Just finished dropping in the new motor.
LD9 bottom, bored .020, new pistons and rods, 2.3 oil pump.
086 head, HO cams.
MP62 SC, LS1 TB.
OK, first start. The thing took a few minutes to calm down. Never was able to let it run since the RPM's ran up so fast. Like WOT.
Is my GMSC reflash not able to handle the new set up? I thought it would at least run until I got it tuned.
I kept the old SC injectors and same cold plugs.
Could I maybe be missing something like the IAC needing to "catch up" or this most likely a tuning issue? I don't think there are any huge vac leaks.
I figured this would be about the only place I could get an answer to this.
Labrat
If it is revving up id be looking for a vac leak first.
^^ x2
black 03 z24 with a few mods
Make sure the throttle cable isn't pulling the LS1 TB open at idle. Even just a little with that big of a TB can make a difference.
"Oil Leak ? What oil Leak ? Oh, Thats Just The Sweat From All The HorsePower!!"
all these suggestions are good things to check.
FU Tuning
^^That.
But seriously, the stock computer can only compensate so much. If you change anything that will affect the volumetric efficiency of the engine you will need a tune. The ECU is programmed to adjust to the normal operating conditions of a stock engine (like differences in IAT and octane of pump gas). Cams and a free-er flowing head would require a tune to maximize your mods. It may run OK once you fix the vacuum issue but youre never going to maximize the potential of what youve done,
The LS1 TB needed modified. I had to cut out passages for IAC and vac. Turns out there is a wide open passage around the throttle plate which I missed. Closed that off but still idles too high, but much lower than before. I'm gonna swap out the IAC with my old one. Hope they are the same part.
Thanks for the help guys. Getting there slow but sure. I am dying to try out this set up. Hope to be back with news she is running right.
Labrat
I found a few things. Placed o-ring for IAC (forgot it, doh). Plugged hole in TB plate. Still won't idle below 3000 rpm.
Looks like IAC is pulled all the way open. I've had it off several times and it doesn't look like it has moved. Any way to check operation of IAC? The old one is slightly different so I don't think it will interchange.
Labrat
Labrat wrote:I found a few things. Placed o-ring for IAC (forgot it, doh). Plugged hole in TB plate. Still won't idle below 3000 rpm.
Looks like IAC is pulled all the way open. I've had it off several times and it doesn't look like it has moved. Any way to check operation of IAC? The old one is slightly different so I don't think it will interchange.
I know with HPT you can watch the IAC stepper values.
FU Tuning
Just to let you all know. The VSS wiring was bad. Caused the p0502 code, went open loop and revved very high. Looking to get it tuned as it has a pretty rough idle, sounds smooth at higher rpm.
I wish I would have checked the slave as I now have a brand new slave leaking out the bottom of the tranny, grrrr.
Thanks for all the suggestions and help. This has been a pretty big undertaking for me. I'll be back with a progress report. May get my kid to take some pics to post.
Labrat
I have the idle and codes issues fixed. I now need to tune the beast. Not having any much luck finding a shop or tuner so I think I will try myself.
I have been researching "wide bands". Looks like "innovativemotorsports LM-2 might be a good choice. It looks like A/F and timing can be adjusted with the included software. Does anyone use this or have any input? Gonna order in a few days and hope it will do the trick.
Thanks
Labrat
you've had all these mods and never had a wideband on your car? you brave man, you brave! lol
a good tuner wont touch your car without a wideband on it anyways
04 Cav. 2dr. 5spd. My DD. 'Nuff said.
I have a LS1 TB also but ported
Fast idle at 1100 rpm..
Plug the hole in the throttle blade I got 900 rpm
But later my IAC failed and got 4000 rpm... It was an old IAC from a junkyard
In HP tuner the desired IAC position was about 18 and the IAC position was alot higher
The screw in the IAC was broken
I manually pull the IAC and put it in place and not connected and the car idle but in cold operaration have to hold throttle pedal a bit
blu04DD wrote:you've had all these mods and never had a wideband on your car? you brave man, you brave! lol
a good tuner wont touch your car without a wideband on it anyways
Not brave, just a lot to learn. The car was set up with a GMSC M45 with factory tune. It all worked great so I turned the key and drove. Now I understand the need for tuning on a custom set up. So far the new motor has only been driven a few test miles.
I believe I have the LS1 TB dialed in. I also plugged the hole in the plate. My problem was more with air leaks in the adapter and manifold.
Thanks for all the input, I am sure I will have more questions as I move forward.
Labrat
How did you plug your LS1 tb?
Im using the Vortec tb (73mm vs 75mm LS1) with the LS1 butterfly, since the Vortec butterfly has an air foil on it and it was easier to just swap (i have both tb's) vs grinding the rivets off and removing the foil. Plus the Vortec has a much better throttle wheel position and doesnt pull on the cable nearly as bad.
the only thing is the idle is a bit higher due to the hole in the butterfly. Im trying to think of a proper way to plug it without potential damage from it coming apart and entering the blower. my idle is set at 1050/1100, i like it there.
And yeah its all a learning process. Fortunately theres a ton of experienced supercharger peeps here that can give quality advice based on hands on experience. Im learning every day...not always by choice lol
04 Cav. 2dr. 5spd. My DD. 'Nuff said.
blu04DD wrote:How did you plug your LS1 tb?
I used a 1/4 inch bit to drill a funnel shape, then filled with JB Weld. I will weld it if it fails but it's holding up fine so far.
Labrat
Finally got the wideband and HPT hooked up yesterday. Readings were lean under all conditions. Moved the fueling table up. It will now idle smoothly at 1000 rpm setting. At idle and under low load conditions it will throw a p0300. We monitored each cylinder and none were reporting any misfire. So I may have one of those "ghost" misfires that seem to pop up with more aggressive cams. Hoping not though. Gonna do more searching to see if timing may need some work.
The car runs well with RPM's above 2000 under laod. I did do a 3rd gear pull while recording and motor pulls strong and does not misfire. She really breaths well at 4500 to 6500. I have not raised the limiter yet, not gonna push it for a few more miles. I guess I may have to learn how to drive this new set up as the LD9 has reasonable torque whereas the HO had more top end.
I have to fix a PS leak. AC is out too. Dam, more money going into he pit. I am going to start driving it daily so I will have a better feel of what is normal or not. Thanks for all the help so far and I am sure I will be back looking for more answers.
People keep asking me "why the SEG", they just don't understand.
Labrat
