Do all mono blade throttle bodies have high idle issues?

[04sleeper]

you need to datalog ISC duty cycle and ISC integrator. duty cycle should be around 35% when warmed up and integrator should as close to zero as possible. report back.

I use the Accufab mono blade.

The trick is finding a balance between the air gap of the throttle blade, and the work performed by the idle air control valve. Idle RPM is a set point. It is a closed loop process. If there are no problems with the throttle blade hanging on the case, then the combination of mechanical adjustment and electronic calibration will net the desired idle.

You can learn a lot about setting idle on an EEC-V equipped vehicle here:

spark source too low

This. It is a combination like mentioned. You MUST properly set the throttle stop, TP sensor and ISC Integrator.

If your throttle body doesn't stick when the car is shut off, then its not the throttle body.

Anyone that uses a return spring to try to fix this is only causing issues and not fixing the root of the problem.

 

[1320 Junkie]

This. It is a combination like mentioned. You MUST properly set the throttle stop, TP sensor and ISC Integrator.

If your throttle body doesn't stick when the car is shut off, then its not the throttle body.

Anyone that uses a return spring to try to fix this is only causing issues and not fixing the root of the problem.

How do you figure the return spring is causing issues? How do you know whipples vendor doesn't use a shitty spring with not enough tension on it to keep the blade closed at idle,there needs to be a certain amount of tension on the blade so the iac can do its job,period. Ever feel the difference between throttle bodies pedal feel, I have and the only one ever to be perfect was a dragon and stock, all others felt too light. my pedal feels perfect and the car drives,idles as if it were stock I set my car up myself and dialed everything in perfectly , still idled high like he's expieriencing....the putty is doing the same thing the return spring would do, close the air gap around the blade.

 

[04sleeper]

How do you figure the return spring is causing issues? How do you know whipples vendor doesn't use a shitty spring with not enough tension on it to keep the blade closed at idle,there needs to be a certain amount of tension on the blade so the iac can do its job,period. Ever feel the difference between throttle bodies pedal feel, I have and the only one ever to be perfect was a dragon and stock, all others felt too light. my pedal feels perfect and the car drives,idles as if it were stock I set my car up myself and dialed everything in perfectly , still idled high like he's expieriencing....the putty is doing the same thing the return spring would do, close the air gap around the blade.

Yes. I have installed and adjusted Whipple, Accufab, Billetflow, Dragon, LFP and stock Throttle bodies. I am very familiar with all of them.

I also do all my installs as well as all my own tuning so I know exactly how each part works and is supposed to work.

 

[1320 Junkie]

Yes. I have installed and adjusted Whipple, Accufab, Billetflow, Dragon, LFP and stock Throttle bodies. I am very familiar with all of them.

I also do all my installs as well as all my own tuning so I know exactly how each part works and is supposed to work.

Wasn't my question.....how do u know the blade isn't being held open by the air being sucked in by the blower rendering the tbs spring insufficient...all the electrical adjustments in the world don't account for inadequate mechanical parts. The amount of air getting by could be a milimeters worth and still jam the idle up a few hundred rpm.

 

[MalcolmV8]

This. It is a combination like mentioned. You MUST properly set the throttle stop, TP sensor and ISC Integrator.

If your throttle body doesn't stick when the car is shut off, then its not the throttle body.

You're the second person to mention ISC Integrator. What is that?

You list just about every brand of throttle body and say you've worked with all of them. How common is it to have the mono blades not seal right?

When I putty the blade and seal the excess air escaping by the blade and it fixes everything, yet you don't think that's the issue. Can you tell me how I get around this then? What's the fix to compensate for the leaking air? As stated above several times my IAC can be completely off (unplugged) and the car is still idling around 1100 ~ 1200 rpms.

You say if my throttle body doesn't stick when the car is shut off then it's not the issue? I'm not following that logic, can you explain?

