Ok heres the situation Im currently running the 847 cam on stock heads with several bolt on's. I was having a problem with a high idle & high idle code P0507.. Did some searching and checking to find that there were 2 holes drilled in my Tb blades, I contacted the tuners of the vehicle to get a explanation on the holes and was told it was to help the car idle. I decided to plug the holes to see if there was a difference and i found the code hasent returned in 200 miles and the idle has been normal without any 2k burst like before. Well if i let the car sit for 3 days it won't fire right up and run at the desired open loop idle (1063 rpms) it will start off running around 500-600 rpms and i have to give it a little gas to keep it running within it's desired rpm range, Now if i fire the car up everyday as if it's my DD it will fire right up and run like a champ.

Do i need the holes in my TB blades to keep the car running like it should after a couple of days? Or is there something that can be adjusted through the tuning? Im running a holley 58mm tb with a ported intake to match the car has been dyno tuned so any input on the situation would be great i've never heard of needing holes drilled in the tb blades to help aid in idle on the 847 cam So im lost here. Below are some other things that i noticed and logged after plugging the holes. Readings were taken in closed loop with the coolant temp @ 180 after 15min of idling.

Heres the reporting with the holes open

IAC position 0

IAC memory 10

Desired Idle 900

Current idle 1163-1220 (jumps around)

Maf 8.60g per second

Tps volts 0.69

Tps % 0

Engine Load 6



Heres the change i reported after blocking the holes

IAC position 67

IAC Memory 41

Desired Idle 900

Idle 864-913rpm (Jumps around but within a better range then unblocked)

Maf 9.02g

Tps volts 0.69

tps % 0

Engine Load 3

I spoke with Ion and he recommended me posting here to see what others had to do out that and to see if anyone had any input or recommendation on the situation.

 

When you start it after sitting for 3 days:

-is the cranking (starter turning the engine, but no fire) time extended compared to your "less than 3 days" start?

-when it finally fires, and you have to keep your foot on it to keep it from stalling, how long does this last?

-when its running at 500rpm and your diddling with the throttls, what are the IAC counts? Is there any sign the PCM is opening up the IAC to control the idle?

-does the coolant temp sensor show the correct temperature when you try and start it?

-what are the values in the cold engine idle table for RPM vs. coolant temp?

 

Thanks for the reply Injuneer

The Engine will fire right up but only idle around 500-600 rpm, it doesnt have a hard time cranking and usually catch on the first time.

It usually last for about 5-10 seconds then the car will run on its own.

I don't have any Iac counts after trying to start the car for 3 days, but when i fire it up daily the pcm commands the IAC to about 130 counts KOEO then when i fire it up it goes down to 127 (desired Idle 1088) then it drops to about 92 and then slowly drops as the car warms up. When desired idle goes to 900 the counts go between 67-72. So by those readings when i drive it everyday to me it looks as if the IAC is being commanded by the PCM and it's responding. (if that helps)

I can only assume the temp is accurate.. My scan tool reads the temp being 90 degrees in a 80 degree morning, The lowest my autometer gauge goes is 100 so i cannot accuratly gauge it's temp below That.

I don't have those last values, Im only using a Solus snap on scan tool to get these readings. I don't have LT1edit or anything like that sorry.


The car is parked so i will get those IAC readings when the car barley wants to idle by friday morning Before i change the plugs.