Kennebell throttle Body issues

[EvilSnake]

I gave KB a call and eventually got on the line with one of their engineers. He had me do a few things and send some pics. In his estimation the TB seemed fine, but he said I could send it in and have it refreshed/repaired for $200. So that's an option for you if greasing it doesn't work.

I’m going to ride this out to see if I can find a fix for it. It seems the more I drive the car - the less it occurs. It’s very interesting that there’s a few of us having this exact problem right now. That leads me to believe that it’s something very simple causing the problem.

 

[RBB]

I’m going to ride this out to see if I can find a fix for it. It seems the more I drive the car - the less it occurs. It’s very interesting that there’s a few of us having this exact problem right now. That leads me to believe that it’s something very simple causing the problem.

Interesting....the more I drove mine the more it occurred. On the initial startup, I went on about a 15 minute cruise and everything was fine. Fired it up a few days later to do the idle/cruise logs for Lund and as soon as it got warm it failsafed. Did the same thing after greasing it as well, only a few minutes before nonstop failsafe.

 

[EvilSnake]

Interesting....the more I drove mine the more it occurred. On the initial startup, I went on about a 15 minute cruise and everything was fine. Fired it up a few days later to do the idle/cruise logs for Lund and as soon as it got warm it failsafed. Did the same thing after greasing it as well, only a few minutes before nonstop failsafe.

I should note that I’ve driven mine A LOT since this started, in a effort to figure out what is actually happening. At one point (in the beginning) I couldn’t make 1 mile without having to restart the car 3 times. But it’s spaced out a lot since then. The other night I did a 1 hour cruise and it only occurred once.

 

[RBB]

I should note that I’ve driven mine A LOT since this started, in a effort to figure out what is actually happening. At one point (in the beginning) I couldn’t make 1 mile without having to restart the car 3 times. But it’s spaced out a lot since then. The other night I did a 1 hour cruise and it only occurred once.

I hear ya. Last attempt I made it failsafed on me about 5 times in a mile. That’s when I just decided to shitcan it.

 

[Willie]

When exactly does it failsafe? For example,
1) Idling,
2) Constant speed,
3) Accelerating,
4) Decelerating - this includes lifting to shift,
5) Some other condition I can't think of.....

at low or high rpm's or doesn't seem to matter....

 

[EvilSnake]

I hear ya. Last attempt I made it failsafed on me about 5 times in a mile. That’s when I just decided to shitcan it.

I seem to be making some ground here. Just got back from a 60mile cruise and it didn’t happen once. I sprayed some WD-40 on the ends of the shaft that holds the blade and i cleaned the throttle body (there was a small amount of blow by oil resting behind the blade). I’m really starting to think that it was just stiff after a long winter.... seems crazy but I don’t know what else to call it!

When exactly does it failsafe? For example,
1) Idling,
2) Constant speed,
3) Accelerating,
4) Decelerating - this includes lifting to shift,
5) Some other condition I can't think of.....

at low or high rpm's or doesn't seem to matter....

For me: it would happen when I let off the gas pedal while driving at low rpms. So picture you’re on the highway cruising at 60, let off the gas because you’re coming up behind someone, then your gas pedal is dead/TB is stuck closed.
I never once had the problem when I was driving at higher rpms.

 

[Willie]

I picked up a 168 early last year. I was hesitant because of everything I read about tuning it. I tune myself, but had never attempted a mono. But I got it anyways and took on the challenge. I learned a ton, basically by trial and error and tons of datalogs.

In my case, I would see failsafe only when I lifted..... sound familiar? So I focused by datalogging the instance the throttle is lifted, and fine tooth combing through the raw data, line by line, so I wouldn't miss anything. I believe I discovered the reason. It seems that KB TB's have an issue CLOSING the throttle plates -- that it's too slow. When this happens, the commanded throttle angle deviates from the actual throttle angle beyond the maximum allowable...... FAILSAFE, and this happens almost instantaneously.

Maybe it has something to do with the brass gears as many have stated, but unless someone has the guts to try to replace them with plastic or Delron (sp?), what else can we do? My solution: I used the dashpot settings to slow down the throttle blades closing when lifting the pedal. It works. But it took countless iterations to find the sweet spot between not failsafing and an objectionable throttle response when lifting.

Willie

 

[EvilSnake]

I picked up a 168 early last year. I was hesitant because of everything I read about tuning it. I tune myself, but had never attempted a mono. But I got it anyways and took on the challenge. I learned a ton, basically by trial and error and tons of datalogs.

