Are 4150 TBs Noisy??
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
Are 4150 TBs Noisy?? I bought a used FAST 4150 throttle body a while ago and the IACV port is always so noisy. You can hear it sucking in air while cruising, it's so annoying. I put a new IACV in there to see if that would quiet it down but it does not. IACV counts are always kind of wacky. They are around ~100 when cold then eventually work their way down to zero. I'm beginning to wonder if I got a bad throttle body.
I put a piece of tape over the hole so I could tolerate driving the car in the meantime.
Are these things typically noisy or do I have a bad unit?
I put a piece of tape over the hole so I could tolerate driving the car in the meantime.
Are these things typically noisy or do I have a bad unit?
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
I closed up the blades to bring my IACV counts up. At idle in park they are over 100 but in drive they go down to zero. If I open the blades my idle gets too high. Ive checked for vacuum leaks and havent been able to find any.
I haven't used one with a stock PCM so I can't add anything helpful.
Have you adjusted your IAC steps vs effective area? I'm not 100% sure on what that actually does. Chopper Doc has a video on it, which I struggled with wrapping my head around.
That's not something I have ever messed with. Even with my NW102 T/B I left it stock and have zero problems with idle/return to idle.
Can you adjust the rear blades independently of the front?
Hopefully someone that has done tuned one of these successfully will chime in. I would like to learn how to do it.
Have you adjusted your IAC steps vs effective area? I'm not 100% sure on what that actually does. Chopper Doc has a video on it, which I struggled with wrapping my head around.
That's not something I have ever messed with. Even with my NW102 T/B I left it stock and have zero problems with idle/return to idle.
Can you adjust the rear blades independently of the front?
Hopefully someone that has done tuned one of these successfully will chime in. I would like to learn how to do it.
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
I haven't used one with a stock PCM so I can't add anything helpful.
Have you adjusted your IAC steps vs effective area? I'm not 100% sure on what that actually does. Chopper Doc has a video on it, which I struggled with wrapping my head around.
That's not something I have ever messed with. Even with my NW102 T/B I left it stock and have zero problems with idle/return to idle.
Can you adjust the rear blades independently of the front?
Hopefully someone that has done tuned one of these successfully will chime in. I would like to learn how to do it.
Have you adjusted your IAC steps vs effective area? I'm not 100% sure on what that actually does. Chopper Doc has a video on it, which I struggled with wrapping my head around.
That's not something I have ever messed with. Even with my NW102 T/B I left it stock and have zero problems with idle/return to idle.
Can you adjust the rear blades independently of the front?
Hopefully someone that has done tuned one of these successfully will chime in. I would like to learn how to do it.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo This may be a dumb question, but are you using a GM IAC? IIRC some of the aftermarket TB's use a Mopar IAC which looks very similar, I think it might even actually plug in.
You said split intake, you mean a dual plane intake?
Sniper efi systems are known to whistle on dual planes, maybe same issue as yours.
They make a “sealing plate” that gets rid of the whistle. Also read of reports that a 1/2” open spacer helps too.
Sniper efi systems are known to whistle on dual planes, maybe same issue as yours.
They make a “sealing plate” that gets rid of the whistle. Also read of reports that a 1/2” open spacer helps too.
I "think" he has the newer Holley single plane intake that is literally split down the middle and bolts together.
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
No dice with the new throttle body. Idles way high and still makes noise. It acts like it has a vacuum leak but it does not. I've checked everywhere for leaks.
I'm about to start selling stuff for a carb swap. I've had just about enough of HP tuners and efi.
I'm about to start selling stuff for a carb swap. I've had just about enough of HP tuners and efi.
11 Second Club
Joined: Jan 2003
Posts: 1,000
Likes: 134
You just need to block the IAC port with silicone and not use the IAC valve/motor at all on the 4150/4500 efi TB's. They are too difficult to tune properly and more trouble than it's worth. Set your idle with throttle blades to around 900-1000rpm and your idle will stay perfect just like a carb. IAC's are way overrated.
I sold my cathedrals super vic intake/4150tb efi setup and he uses it on a car that can be daily driven anywhere and it has a 240+ cam in it and it never stalls or behaves weird without the IAC being used. The single plane intakes smooth out the idle over the plastic ls intakes and the cars just idle better/easier so no IAC is required .........
I sold my cathedrals super vic intake/4150tb efi setup and he uses it on a car that can be daily driven anywhere and it has a 240+ cam in it and it never stalls or behaves weird without the IAC being used. The single plane intakes smooth out the idle over the plastic ls intakes and the cars just idle better/easier so no IAC is required .........
Staging Lane
Joined: May 2017
Posts: 54
Likes: 5
Your IAC counts are too high unless HP Tuners uses a different scale. I don't use HPT so I can't say...But IAC counts should be between 3 and 10ish. 100 would indicate the IAC is wide open all the time. You need to open the blades (1/4 turn at a time or less to dial it in) with the hard stop so the IAC can control the idle air. You probably need to cycle the key after each adjustment so the TPS reads "0" after each adjustment. I use the Accufab TB on a Victor Jr. with no issues. I will say with the air filter off standing near the car the air passing the IAC is a little loud but can't hear it with the AF on and certainly not while driving.
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
You just need to block the IAC port with silicone and not use the IAC valve/motor at all on the 4150/4500 efi TB's. They are too difficult to tune properly and more trouble than it's worth. Set your idle with throttle blades to around 900-1000rpm and your idle will stay perfect just like a carb. IAC's are way overrated.
I sold my cathedrals super vic intake/4150tb efi setup and he uses it on a car that can be daily driven anywhere and it has a 240+ cam in it and it never stalls or behaves weird without the IAC being used. The single plane intakes smooth out the idle over the plastic ls intakes and the cars just idle better/easier so no IAC is required .........
http:// www.youtube.com/watch?v=6rx3OnoQD-0
I sold my cathedrals super vic intake/4150tb efi setup and he uses it on a car that can be daily driven anywhere and it has a 240+ cam in it and it never stalls or behaves weird without the IAC being used. The single plane intakes smooth out the idle over the plastic ls intakes and the cars just idle better/easier so no IAC is required .........
http:// www.youtube.com/watch?v=6rx3OnoQD-0
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
You just need to block the IAC port with silicone and not use the IAC valve/motor at all on the 4150/4500 efi TB's. They are too difficult to tune properly and more trouble than it's worth. Set your idle with throttle blades to around 900-1000rpm and your idle will stay perfect just like a carb. IAC's are way overrated.
I sold my cathedrals super vic intake/4150tb efi setup and he uses it on a car that can be daily driven anywhere and it has a 240+ cam in it and it never stalls or behaves weird without the IAC being used. The single plane intakes smooth out the idle over the plastic ls intakes and the cars just idle better/easier so no IAC is required .........
http:// www.youtube.com/watch?v=6rx3OnoQD-0
I sold my cathedrals super vic intake/4150tb efi setup and he uses it on a car that can be daily driven anywhere and it has a 240+ cam in it and it never stalls or behaves weird without the IAC being used. The single plane intakes smooth out the idle over the plastic ls intakes and the cars just idle better/easier so no IAC is required .........
http:// www.youtube.com/watch?v=6rx3OnoQD-0
Thread Starter
Launching!
Joined: Mar 2012
Posts: 299
Likes: 21
From: Phoenix, AZ
I removed the IACV off my old throttle body and taped it up really good with some duct tape. It runs fine without the IACV. Actually runs better. Its much more crisp and the best part... no loud sucking noises.