ChevyChad

iTrader: (50)

I wasn’t sure where to post this, but I figured you guys in here would probably have a good idea as to what may cause this behavior.

Alright, so I just got my completely new setup installed. Forged LS6, Comp Cam (228/232 .581/.595 114+2), stock LQ9 heads with patriot gold springs and HS 1.7 rockers and chromemoly pushrods, new fuel system with dual pumps and 60# Siemens injectors, and I put a smaller 3.4” pulley on my P-1SC. My tuner did an initial conservative mail tune for me to get it going. He’s very experienced with these cars and has tuned hundreds of them. He is coming into town today for my dyno tune appointment.

Now for the symptoms: I finally got it started up. It idles a bit choppy, but I am just assuming that is because of the cam. So I didn’t think anything of that. Well, once it got up to temp, I took it for a drive and it ran like **** It sputters, backfires, pops, etc-doesn’t feel like it has any power (my pig H2 feels faster than it), dies sometimes when coming to a stop. Just plain nasty. All the grounds are good, all the fuses are good, all the wiring is connected. I hooked up my preditor hand held to it and checked the O2 sensors, and they were switching around at idle. All the sensors (MAF, MAP, etc. etc.) worked perfectly fine when I took my old setup apart.

Now the only problem I had when putting it back together was that apparently 2 of the wires in the crank position plug had come out. It would not start at all until I figured that out and soldered them back in. After that, it started right up. I am 99.99% sure the wires are not loose at all now, and they are making perfect connections. (They’d have to be right? Or it wouldn’t start again…)

Does anyone have any idea of what may be causing the car to run this way?

98SS1LWEE

iTrader: (25)

okay, same problem here, had serious y-pipe knock issues, but still not the full cause. anyone who wants to chime in on this one, you would have two grateful people

txhorns281

iTrader: (12)

Experienced or not, no way a mail order tune can nail a ballpark for your kind of setup every single time. Give your tuner an opportunity to clean up, I'm betting the mail order tune isn't even close

ChevyChad

iTrader: (50)

He has done similar tunes. In fact, he just recently did a procharged C5 with those same injectors a month ago. My brother thinks it may be missing due to lack of spark due to the backfiring thru the exhaust. It also is a bit hesitant on throttle response... We'll see if its the tune here in about an hour. I'll report back our findings...

Jrp1978

iTrader: (10)

There is no way in a one chance setting the mail order is gonna be right!
You have way to much stuff done to get a mail order. Go hopp on a dyno and make 550 hp for us would u! Just go get it tuned man They spend most of the time tuning just on cold start and get your maf tables right! There is no way to do that just by telling a guy what you have . OHHHHHHH little side note hope you are running a stock maf sensor 2 . (with the screen and not ported) you will never get that car tunned with a ported descreened maf! trust me i learned this first hand monday!

98SS1LWEE

iTrader: (25)

It's not the tune, i took my to get tuned, it's retarding the timing. Do you have autotap or anyhting? If so, you'll see, but why is the question. I know the backfiring and missing you speak of, try three quARTER THROTTLE THROUGH FIRST AND SECOND AND SEE IF YOU CAN GET IT TO CLEAR UP? DON'T GO wot

ChevyChad

iTrader: (50)

Well, it turned out not to be the tune. It was the rocker arms! I babied it to the dyno, and we did some logging, and all the sensors were checking out fine. He thought the rockers were unusually loud (They were harland sharp 1.7 non adjustables). So I went back home and put the stockers back on. Upon doing so, it came to my attention that about half of the ones on the passenger side were loose! One of the bolts was even broken! But just so you guys know, the tune was fine, and did exactly what it was supposed to do: let me be able to drive it to the dyno for a tune. And it did that very well once I got the rocker issue fixed. Anyways, we got it all tuned and running great now Thanks for the input guys.

98SS1LWEE

iTrader: (25)

Dude, you may have saved me some serious anguish and pain, i'm checking mine today, if you fixed my car for me, i will give you a free blinker fluid level indicator. No, seriously, i'm so excited, i'm checking this afternoon.

brad8266

iTrader: (23)

If you need help with your car let me know im local.