In my case, I would see failsafe only when I lifted..... sound familiar? So I focused by datalogging the instance the throttle is lifted, and fine tooth combing through the raw data, line by line, so I wouldn't miss anything. I believe I discovered the reason. It seems that KB TB's have an issue CLOSING the throttle plates -- that it's too slow. When this happens, the commanded throttle angle deviates from the actual throttle angle beyond the maximum allowable...... FAILSAFE, and this happens almost instantaneously.

Maybe it has something to do with the brass gears as many have stated, but unless someone has the guts to try to replace them with plastic or Delron (sp?), what else can we do? My solution: I used the dashpot settings to slow down the throttle blades closing when lifting the pedal. It works. But it took countless iterations to find the sweet spot between not failsafing and an objectionable throttle response when lifting.

Willie

Very interesting. What’s also interesting is that the car was freshly tuned by lund a year ago and all last driving season I didn’t have this issue once. I’m beginning to wonder if that because my car was in winter storage- the battery of course was stone dead this spring. I installed a new battery upon bringing the car out of storage and now the car needs to “relearn”/recalibrate the throttle body.... all of which was happening on these drives I was taking where the TB kept going in to failsafe. This is the conclusion I’m coming to as when I started driving this season I couldn’t make it a mile without going in to failsafe multiple times.... now I’ve gone nearly 100miles without it occurring again.

 

[Willie]

Yes, there is a certain amount of learning that takes place and may be that was what you have been experiencing.... I don't know for sure. But if nothing else changed, it always points to the one thing that did. Hopefully, the failsafe is history. I'll keep my fingers crossed.

Willie

 

[RBB]

When exactly does it failsafe? For example,
1) Idling,
2) Constant speed,
3) Accelerating,
4) Decelerating - this includes lifting to shift,
5) Some other condition I can't think of.....

at low or high rpm's or doesn't seem to matter....

I haven't had a chance to get mine up to high RPMs. First time it failsafed was when I was doing my idle logs. 1500 and 2500 revs were fine, but on my way up to 3500 it failed around 3K. Killed the engine, restarted and tried to hit 3500 again, died around 3K.

I didn't attempt any more idle logs, just had to cruise back to the house. Only thing I definitely noticed was that it always failsafed when decelerating on a lift to shift. It also failsafed a couple more times accelerating. I think if you just let the car sit and idle it would be fine, don't have an issue there.

[bcolor=transparent]

I picked up a 168 early last year. I was hesitant because of everything I read about tuning it. I tune myself, but had never attempted a mono. But I got it anyways and took on the challenge. I learned a ton, basically by trial and error and tons of datalogs.[/bcolor]
[bcolor=transparent][/bcolor]
[bcolor=transparent]In my case, I would see failsafe only when I lifted..... sound familiar? So I focused by datalogging the instance the throttle is lifted, and fine tooth combing through the raw data, line by line, so I wouldn't miss anything. I believe I discovered the reason. It seems that KB TB's have an issue CLOSING the throttle plates -- that it's too slow. When this happens, the commanded throttle angle deviates from the actual throttle angle beyond the maximum allowable...... FAILSAFE, and this happens almost instantaneously.[/bcolor]
[bcolor=transparent][/bcolor]
[bcolor=transparent]Maybe it has something to do with the brass gears as many have stated, but unless someone has the guts to try to replace them with plastic or Delron (sp?), what else can we do? My solution: I used the dashpot settings to slow down the throttle blades closing when lifting the pedal. It works. But it took countless iterations to find the sweet spot between not failsafing and an objectionable throttle response when lifting.[/bcolor]
[bcolor=transparent][/bcolor]
[bcolor=transparent]Willie

[/bcolor]
[bcolor=transparent]Interesting Willie, and I can totally believe this. When you take a stock or even aftermarket twin blade and manually open the blades with your hand, they snap closed very quickly. I was playing around with my 168 after I installed the electronics....pushed it open, and the first thing I noticed was how much slower the blade closed when I released pressure. Again, this goes along with my experience of failsafe every single time I lift to shift.[/bcolor]​

 

[EvilSnake]

I haven't had a chance to get mine up to high RPMs. First time it failsafed was when I was doing my idle logs. 1500 and 2500 revs were fine, but on my way up to 3500 it failed around 3K. Killed the engine, restarted and tried to hit 3500 again, died around 3K.

