ss.slp.ls1

iTrader: (36)

I just installed a new LT1 w/ a cc503 cam and headers. I have 12" of straight pipe off of the headers temporarily until I get my y-pipe put in. I have a mail order tune from MadTuner.
The car starts up fine, idles fine, just doesn't have any power when I get on it. I have been given a couple of suggestions:
a) Fresh air hitting o2's causing a rich condition
b) Open headers causing false knocking which in turn pulls timing
No codes present.

Ok, now to the real purpose of this thread...if I unplug both the knock sensor and the o2's will that be sufficient to test if either/both a. and b. are the culprits to my lack of power? I also heard that I can remove the knock sensor module from the pcm so that no timing will be pulled.

Elliott's94Z

iTrader: (12)

What exactly is it doing when you try to excel? Is it surging?

ss.slp.ls1

iTrader: (36)

No, it just feels like its hesitating/missing.

Elliott's94Z

iTrader: (12)

Not saying this would be your issue but I have seen guys run larger cams like the 503 with the stock stall and no gears and they were having the same issue you are experiencing

ss.slp.ls1

iTrader: (36)

I have a M6 w/ 3.42's so I doubt that's the problem. I am going to try some stuff out today after work.

xx_ED_xx

iTrader: (17)

valves adjsuted right do you have compression??

ss.slp.ls1

iTrader: (36)

I didn't test for compression. I adjusted the valves when the motor was being assembled. I used a pencil to determine when #1 was at top dead center and adjusted half of the valves, then rotated the motor 360 and adjusted the other half.
I could try to do the engine off method. Wouldn't that be just backing off each poly lock, slowly turning it till it stops, then added the preload and seating the allen screw?

borninatransam

iTrader: (4)

When I first finished the 383 I was running open headers for about 3 weeks with no issue. Never had an O2 go out and didn't get any false knock. Not saying that you couldn't have an isolated incident but I would look to a plug wire laying over on the header or maybe even not hooked up. Could have the plug wires plugged up wrong too. Just double check that stuff first.

ss.slp.ls1

iTrader: (36)

I will be double checking the wires today. I put Accel heat boots on them so that they wouldn't burn. I have never hooked wires up incorrectly before, but there is a first time for everything, but I would think that I would be getting a misfire code if there was a problem with the wires.

ss.slp.ls1

iTrader: (36)

One question, will a compression test confirm that the rockers are adjusted correctly?

Also, I added 1/2 turn of preload, not 1/4, is that bad?

Chevyguy358

iTrader: (4)

yea a compression test will tell you if the rockers are too tight, if so they will bleed off pressure to that cylinder. or just go back over the adjustment running

ss.slp.ls1

iTrader: (36)

I hooked up an Auto Xray scanner to my car and drove it around a little. The car was running worse than ever.

The o2's were fluctuating from .1-.9 at idle
Long Term fuel trim was 25%
Map sensor at idle was ~11 in.Hg.
Ignition timing at idle was ~25*

Ignition timing under load was 30-45*
Map sensor under load was ~30 in.Hg.

I didn't have anymore time to get more data, it was getting dark and I didn't want to get my car impounded.

I am going to check the wires and maybe change the opti soon.

AChotrod

iTrader: (17)

Is this just in the low end or all the time? You totally have to change your driving style or else the car will buck/stumble at low RPMs.

ss.slp.ls1

iTrader: (36)

The car won't go at all. I brought the rpms to 3500 and step on it and the rpms just struggle to rise as the car is stumbling/missing. It's pretty bad. I am hoping its just something simple like a distributor or wires. I'll post when I try new things.

AChotrod

iTrader: (17)

are you sure the opti is on right?

ss.slp.ls1

iTrader: (36)

Positive. The new engine was so clean, I assumed the opti that came with it was ok, but I am suspicious of it now and I am going to be swapping the AC Delco opti from the old engine w/ only a couple thousand miles on it, cause I know it works.

Formula350

iTrader: (3)

Plug wires on right? Wouldn't fresh air hitting O2s = lean, even if it WAS happening (which I doubt)?

Injector wires on correctly? They're specific on motors newer than 93, since 93 is batch fire and the rest sequential.

From what you're saying, is it correct in assuming that it's been MAP tuned for !MAF? Or was MAF intended and MAP was a typo? I'm just thinking that if it was MAP tuned that possibly it was, although not as likely, not tuned properly. Not sure how the OBD2 systems look, but for my ECM car (my 91 TPI and 93 LT1 are virtually the same) it has 2 Volumetric Efficiency tables you adjust; 400-2000rpm and then 2000-7000rpm. So if it's too high or low, then I could see that possibly causing those problems.

Sadly though, all my tuning is only from what I've read. I've only been able to do 2 chips, 1 for my TPI and 1 for my LT1, thankfully both turned out good. Yet I haven't been able to get a new chip burned (haven't found anyone) so I can't run one of my updated tunes

ss.slp.ls1

iTrader: (36)

When I swap the opti, I will check the wires and the injectors, but I'm sure they are on right.

SoxXpupPeT

iTrader: (34)

yeah def check the opti. sounds similar to my dads car when his opti crapped on him. its abit involved but its worth a shot. might wanna pull your timing chain cover to to make sure everythings good in there

Formula96

sounds to me like over tightend rockers, mine did the same thing after i put new head gaskets on, took me forever to get the rockers tightened down right...