Engine runs, but idles too high?? Not a Vacuum problem, Tuning issue?
Hi guys. New to the site, and new to tuning and looking for some help. I recently started up my project after doing my LS1 swap, and now it won't idle under 1200? I am unsure if it is a tuning issue or a simple vacuum leak. I haven't had enough time to out rule the vacuum leak, but wanted to see if anyone could point me in the right direction.
Background on the car: 1976 Pontiac Trans Am, that I recently have swapped in a 1999 Camaro LS1 and t-56. I modified the wiring myself with lots of help online. Other than the LT headers and a CAI the engine itself is stock. I plugged the egr hole in the intake with an expandable rubber freeze plug as a temporary solution until I can buy an LS6 intake. All my gauges are fully functioning and the only real issue I am having is getting the car to idle properly.
I deleted the EGR, AIR, EVAP, Rear O2 sensors and I thought that I read all the proper ways to disable them from my tune. Essentially what I did was changed the egr to disable, and for the rest unchecked the boxes for the codes to be thrown. Is that all I needed to do? The reason I ask is because under DTC's EVAP is a code that keeps being thrown, but I unchecked it.
I am at work now, but I can upload my tune later if someone wanted to look at that.
Here is a link to my build and on the last page is a video of it running from this weekend.
Ok, so I went through my engine this weekend, and looked for vacuum leaks by spraying around the intake with starting fluid. I didn't get any increase in idle on any of the vacuum ports. I especially sprayed where I blocked off the EGR port, but didn't get any leaks. I will upload my data log and tune from this weekend for someone to take a look at to see if they can help me out. The one thing that I see that could be problematic is at idle I am 20* advanced in timing? Not sure what is causing it to be that advanced?
I did have the intake off in order to clean all of the grease and grime off the car. I sprayed all of the vacuum ports with starter fluid, and it didn't raise the idle at all. I took off the IAC last night and cleaned everything and reinstalled. I also took the throttle body off and pointed it towards the driver while turning on the key. I verified that it was working and moving back and forth. I am unsure what the position should be at start. It was slightly cracked allowing more air to the intake.
While I was doing this all, I remembered someone saying that they plugged the hole in the throttle body blade. So, just to test it out I put a piece of tape over the hole, and it worked! The idle went down to around 850 where it should be. Although it worked, I don't think that it is the right solution. The car in the donor had no idle issues and I am thinking that it is a tune issue at this point. The only thing that I can think of is that because I am running no filter currently and 1 7/8" long tube headers, the MAF calibration needs to be adjusted since it is flowing much more air. Can any one verify that?
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