Thanks

 

[eodtech72]

As I posted earlier I had problems similar with my Dragon TB. Mine felt fine with the car not running but when running at idle the blade would get sucked open and not be resting on the stop like it did while not running. Mine had to have the blade adjusted (by Dragon)and worked perfectly afterwards.

You should try unplugging the IAC, start the car and adjust the stop screw to see if you can get the idle to just below whatever you idle is set to in your tune. If you can get it to lower with the stop screw and it's still in contact when closed turn the car off plug the IAC back in and reflash you tune to erase adaptive memory. Then start the car without touching the gas at all and let it idle for 10 mins or so until it's at normal temp.

A return spring should not be needed if the TB has the correct geometry when it's made. Hope this helps.

 

[Co-brat]

Man I cant really add anything to this thread cause im here to learn about stuff like this but heres what I do know.... 04Sleeper seems to have a very sick obsession with throttle bodies lol as I have seen him comment in every single throttle body thread ive ever read and I would take his advice pretty serious. I think he has this shit down, you tell em Kevin!

 

[03Cobrra]

I'm having the exact same idle issues as you. Havent had any time to try and fix it yet though. Please keep us updated if you figure it out.

 

[SLPRCTM]

The problem is caused by the air passing by the blade holding it slightly open. Try this to prove it. Start the car and bring the rpm's up to about 2k. Then slowly let off the throttle as to let the idle get"stuck". While watching the gap closely between the throttle arm and throttle stop screw, have someone else turn off the ignition. As soon as the engine starts to shut down and the vacuum from the engine decreases, you will see the throttle arm sit back on the adjustment screw. The only thing I found with my billetflow was to have the gap on the bottom slightly larger than the top. It is the air rushing by the top of the blade that is holding it open. After you figure out the sweet spot, then have the car re-learn the idle.

 

[MalcolmV8]

You should try unplugging the IAC, start the car and adjust the stop screw to see if you can get the idle to just below whatever you idle is set to in your tune.

I have tried that many times. The lowest idle you can get with the IAC unplugged (or plugged in) is around 1200 rpms no matter how far out you turn that set screw.

I'm having the exact same idle issues as you. Havent had any time to try and fix it yet though. Please keep us updated if you figure it out.

Will do.

The problem is caused by the air passing by the blade holding it slightly open. Try this to prove it. Start the car and bring the rpm's up to about 2k. Then slowly let off the throttle as to let the idle get"stuck". While watching the gap closely between the throttle arm and throttle stop screw, have someone else turn off the ignition. As soon as the engine starts to shut down and the vacuum from the engine decreases, you will see the throttle arm sit back on the adjustment screw. The only thing I found with my billetflow was to have the gap on the bottom slightly larger than the top. It is the air rushing by the top of the blade that is holding it open. After you figure out the sweet spot, then have the car re-learn the idle.

Perhaps the billetflow and whipple throttle bodies are different but I can't adjust the gap at the top and bottom independently. There's only one set screw.
As mentioned above there is no spot where the engine starts to shutdown or vacuum decrease. No matter how "closed" you get the throttle body it's still idling around 1200 rpms unless I seal the TB with some putty as shown in the pic earlier in the thread.

 

[SLPRCTM]

I think I might not have explained it right. To adjust the blade it's self, you loosen the screws holding the actual blade to the shaft and let the throttle snap closed a few times. Then tighten the screws. The shut down and decrease in vacuum is what I meant when you turn off the key and the motor stops running. While the engine is running at idle, the vacuum from the motor is holding the blade slightly open. When you turn off the engine, you can watch it move back onto the idle stop screw.

 

[1320 Junkie]

^^^ I've done the above with a bbk twin blade...loosen screws and let the blade center itself in the bore ,re tighten screws after you snap it shut a few times letting the spring slam it shut.

