?'s on Drill Mod on PP TB
I've had several come in my shop with no cold start fast idle, stalls in gear with the AC on, or just stalls when put in gear. Cleaning around the throttle blades usually fixed them. The IAC can not bypass enough idle air alone. Part of a decent normal tune up is cleaning the throttle body. Brings the IAC counts right back down.
If you had enough every day experience doing this you would not be saying that. You simply are mistaken.
If you actually worked in a shop you would also see many throttle blades with factory holes in them. Just because you don't see them in an LT1.....
Last edited by Ed Wright; Dec 30, 2013 at 12:28 PM.
Why did GM do it this way, Ed? Why didn't they just crack the blades? Think of all the drill bit money they would have saved!!!!! I usually read your posts and learn something but you are wrong here. Oh, when did I say I was an expert? I barely know how to change my oil. I'm sure you could tell me how I'm doing that wrong as well.
Just curious, I'm way out of my league here though, but do you check vacuum before and after playing with the throttle blades? Also, do you do much with afr balance bank to bank? You know, the whole split blm's thing everyone seems to chase or is that a lost cause/unnecessary repair?
Why did GM do it this way, Ed? Why didn't they just crack the blades? Think of all the drill bit money they would have saved!!!!! I usually read your posts and learn something but you are wrong here. Oh, when did I say I was an expert? I barely know how to change my oil. I'm sure you could tell me how I'm doing that wrong as well.
Edit: You aren't going to encounter this on a car where everything is kept clean. Only a bone stock daily driver, like a Caprice, something just driven a lot of miles.
Last edited by Ed Wright; Dec 31, 2013 at 12:59 PM.
Read what I said again. They did crack the throttle blades. If they didn't, gunk around the throttle blades would not cause idle problems, right? If they were shut tight the IAC could handle it all. If you did as much actual work with these as I, you would have encountered it yourself.
Edit: You aren't going to encounter this on a car where everything is kept clean. Only a bone stock daily driver, like a Caprice, something just driven a lot of miles.
Edit: You aren't going to encounter this on a car where everything is kept clean. Only a bone stock daily driver, like a Caprice, something just driven a lot of miles.
Yes, the Taurus, and a couple other Fords, had that sticker.
If the IAC had enough capacity alone, dirty throttle bores would not cause start up and stalling issues. It would be able to compensate. Maxed out IAC counts and still can't idle well. Clean the crap around the throttle blades and they come right down and the stalling ends.
I have yet to see a fuel balance issue worsen from cracking the throttle blades open, but you HAVE to maintain zero throttle angle. If it is a very radical cam or stroker engine the stock TBs often need the hole between the throttle bores drilled a little larger. As I mentioned, I have yet had to do any drilling with a 58mm. Throttle blades that big don't require much movement to allow enough air for the IAC to be able to handle it.
That milled out area between the throttle bores is a dumb deal, and often requires individual cylinder fueling adjustments. Modified engines often do anyway.
If the IAC had enough capacity alone, dirty throttle bores would not cause start up and stalling issues. It would be able to compensate. Maxed out IAC counts and still can't idle well. Clean the crap around the throttle blades and they come right down and the stalling ends.
I have yet to see a fuel balance issue worsen from cracking the throttle blades open, but you HAVE to maintain zero throttle angle. If it is a very radical cam or stroker engine the stock TBs often need the hole between the throttle bores drilled a little larger. As I mentioned, I have yet had to do any drilling with a 58mm. Throttle blades that big don't require much movement to allow enough air for the IAC to be able to handle it.
That milled out area between the throttle bores is a dumb deal, and often requires individual cylinder fueling adjustments. Modified engines often do anyway.
And, I'm guessing you really think drive-by-wire cars are really a screwed deal.
You do know they have no IAC. Right?
Idle is controlled by opening and closing of the throttle blade. LOL
Many LS cars & trucks also came with a hole in the throttle blade.
You do know they have no IAC. Right?
