Idle hunting and stalling at "clutch in" idle (Cammed 13 GT500)
My first post here. I've come here looking for some recommendations/ideas on how to resolve a hunting idle and stalling issue I'm having after a cam install on my 2013 GT500. I've done some searching and have read through a couple of threads. This thread seems to be closest to what I am seeing: Current Mods:
http://www.hptuners.com/forum/showth...g-cams-no-idle!
Here's the whole story:
Car: 2013 Shelby GT500 (currently SCT Tuned)
Current Mods:
* 2.9L Whipple with 3.0 upper and 10% lower
* JDM Super Stock Camshafts
* Kenne Bell Competition BAP
* ID 1000 injectors
* FRPP Cobra Jet wide oval throttle body
* JLT big air 127mm Carbon Fiber intake
* Stainless Works 1-7/8" Long Tube headers w/ offroad x-pipe
* 93 Octane
Car was running great with the same mods above, minus the cams and lower pulley, prior to cam install. Had cams installed, and car idle hunted badly between 200-1200rpm when coming to a stop and frequently stalled. I even had the car go into limp mode twice after stalls and had to shut it down and restart it to clear limp mode. To restart it after it stalls, you have to floor it to let in more air, sorta like a flooded condition or it will just continue to turn over and not start. When I cold start the car, idle drops to about 300rpm, jumps to about 1500rpm then stabilizes at about 1000rpm then slowly drops to 775 idle after it warms up. I changed the MAF sensor, O2 sensors and Wideband sensors, swapped throttle bodies and checked for vacuum leaks and still no changes.
About a week after the cams install, I added the 10% lower and 3.25 upper to make up the boost loss from the cam install for a retune with the new cams. After installing the 10% lower and 3.25 upper (on the same tune) and prior to any tune adjustments, the idle hunting issue was reduced significanting. I went and drove the car, staying out of boost, and could not get it to stall when coming to a stop. I tried to make it stall by clutching in from high rpms and low rpms and couldn't do it. The idle hunting was reduced to between 500-900 and settled in at idle relatively quickly. This was very driveable to me and I could definitely live with that as long as it wasn't stalling. What I thought was, that the added blower speed at idle was helping air flow and basically fixed my problem.
Well, I did some idle/rev and cruise datalogging with the new cams for my tuner and received a tune adjustment. I loaded the tune the night before going to the dyno but didn't drive the car. The morning before going to the dyno, I had some time and disconnected my battery to install a battery cover. Well, on the way to the dyno, the car was idle hunting and stalling all over again. I couldn't attribute the tune change or battery disconnect to the problem because they were both changes accomplished before driving the car.
While on the dyno, I made an upper pulley swap to a 3.0 to increase boost on the same tune. The car instantly started running good again, starting up great with no idle hunt. We made one pull to 5000 to verify the A/F and clutch in idle after a short pull had minimal idle hunting again and didn't cause the car to stall. then made a fuel adjustment to the tuneand
After I loaded the new tune, the idle hunting and stalling was back. It seems like a new tune resest idle/air to whatever value my tuner has in the tune. When I make a blower boost adjustment on the same tune, the idle hunting is better.
The current tune made huge power 800/670, 16.5-17psi, 18deg timing, at only 6800rpm (new rev limit) and drives great, EXCEPT WHEN COMING TO A STOP! There's nothing more frustrating than driving a badass car and it stalling everytime you come to a stop.I have since converted to E85 and have the same problem. With the initial E85 tune, I still have idle hunting issues but not quite bad enough now to cause the car to stall but it comes very close. Any ideas you might have on how to correct this problem would be much appreciated.
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