 

[encasedmetal]

OP- sorry I am late to answer your question
ISC duty cycle: this value tells you how much the IAC valve is having to stay open in order to control idle. ideally you want to be around 35%.
Idle air integrator- this is a value that correlates with the idle air neutral table values in your tune. They should be fairly close to zero. If it’s negative then you need to take air out of the ISC tables, if it’s positive then you need to add air into the tables. It’ll never be exactly zero. Allow the car to be at operating temp and idling for a few minutes before making a decision on this. In layman's terms- the integrator could be telling your ecu that more air is coming in than what is actually coming in- causing your high idle. even if your TB and your IAC valve are working properly this can cause high idle.
TPS- this needs to be inbetween 0.95-1.0 v or 15-20% whichever way your scanner reads as SCT xcal won't read this.

 

[encasedmetal]

also- are you using livelink or just your xcal? try to use livelink v6.5 and log spark source (should be at 9 if idle is being controlled)

 

[04sleeper]

Wasn't my question.....how do u know the blade isn't being held open by the air being sucked in by the blower rendering the tbs spring insufficient...all the electrical adjustments in the world don't account for inadequate mechanical parts. The amount of air getting by could be a milimeters worth and still jam the idle up a few hundred rpm.

There is not one aftermarket single blade throttle body out there that will close and seal exactly like the factory twin bore throttle body. The factory twin bore throttle body has round blades and the singles have oval. By nature the single will never seal the same way a twin bore will.

Hold a stock throttle body up to the light and see how much light shines through around the blades. Now do the same with the aftermarket. You will see what I am talking about.

The IAC valve controls the amount of air bypassing the throttle body so the car can idle. Since the stock throttle body seals very well, the IAC valve needs to flow a certain amount of air to keep the idle correct. If you leave the tune set with the factory values, the IAC valve assumes you have the stock throttle body that seals perfectly. Remember the aftermarket single blade by nature will never seal the same and air will get around the blade and housing causing a high idle. The ECU is doing EXACTLY as it is commanded to do causing the high idle. Adding an extra spring only fights what the IAC valve is trying to control. Byadding the extra spring you only mask the problem, you do not fix it!

If you do not properly set the set screw, set the TP sensor, and Idle air integrator in the tune, you will never have it correct.

You're the second person to mention ISC Integrator. What is that?

See encasedmetal's post explaining it. He is spot on!

You list just about every brand of throttle body and say you've worked with all of them. How common is it to have the mono blades not seal right?

Every single one of them.

When I putty the blade and seal the excess air escaping by the blade and it fixes everything, yet you don't think that's the issue. Can you tell me how I get around this then? What's the fix to compensate for the leaking air? As stated above several times my IAC can be completely off (unplugged) and the car is still idling around 1100 ~ 1200 rpms.

Follow the steps below and you will have it working.
Ok, first, the lever MUST rest on the stop screw. Otherwise the throttle position is never the same and the computer don't know what to do , so it idles high.

1. Warm up car
2. Turn engine off and REMOVE THE KEY
3. Disconnect negative lead from battery and turn head lights on( this removes the capacitive charge in the system)
4. Connect negative lead to battery
5. Back off the stop screw on the throttle body
6. Start car
7.While grasping the throttle lever with your hand, give it a small amount of throttle and let off SLOWLY.
8. Adjust the stop screw to just meet the lever and give it another 1/8-1/4 turn and, then lock it down.
9. Turn ignition off.
10. Turn key to "ON" position and check TPS voltage. Set to .980 Volts with a Digital Multimeter (Fluke Meters are the most accurate)
11. Turn key off.
12. Repeat steps 1-4 to reset ECU.
13. Turn off Adaptive Learning in your tune so you can make the proper adjustments without the ECU making them for you. (Your tuner should know how to do this)
14. Datalog ISC duty cycle: this value tells you how much the IAC valve is having to stay open in order to control idle. ideally you want to be around 35%.
15. Datalog Idle air integrator- this is a value that correlates with the idle air neutral table values in your tune. They should be fairly close to zero. If it’s negative then you need to take air out of the ISC tables, if it’s positive then you need to add air into the tables. It’ll never be exactly zero. Allow the car to be at operating temp and idling for a few minutes before making a decision on this. In layman's terms- the integrator could be telling your ecu that more air is coming in than what is actually coming in- causing your high idle.
16. Turn on Adaptive Learning in your tune and drive car as you normally would so that the ECU can relearn again.