Idle is controlled by opening and closing of the throttle blade. LOL
Many LS cars & trucks also came with a hole in the throttle blade.
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The LS intake is very different and can front feed the cylinders much more evenly than the ultra short LT1 runners. If you try and idle an LT1 just through the front not through the IAC distribution the fronts run lean and the back rich. You can find threads about guys going to pretty great lengths to resolve this on monoblade street cars.
Same with my LPE/Accel billet TB. Probably made at the same place. For years I coudln't figure out why the car would idle like crap for the first week of driving whenever the PCM was reset. Never paid attention to the drill mod until recently.
I don't need to go find any "threads", if you have the slightest clue what your doing it takes a couple of key strokes to fix that. GM did that from the factory with the stock manifold's IAC passage.
Unlike many of you, I've had several hooked up with eight wide bands, and know how to correct that, if it shows up. With ported heads and ported intakes, they aren't all lean at 1 & 2. Modified engines shuffle all that around.
Unlike many of you, I've had several hooked up with eight wide bands, and know how to correct that, if it shows up. With ported heads and ported intakes, they aren't all lean at 1 & 2. Modified engines shuffle all that around.
I don't need to go find any "threads", if you have the slightest clue what your doing it takes a couple of key strokes to fix that. GM did that from the factory with the stock manifold's IAC passage.
Unlike many of you, I've had several hooked up with eight wide bands, and know how to correct that, if it shows up. With ported heads and ported intakes, they aren't all lean at 1 & 2. Modified engines shuffle all that around.
Unlike many of you, I've had several hooked up with eight wide bands, and know how to correct that, if it shows up. With ported heads and ported intakes, they aren't all lean at 1 & 2. Modified engines shuffle all that around.
I didn't realize lt1's were drive by wire, Ed. My mistake, you are always correct and have done everything twice and better than everyone else. Can't teach an old dog new tricks.....too stubborn to realize they are wrong.
Difference between you and I is that I learned by doing it, you read about it on internet message boards. How many have you had on a dyno with eight wide bands to actually see the variation in air/fuel? I'm guessing real close to zero.
Many guys I race use Racepack data loggers, and run eight wide bands all the time. We don't have to stagger jet EFI, we correct cylinder-to-cylinder air/fuel variations with the key board. Stock eliminator cars I help use stock throttle bodies and intake manifolds. My Hogan intake has no IAC passeges. Never a problem correcting it.
sounds like a few guys here are arguing just to argue lol......ed's absolutely correct with everything hes said, the ls cars run absolutely perfect with the ETC even with monster cams, ive done plenty of them they work fine..gm leaves ALL throttle blades open a bit, the new ETC pcms depend on this, they calculate airflow based off of the effective idle area at closed throttle (the half moon shaped slit that is open at the bottom of the throttle)..why would gm base ALL of their idle calculations on their newer stuff off this if it didn't work?????.....as for the lt stuff I always suggest a tb with an idle screw, you crack it open that way, I HATE drilling holes for no reason....I too have had 8 wb02's on mine with the stock and my single plane, I can tell you most of the balance issues are due to the cam design and reversion in the intake rather than the intake, I know someone with the same single plane setup I have on a sbc, with 8 wb's he was off almost a full point plus in some spots, mine on the other hand was off no more than .2 afr across the board
wow dick swinging contest huh?? Im surprised to see all the dumbass comments about other cars lol. If cracking the throttle blades was what GM was doing, then why did they even spend a ton of time/money putting the idle air passages under the intake?? Can drilling the hole a bit larger correct high idle counts? Sure it can. Is it the easiest? No. Is it the only way? No. Does cracking the blades a bit more do the same thing? No but Yes. Does the difference require me to show how big my dick is to show that other less experienced members are doing it the hard way? No.
Dick swingers and worse that Nut Huggers.... F the internet threads.
Dick swingers and worse that Nut Huggers.... F the internet threads.