one more time.

I think utimately you'll find a burnt plug wire.. Thats what it sounds like to me and it will throw the fuel trims all out of wack.

[GradeZ28]

Originally Posted by Alvin@pcmforless.com

Try sending a datalog to bryan.. he may be able to spot something (hes the one that would have done your file thats why I'm refering you to him)

Just a hint you might try. The car should run, and run with otu cutting out or anything fishy like that on the stock tune. So one thing you can try in the mean time is load up the stock tune and take it for a ride.. If it does the same thing you should look over the car one more time.

I think utimately you'll find a burnt plug wire.. Thats what it sounds like to me and it will throw the fuel trims all out of wack.

Thanks for the tip.. i will load the stock tune and see how it runs.

what about fouled up plugs? Since ive been running so rich i already know my plugs are no good.. I will be putting a new set of NGK's in on Monday. I will also carefully inspect all my plug wires.

[Alvin@pcmforless.com]

Car misfiring, sending fresh o2 down the exhaust, car thinks its running lean, throws more fuel at it.. bam.. look where your at.