I didn't attempt any more idle logs, just had to cruise back to the house. Only thing I definitely noticed was that it always failsafed when decelerating on a lift to shift. It also failsafed a couple more times accelerating. I think if you just let the car sit and idle it would be fine, don't have an issue there.

[bcolor=transparent][/bcolor]
[bcolor=transparent]Interesting Willie, and I can totally believe this. When you take a stock or even aftermarket twin blade and manually open the blades with your hand, they snap closed very quickly. I was playing around with my 168 after I installed the electronics....pushed it open, and the first thing I noticed was how much slower the blade closed when I released pressure. Again, this goes along with my experience of failsafe every single time I lift to shift.[/bcolor]​

Your problem is definitely sounding more and more like a tune issue.

 

[RBB]

Your problem is definitely sounding more and more like a tune issue.

That's what I was thinking as well, but Lund insists it's not....at the same time KB tells me that there's nothing wrong with my TB, so I don't know who to believe. There's a thread on the VMP 160 mono in the 13-14 section and a few of us got on the topic of the KB168. I posted about my issues there and mentioned that any time Jon Jr. hasn't done my tune I've had problems. Nothing more than that, just the facts, and it's 100% true.

Someone on the forum went and told Jr that LR was being trashed over here. He sent me a long email last week expressing his displeasure that members here are implying you don't get the same level of tuning support from LR when he isn't personally doing your tuning. Indeed that does seem to be the perception of more than a few guys, and I'm 0-2 with his other tuners. I wasn't bashing, just stating the facts....if that offends him or his calibrators then sorry, but how can you get mad over me simply speaking the truth? Everyone is so sensitive these days....

 

[Robert M]

I picked up a 168 early last year. I was hesitant because of everything I read about tuning it. I tune myself, but had never attempted a mono. But I got it anyways and took on the challenge. I learned a ton, basically by trial and error and tons of datalogs.

In my case, I would see failsafe only when I lifted..... sound familiar? So I focused by datalogging the instance the throttle is lifted, and fine tooth combing through the raw data, line by line, so I wouldn't miss anything. I believe I discovered the reason. It seems that KB TB's have an issue CLOSING the throttle plates -- that it's too slow. When this happens, the commanded throttle angle deviates from the actual throttle angle beyond the maximum allowable...... FAILSAFE, and this happens almost instantaneously.

Maybe it has something to do with the brass gears as many have stated, but unless someone has the guts to try to replace them with plastic or Delron (sp?), what else can we do? My solution: I used the dashpot settings to slow down the throttle blades closing when lifting the pedal. It works. But it took countless iterations to find the sweet spot between not failsafing and an objectionable throttle response when lifting.

Willie

^^^^^That is why I sold that 168, not that I had read a lot about tuning issues, but because I am happy with the performance of my Dual 75mm and there was no reason for me to get into something that could possibly cause an issue, especially when my car is not heavily modded.

That 168 did look brand new, that is why I bought it used from another member on here, it didn't look like someone had altered or modded it. I don't remember who I bought it from because it was quite a while back when I bought it.

I have a "spare" Dual 75mm V6 that I sent to KB to be upgraded to V9. The V9 updates were the spring in the plunger area, it is now shorter and Silver colored instead of longer and not Silver colored and there were two bushings that fit around two of the screws that attach the motor plate to the T.B., I believe those bushing help to put the motor drive gear in better alignment with the T.B. gears. I would guess that these two updates are also what make the 168mm a V9, the spring change and the motor plate bushings?

R

 

[Catmonkey]

Maybe it has something to do with the brass gears as many have stated, but unless someone has the guts to try to replace them with plastic or Delron (sp?), what else can we do? My solution: I used the dashpot settings to slow down the throttle blades closing when lifting the pedal. It works. But it took countless iterations to find the sweet spot between not failsafing and an objectionable throttle response when lifting.

It's Delrin. I've been working out the dashpot settings with the 67mm on mine since it's back on the road. I've got some idle issues because of these cams. I've about got them resolved. I'm on my 31st iteration of the tune. I'm finding I'm having to add quite a bit to the ISC values, but I get this up and down hunt for idle on coast down out of gear that I'm not sure how to log. Any ideas? I've just been slowly creeping up on the dashpot clip and driving it. Initially it was wanted to die, but after adding quite a bit of air, it's not moving much until I turn on the a/c. How much did you have to decrease the dashpot decay rates for your 168? I'm also doing this in small increments too.