You say if my throttle body doesn't stick when the car is shut off then it's not the issue? I'm not following that logic, can you explain?

Thanks

With the car off, take your hand and manually open and close the throttle body. If it does not "Stick" or and comes to rest on the throttle stop, it is working properly.

OP- sorry I am late to answer your question
ISC duty cycle: this value tells you how much the IAC valve is having to stay open in order to control idle. ideally you want to be around 35%.
Idle air integrator- this is a value that correlates with the idle air neutral table values in your tune. They should be fairly close to zero. If it’s negative then you need to take air out of the ISC tables, if it’s positive then you need to add air into the tables. It’ll never be exactly zero. Allow the car to be at operating temp and idling for a few minutes before making a decision on this. In layman's terms- the integrator could be telling your ecu that more air is coming in than what is actually coming in- causing your high idle. even if your TB and your IAC valve are working properly this can cause high idle.
TPS- this needs to be inbetween 0.95-1.0 v or 15-20% whichever way your scanner reads as SCT xcal won't read this.

This is spot on! Thank you.

I would also like to add that due to the nature of single blade throttle bodies being oval, the cam eccentric needs a different profile than stock to make the car respond the same. Most do not have the proper cam eccentric geometry. Accufab, for example has a cam eccentric from a 2000 Cobra R. Which causes the cruise control to "Hessitate" when engaging.

Also, this is why most people "Feel" like the single blade throttle body gives them more "Throttle Response" It's all relative to the cam eccentric.

Given the same amount of flow, a twin bore throttle body will make the same amount of power as the single blade yet it will provide a much more stable foundation due to the shaft having a support in the middle between the blades as opposed to the single having no support in the middle.

On High HP applications a single blade can actually "Bend" upon closing. This is one of the resaons you see OEM's choose large twin bore throttle bodies over single. "A La Ford GT", "GT 500", etc....

Hope this helps.

 

[Ironhand]

I wonder if you should flip your IAC upside down...? My car had no problems idling at 800rpm with a good tuner.

 

[MalcolmV8]

There is not one aftermarket single blade throttle body out there that will close and seal exactly like the factory twin bore throttle body. The factory twin bore throttle body has round blades and the singles have oval. By nature the single will never seal the same way a twin bore will.

Hold a stock throttle body up to the light and see how much light shines through around the blades. Now do the same with the aftermarket. You will see what I am talking about.

The IAC valve controls the amount of air bypassing the throttle body so the car can idle. Since the stock throttle body seals very well, the IAC valve needs to flow a certain amount of air to keep the idle correct. If you leave the tune set with the factory values, the IAC valve assumes you have the stock throttle body that seals perfectly. Remember the aftermarket single blade by nature will never seal the same and air will get around the blade and housing causing a high idle. The ECU is doing EXACTLY as it is commanded to do causing the high idle. Adding an extra spring only fights what the IAC valve is trying to control. Byadding the extra spring you only mask the problem, you do not fix it!

If you do not properly set the set screw, set the TP sensor, and Idle air integrator in the tune, you will never have it correct.


See encasedmetal's post explaining it. He is spot on!


Every single one of them.


Follow the steps below and you will have it working.
Ok, first, the lever MUST rest on the stop screw. Otherwise the throttle position is never the same and the computer don't know what to do , so it idles high.




With the car off, take your hand and manually open and close the throttle body. If it does not "Stick" or and comes to rest on the throttle stop, it is working properly.


