Do all mono blade throttle bodies have high idle issues?

[MalcolmV8]

I've been struggling with a high idle issue ever since installing my 2.9 Whipple Crusher with whipple's mono blade TB.

You can see some details towards the end of this thread

http://www.svtperformance.com/forum...5-those-have-installed-whipple-crusher-6.html

In summary I'm on my third TB from them. My car would idle around 1600 RPMs and when removing the TB and holding it up to the light you could see light shining past the TB blade where air would be escaping past.
Force the TB closed with your hand really hard and idle would come right down.

They replaced the TB and it was slightly better but still not good. Still see light shinning past. The third TB they sent me you can see they've done a lot of smoothing of the blade to try and make it seal better. They said they smoothed it with a lapping compound. While it's the best yet it's still not good. Car idles around 1100 to 1200 or so still. I can get it down to 1000 RPMs if I put on two massive throttle return springs and I adjust my TPS way lower than it should be. 0.89 volts instead of 0.98 as measured key on/engine off.

Is this a common issue with mono blade throttle bodies? Do other people have these issues? Could my tune be causing this?

I'm sure someone is going to throw out vacuum leaks and if you do please be more specific or have something in mind. I've double, triple, and quadruple checked for vacuum leaks. I've also packed kids play dough (like putty) around the perimeter of the TB blade to block the air and then started the car and it idled perfect. If I disconnected the IAC at that point the motor would die as expected.
Remove the putty and the car idles so high from air escaping by the TB I can unplug the IAC and the idle is not phased at all. However force the TB closed really hard by hand and idle will go all the way down.

Ideas please.

Thanks
Malcolm

 

[keith89]

I've been struggling with a high idle issue ever since installing my 2.9 Whipple Crusher with whipple's mono blade TB.

You can see some details towards the end of this thread

http://www.svtperformance.com/forum...5-those-have-installed-whipple-crusher-6.html

In summary I'm on my third TB from them. My car would idle around 1600 RPMs and when removing the TB and holding it up to the light you could see light shining past the TB blade where air would be escaping past.
Force the TB closed with your hand really hard and idle would come right down.

They replaced the TB and it was slightly better but still not good. Still see light shinning past. The third TB they sent me you can see they've done a lot of smoothing of the blade to try and make it seal better. They said they smoothed it with a lapping compound. While it's the best yet it's still not good. Car idles around 1100 to 1200 or so still. I can get it down to 1000 RPMs if I put on two massive throttle return springs and I adjust my TPS way lower than it should be. 0.89 volts instead of 0.98 as measured key on/engine off.

Is this a common issue with mono blade throttle bodies? Do other people have these issues? Could my tune be causing this?

I'm sure someone is going to throw out vacuum leaks and if you do please be more specific or have something in mind. I've double, triple, and quadruple checked for vacuum leaks. I've also packed kids play dough (like putty) around the perimeter of the TB blade to block the air and then started the car and it idled perfect. If I disconnected the IAC at that point the motor would die as expected.
Remove the putty and the car idles so high from air escaping by the TB I can unplug the IAC and the idle is not phased at all. However force the TB closed really hard by hand and idle will go all the way down.

Ideas please.

Thanks
Malcolm

Any throttle body will have a high idle if the throttle stop is not adjusted properly. Try screwing in or out the throttle stop to different positions to see if it changes. You may need to reset the computer after each change by unplugging the battery to reset the iac otherwise it may take a few minutes to relearn idle.

 

[Carbd86GT]

It's most likely the tune. The blade isn't supposed to be shut all the way, there will always be a very little air gap. If you can just barely see light past the blade, then it's fine, that's normal. The IAC is what controls the idle, not the throttle body, it is most likely open too much causing the high idle.

 

[Tims97SVT]

It's most likely the tune. The blade isn't supposed to be shut all the way, there will always be a very little air gap. If you can just barely see light past the blade, then it's fine, that's normal. The IAC is what controls the idle, not the throttle body, it is most likely open too much causing the high idle.

Agreed.