 

[Willie]

I haven't had a chance to get mine up to high RPMs. First time it failsafed was when I was doing my idle logs. 1500 and 2500 revs were fine, but on my way up to 3500 it failed around 3K.

This was EXACTLY my experience with mine. All I did to correct this was to change my dashpot settings, but changing the entire rpm range by the same multiplier did NOT work. That's because at lower rpm's, failsafe does not occur. It occurs only at mid to high rpm's. Also, depending on if you failsafe when decelerating and/or free revving at a standstill, there is another setting that needs to be changed. It's called "Dashpot Min mph". Once I fine tuned my dashpot to prevent failsafe when shifting, I still experienced it when just free revving. Changing the Dashpot Min mph solved this.

But I consider changing the dashpot settings as a WORKAROUND. It really does nothing to solve the problem of a slow closing throttle blade, it just prevents failsafe.

Your problem is definitely sounding more and more like a tune issue.

Honestly, I believe the problem is mechanical. Like I just mentioned above, it's a slow closing throttle blade. I even tried clocking the spring tighter with hopes that it would help snap the blade back quicker, but this did not work.
---------------------
If you guys tune yourself, message me and I'll give you my dashpot settings to try. If you don't, then ask your tuner if your file uses stock dashpot settings. I would venture to guess that it does. But by asking, you will know conclusively if my workaround may help.

Willie

 

[Willie]

It's Delrin.

Thanks!

.... I'm finding I'm having to add quite a bit to the ISC values, but I get this up and down hunt for idle on coast down out of gear that I'm not sure how to log. Any ideas?

The first thing I'd try is to disable Coasting Fuel Shutoff. Mine is turned off.

I've just been slowly creeping up on the dashpot clip and driving it. Initially it was wanted to die, but after adding quite a bit of air, it's not moving much until I turn on the a/c. How much did you have to decrease the dashpot decay rates for your 168? I'm also doing this in small increments too.

These are my current dashpot settings:

Willie

 

[RBB]

This was EXACTLY my experience with mine. All I did to correct this was to change my dashpot settings, but changing the entire rpm range by the same multiplier did NOT work. That's because at lower rpm's, failsafe does not occur. It occurs only at mid to high rpm's. Also, depending on if you failsafe when decelerating and/or free revving at a standstill, there is another setting that needs to be changed. It's called "Dashpot Min mph". Once I fine tuned my dashpot to prevent failsafe when shifting, I still experienced it when just free revving. Changing the Dashpot Min mph solved this.

But I consider changing the dashpot settings as a WORKAROUND. It really does nothing to solve the problem of a slow closing throttle blade, it just prevents failsafe.



Honestly, I believe the problem is mechanical. Like I just mentioned above, it's a slow closing throttle blade. I even tried clocking the spring tighter with hopes that it would help snap the blade back quicker, but this did not work.
---------------------
If you guys tune yourself, message me and I'll give you my dashpot settings to try. If you don't, then ask your tuner if your file uses stock dashpot settings. I would venture to guess that it does. But by asking, you will know conclusively if my workaround may help.

Willie

So you think the problem is mechanical, but this mechanical problem is inherent to all KB168s? In that case, it would seem it's up to the tuner to make the proper adjustments.

 

[Willie]

....I'm on my 31st iteration of the tune....

You don't want to know how many I've gone through, lol..... I have not counted, but my guess is around 200....

Willie

 

[Willie]

So you think the problem is mechanical, but this mechanical problem is inherent to all KB168s?

Well, by reading other's symptoms, I am thinking that this issue is inherent, even on the 75mm.... it seems that failsafe on lifting (while shifting and free revving) is a common theme.

In that case, it would seem it's up to the tuner to make the proper adjustments.

I am not in contact with any of the big-name tuners, so I don't know whether they have tried what I have. Therefore, I don't know if they've even thought to try what I have.

I have come up with a modified tune solution but I also believe that it is just a workaround. Any tuner can change the dashpot settings to prevent the failsafe, but in my opinion, this is not a solution, only a band-aid. But whatever I think, if a band-aid works when there is no other solution, it sure is better than nothing.

Willie

 

[Robert M]

You all have lost me, but I want to learn......

I know what a dashpot does on a carburetor, it slows the throttle blades from slamming shut too quickly, most were attached to a bracket and the throttle linkage would rest against it while the throttle blades were closing and it was adjustable.

The only "mechanical" place I can think of for this function in a KB TB is that spring and plunger inside of that threaded brass piece, is that the dashpot function in the TB?

R