This is spot on! Thank you.

I would also like to add that due to the nature of single blade throttle bodies being oval, the cam eccentric needs a different profile than stock to make the car respond the same. Most do not have the proper cam eccentric geometry. Accufab, for example has a cam eccentric from a 2000 Cobra R. Which causes the cruise control to "Hessitate" when engaging.

Also, this is why most people "Feel" like the single blade throttle body gives them more "Throttle Response" It's all relative to the cam eccentric.

Given the same amount of flow, a twin bore throttle body will make the same amount of power as the single blade yet it will provide a much more stable foundation due to the shaft having a support in the middle between the blades as opposed to the single having no support in the middle.

On High HP applications a single blade can actually "Bend" upon closing. This is one of the resaons you see OEM's choose large twin bore throttle bodies over single. "A La Ford GT", "GT 500", etc....

Hope this helps.

Kevin, that helps a lot. Thank you. What I'm understanding from your information is that the air escaping around the TB blade an be compensated for. If I'm understanding the procedure you explained above it's my "idle air integrator" that's off. I know it's not my IAC (at least not yet) because I can completely unplug it and the car is still idling high.

The car basically thinks there's more air or less air than what's really coming in and it's causing a high idle (idle air integrator table been off). I assume the high idle is been caused by timing changes by the ECC? By advancing or retarding the timing it can bring the idle up or down?

When my replacement SCT hand held arrives tomorrow I'll get it hooked up to my laptop with live link and report back what idle air integrator tables are.
I'm surprised my tuner didn't bring this up.

I wonder if you should flip your IAC upside down...? My car had no problems idling at 800rpm with a good tuner.

From what I understand the the IAC is directional. I'm told if you flip them upside down you can experience a surging idle. So far my problem is beyond the IAC. I need to get my car to idle down to where the IAC can even control the idle.

 

[1320 Junkie]

04 sleeper- like I said its a mechanical issue, a flawed design in the tb's. I agree the issue can be fixed with all kinds of tweaking in the tune but the springs they put in these aftermarket tb's are still too weak.....there's more than one issue going on once these shitty tb's are installed....and they can drive u crazy if u don't know what you doing. I have my dyno tune tomorrow with my own 2.9 crusher setup...numbers and vid to follow.

 

[04sleeper]

04 sleeper- like I said its a mechanical issue, a flawed design in the tb's. I agree the issue can be fixed with all kinds of tweaking in the tune but the springs they put in these aftermarket tb's are still too weak.....there's more than one issue going on once these shitty tb's are installed....and they can drive u crazy if u don't know what you doing. I have my dyno tune tomorrow with my own 2.9 crusher setup...numbers and vid to follow.

I agree, the design is less than desirable and this is why they are not as easy as a "Bolt On" item and why you hear so many issues with them.

But there "Is" a way to make them work properly and not have a 100 lb pedal while doing it.

 

[04sleeper]

Kevin, that helps a lot. Thank you. What I'm understanding from your information is that the air escaping around the TB blade an be compensated for. If I'm understanding the procedure you explained above it's my "idle air integrator" that's off. I know it's not my IAC (at least not yet) because I can completely unplug it and the car is still idling high.

The car basically thinks there's more air or less air than what's really coming in and it's causing a high idle (idle air integrator table been off). I assume the high idle is been caused by timing changes by the ECC? By advancing or retarding the timing it can bring the idle up or down?

You can choose to "Lock" the timing in the "Desired Idle Spark Neutral" table via ECT if you so desire, but you can set the Idle in the Idle Scalars. You can also datalog Desired Idle Speed and Actual Idle speed to see if what's commanded is working properly.

When my replacement SCT hand held arrives tomorrow I'll get it hooked up to my laptop with live link and report back what idle air integrator tables are.
I'm surprised my tuner didn't bring this up.

I'm actually not surprised. I don't see many people tuning properly these days.