Remove tps.
Adjust base idle with the throttle stop screw.
Reinstall tps and adjust voltage to .98 with key on engine off.
Start the car and let it idle. Run it around some and see what it does. You may have to adjust idle rpm in your tuner.

 

[eodtech72]

I had similar issues with my dragon TB. Had to use a return spring to get it to close once the car was running and it also was sticking some. After lots of troubleshooting I did figure out some good info to know: the base idle should be set with the IAC unplugged and it has to be lower than the idle speed set in your tune. If its higher because of an issue with your TB the IAC will not be able to control the idle correctly.
My issues were fixed by sending my Dragon TB in to have it adjusted. When I got it back and installed it the idle was perfect. Sounds like you need that TB replaced or adjusted correctly by the manufacturer.
Hopefully you get it figured out.

 

[MalcolmV8]

Any throttle body will have a high idle if the throttle stop is not adjusted properly. Try screwing in or out the throttle stop to different positions to see if it changes. You may need to reset the computer after each change by unplugging the battery to reset the iac otherwise it may take a few minutes to relearn idle.

I forgot to mention throttle stop screw in my original post. Yes it's turned all the way out which I might add does cause the TB blade to stick in the closed position but that's a whole different issue.

It's most likely the tune. The blade isn't supposed to be shut all the way, there will always be a very little air gap. If you can just barely see light past the blade, then it's fine, that's normal. The IAC is what controls the idle, not the throttle body, it is most likely open too much causing the high idle.

I agree but when so much air is passing the throttle body blade that I can unplug my IAC effectively shutting it down and my idle is still 1100 rpms. This means my IAC is unable to control the idle.

Agreed.

Remove tps.
Adjust base idle with the throttle stop screw.
Reinstall tps and adjust voltage to .98 with key on engine off.
Start the car and let it idle. Run it around some and see what it does. You may have to adjust idle rpm in your tuner.

Throttle screw stop is backed all the way out and tune has idle set at 850 rpms.

I had similar issues with my dragon TB. Had to use a return spring to get it to close once the car was running and it also was sticking some. After lots of troubleshooting I did figure out some good info to know: the base idle should be set with the IAC unplugged and it has to be lower than the idle speed set in your tune. If its higher because of an issue with your TB the IAC will not be able to control the idle correctly.
My issues were fixed by sending my Dragon TB in to have it adjusted. When I got it back and installed it the idle was perfect. Sounds like you need that TB replaced or adjusted correctly by the manufacturer.
Hopefully you get it figured out.

Yup my issue exact. I can't get base idle low enough so that IAC can control it. I have indeed sent it back to whipple twice. This is my third throttle body.

 

[Carbd86GT]

I forgot to mention throttle stop screw in my original post. Yes it's turned all the way out which I might add does cause the TB blade to stick in the closed position but that's a whole different issue.

^ This is why it's not supposed to close all the way. If anything, there should be a little hole on the blade itself, plug it and see if it changes.

We've sent out quite a few of these throttle bodies and haven't had a single issue reported to us, 0. It's essentially the same unit as the GT500 throttle body as well, so there's another several hundred of those out there.

If plugging the hole in the blade doesn't change anything, it's more than likely the tune.

 

[cobracide]

I slotted the tps, rotated it, reset the pcm. You should get an idle below 1k. Setting the base idle first is a good idea. You will need about a 1/4 or more engagement with the throttle blade screw.

 

[MalcolmV8]

^ This is why it's not supposed to close all the way. If anything, there should be a little hole on the blade itself, plug it and see if it changes.

We've sent out quite a few of these throttle bodies and haven't had a single issue reported to us, 0. It's essentially the same unit as the GT500 throttle body as well, so there's another several hundred of those out there.

If plugging the hole in the blade doesn't change anything, it's more than likely the tune.

On my third TB I have not changed the set screw. Whipple pre-set it for me and put a sticky note on it saying "Don't adjust the screw".
I don't see a hole in the blade anywhere. If I hold it up to the light there's no holes or air spaces except for the small amount of light around the top/bottom of the TB.

