So ive been getting the new engine going and ready for some retunes. I have had some issues up til this point and have made some ground. Ive fixed a couple vacuum leaks and pretty much ruled out exhaust leaks.

My long term fuel corrections went from being maxed out at idle on bank 2 to being maxed out on bank 1(over the last day or two). I dont know if that common or not.

I have used both propane and starting fluid to test for any other leaks. Didnt change anything either(possibly moved wires). I reset the pcm and drove three or four days(30+ miles per day) then logged and two days later the split is now on the other side. Once it gets out of that cell(16) things come back together.

I do plan to do some playing with the throttle body(one of the mods for split blm and idle) as well as check voltage of tps and those things ive read about.

Tb is 58mm tpis and I have the nitrous plate behind it so ill have to look things over and then try and pick the mod that looks like would work best. My cam is just a little bigger that cc503 on 112 lsa.

Im learning more about what to look at on datalogs but still havent masted the use of the (dreaded) ftp lol. Thanks for any imput or advice. Mostly wondering if its common for the swap of the split blm.

 

Are we dealing with the engine in your signature?
What kind of sealant did you use to seal the intake?
Did you use sealant on the rocker studs(the side of the stud in the head)?
Has the PCM been reprogrammed for the new engine?
Which way are the trims maxed? Positive or negative?
Does it idle "ok" or does it need throttle to idle?
Do you have the stock throttle body? The one you have could be to blame for the split trims....I'm not completely sure on that, but I do know that many aftermarket throttle bodies cause split trims.

I haven't put together a 383 yet, so we may need for others to chime in on the topic. However, answering the questions above could help us hit on something.

 

Intake sealant I either used a good copper sealant or the black sealant(both were having many recomendations on here and other lt forums) I had it off a second time and dont remember which I used first and or last.

I didnt assemble the top end, although I repulled motor and had to seal all my headstuds as builder used teflon tape and had several seaping with no coolant pressure. Please tell me about this as after i eliminate a few other causes I may just pop the valve covers and reset my valve lash.

Yep pcm is programmed for current mods(in signature)

Im guessing the trims are positive (still a total noob -rookie - dont know much at all lol) I will try to link a log with the split each way as i think i got that figured out.

It idles without trouble or help. Its like if you count 1,2, then at three it gets rough then smooths and repeats.

I do still have the stock throttle body and I am assuming the tpis58 mm thats on it is probably a big part of the problem.

 

https://docs.google.com/file/d/0B1bD...pUM3ZjLVE/edit
https://docs.google.com/file/d/0B1bD...1MTjhUUVE/edit

perhaps those will post. one should show the bank one being maxed at times of idle and the other the bank 2.

I plan to do something of the tb mod, check both sides o2 wires for any burns. Probably check at least all 4 plugs on bank 1 as I did pull 1 and 3 and 1 was rich and 3 was lean(passenger side has same temps with ir thermometer so may be the same) I also want to ohm my plug wires even though 12inch and less i may have damaged something when I was forcing boots on as they are cut to fit.

 

What logger did you use to generate the data logs. I am not familiar with the ".lgf" file extension that you posted. Have no idea how to open it.

 

ecmpro scan. Im definately no help but I sure appreciate your efforts. I had to import it to the ecmpro scan to open it so it might be limited who can view it. I have a few minutes before leaving so ill look to see if i can see something in the settings that might help. Thanks

 

Update?

 

Update......, I pulled throttle body and compared to stock. The design just dumps the idle air in the plenum and doesnt allow for use of the iac passages in intake manifold. I also noticed my nitrous plate restricted this opening even more(1/4" hole). I looked around shop for something to connect the throttle body to the iac port on manifold. A 300 weatherby magnum casing fits snugly in the hole. I cut and shaped that and drilled the nitrous plate to 1/2" to reciece the brass tube. I had a very slight alingment issue so I had a 30-06 casing and it fits nice inside the 300 casing. I put a skim coat of silicone on that assembly to keep it all in place and tried it..........,....................,................ .......................... that helped alot but still not what I was looking for. I then began to drill the hole through the front of tb into the iac( like stock tb) I started with stock size hole and drove for a day with each size hole. I ended up two sizes larger drill bit than stock hole(1/16" over my stock size through hole)......... I dont care to go any larger than that as I feel that should accomodate for the extra cubes of motor and greater needs........................................... from the begining I have been questioning my iac valve(motor) as it sticks and hasn't seemed to work consistant. Ive tried the reset several times and have cleaned the pintle. What I have noticed is as the pcm adjust the iac memory it effects the fuel trims. I let car idle for several minutes a few different times and eventually the trims balanced out at an acceptable level. Last night was the first time the iac seemed to work correct but the memory was so high I didnt have time to let the memory stabilize......................................... before I did the mod to tb ive looked at all plugs. In each bank I have 2 very good looking and one bank had 2 rich and the other bank had 2 a bit lean. I will be looking soon to see if using the iac passages now has helped this. On both sides it was the front 2 that looked good.