TB changes, idle code
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TB changes, idle code I had my TB powdercoated and the epoxy around the IAC baked out, now my idle is high (it would seem due to the new lack of IAC restriction) and it threw a P0507 (idle speed high).
I have HPT. I need to adjust the RAF, right ? Use the histogram for RAF and apply the results to the Idle Airflow vs. Coolant temp table, right ?
Thanks,
Rob (Bad30th)
I have HPT. I need to adjust the RAF, right ? Use the histogram for RAF and apply the results to the Idle Airflow vs. Coolant temp table, right ?
Thanks,
Rob (Bad30th)
No that won't do it, but it will be required afterward... the issue is that the IAC cannot block enough airflow to get the idle down. Log IAC counts. Yours will be at 0 at hot idle now, and spark over-speed is still unable to hold the idle down because of the additional airflow. Back off the TB set-screw by about 3/4 of a turn to 'close' the blade up a bit further. Check IAC counts at hot idle. If they go low after idling for a few minutes at temp, then you need to close the blade more. Once you get the counts in range, use your idle airflow histo from cold start to arrive at a new idle airflow table.
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Thanks. So it sounds like the immediate problem is more of a mechanical issue with too much air getting past the TB...
I'm pretty sure the TB blade is closing all the way, but I'll check to see if adjusting the set screw helps... I know the TB blade also has a hole in it, but it was running perfect before the epoxy baked out...
What do I do if the blade is closed all the way and adjusting the set screw doesn't change the IAC ?
I suppose I could try to fill the TB back in but I'd rather find another way around this...
Thanks,
Rob (Bad30th)
I'm pretty sure the TB blade is closing all the way, but I'll check to see if adjusting the set screw helps... I know the TB blade also has a hole in it, but it was running perfect before the epoxy baked out...
What do I do if the blade is closed all the way and adjusting the set screw doesn't change the IAC ?
I suppose I could try to fill the TB back in but I'd rather find another way around this...
Thanks,
Rob (Bad30th)
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Took a quick look at lunch today, the set screw got "adjusted" at the powdercoater and is at least 1/8" up off the bump stop. 
I will drop the set screw and that should straighten things out considerably...
Thanks !
Rob (Bad30th)
I will drop the set screw and that should straighten things out considerably...
Thanks !
Rob (Bad30th)
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Well, solved the giant "vacuum leak". I lowered the set screw back to almost flush with the bump stop, and plugged the TB blade hole with a tiny bolt/nut and used red loctite & tightened the crap out of it, then used a dremel cutoff to take the rest of the bolt off flush with the nut. It doesn't obtrude into the airpath more than the other bolts, so good enough for now...
I just don't want that little bolt coming loose and trying to find its way into a cylinder.
I may try to find another TB blade anyway for peace of mind, but problem solved for now, started and ran like a champ with no high idle.
Apparently a clean unobstructed IAC path is plenty of air at idle for an LS6 cam.
Rob (Bad30th)
I just don't want that little bolt coming loose and trying to find its way into a cylinder.
I may try to find another TB blade anyway for peace of mind, but problem solved for now, started and ran like a champ with no high idle.
Apparently a clean unobstructed IAC path is plenty of air at idle for an LS6 cam.
Rob (Bad30th)
Last edited by Bad30th; Mar 6, 2009 at 07:37 PM.