I slotted the tps, rotated it, reset the pcm. You should get an idle below 1k. Setting the base idle first is a good idea. You will need about a 1/4 or more engagement with the throttle blade screw.

Yes my TPS is slotted so I can adjust it. I will unplug the battery and reset the PCM tonight but I have tried that on the prior two TBs they sent me.
I can't get a base idle below 1100 rpms even with IAC unplugged.

 

[Tims97SVT]

Sounds like its something other then the tb.

 

[encasedmetal]

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.

 

[Carbd86GT]

sounds like its something other then the tb.

+1

 

[MalcolmV8]

Sounds like its something other then the tb.

I didn't get a chance to do the putty test on this third TB last night as we had heavy thunderstorms roll thought and I was forced to stop testing and close up the garage but tonight I will try.

However on the prior TBs I put some putty around the closed TB blade to seal air leaking by and it immediately cured the problem. To me that seems definitive that the problem is the TB.

 

[MalcolmV8]

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.

Can you explain what those are? I'm not familiar with ISC. I know what a duty cycle is but what's "integrator"?
I can do those tests on Friday. My replacement SCT X3 handheld arrives on Friday.

 

[1320 Junkie]

Unplug iac, start car (if u can, if not adjust idle screw). Set rpm via screw. Turn car off, set tps to 1v or 2.0 counts in sct. Plug in iac again , disconnect ground...discharge electrical system by turning on head lights with battery disconnected. Reconnect battery, start the car and don't touch the gas, let it settle itself. If that doesn't work either ur iac is bad or u have a leak somewhere else assuming your tb is working properly...with or without a return spring.

 

[MalcolmV8]

Unplug iac, start car (if u can, if not adjust idle screw). Set rpm via screw. Turn car off, set tps to 1v or 2.0 counts in sct. Plug in iac again , disconnect ground...discharge electrical system by turning on head lights with battery disconnected. Reconnect battery, start the car and don't touch the gas, let it settle itself. If that doesn't work either ur iac is bad or u have a leak somewhere else assuming your tb is working properly...with or without a return spring.

Your first step
"Unplug iac, start car (if u can, if not adjust idle screw). Set rpm via screw."

My car fires right up and idles at 1100 ~ 1200 ish rpm in that state. yes IAC unplugged. Even with set screw on TB turned back all the way to where the blade is jamming in the housing.

 

[cobracide]

Push your throttle volts LOW by rotating the TPS and see what happens. Once it goes below 1k, leave it there for a while to get your PCM to get used to it. Had mine in the .8x volts range for a short time. After a week or few days, you can push it back up to where it needs to be.. ie. .95v

At least that's what worked for me, along with setting the base idle, throttle blade screw ~1/2 turn engagement.

 

[1 Alibi 2]

Whipple doesn't recommend their mono-blades for street use.....tuning & driveability issues !!
After having ( 3 ) of them & still having issues, see if you can get a refund. with the refund buy this.....................problem solved..
.
FRPP part # ( M-9926-SCJ ).....Mfg. by Accufab
Installed on my 2.9 w/ crusher inlet.
No tuning issues, good for cruising, good for stop & go, just as smooth as the twin 65 mm it replaced !!
.
.

.

 

[03Steve]

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

 

[MalcolmV8]

OK guys. Here's my tests tonight.

Car fully warmed first.

Battery cable pulled for 15 min.
Fire up car and it idles at 1500 ~ 1600 rpms.
Unplug IAC and it drops to around 1100 ~ 1200 rpms (or just leave car idling for a long time and ECC learns to close IAC and idle comes down to a best of 1100 ~ 1200 rpms due to air passing in TB.

Battery cable pulled for 15 min.
Seal throttle body blade this time like this with some putty

Fire up car and it idles perfect at 800 ~ 850 rpms.
Pull IAC and the motor dies immediately (very good, tells me IAC was controlling idle).

I don't see how that can be ANYTHING but the throttle body. I guess I will call Whipple in the morning for my 4th throttle body.

Assuming worse case and they can't fix this is there an alternative brand that does work that's the same size that will fit on the 2.9 crusher?

Thanks
Malcolm