Something odd about my bored throttle body

[Knucklehead97]

Renix engine, of course. With a bored out throttle body that I got from another member AGES ago (probably 5 years)

 

No idea who made it.

 

But I've been having a rough idle on my Jeep, and I had a rough idle with my last Jeep that I had this throttle body on. I've spent months and 100's of $'s trying to figure it out. Just did a smoke test and there was no vacuum leaks in my system, that was the final test since I finally built a smoke machine. But I looked at the throttle body and realized a difference it had compared to the stock TB.

 

There's a plastic plug squeezed into the passage way for the hidden star-bit air bleed (or whatever it's called). Does anyone else have a bored out TB like this? Or could this be the reason my Jeep always seems to be struggling for air?

 

 

[Ωhm]

My bet, its a engineering TB. Good time for a cruiser tip.

RENIX THROTTLE BODY BUTTERFLY ADJUSTMENT

[Knucklehead97]

1 minute ago, Ωhm said:

My bet, its a engineering TB. Good time for a cruiser tip.

RENIX THROTTLE BODY BUTTERFLY ADJUSTMENT

What is an engineering TB? And I have done the butterfly adjustment and just double-checked the TPS. It's showing proper readings. Would you recommend I remove the plug?

[Ωhm]

1 minute ago, Knucklehead97 said:

Would you recommend I remove the plug?

No

Engineering TB have extra things for instrumentation stuff. Used for development and design. Just a guess.

[fiatslug87]

None of my TBs, bored or not, have a plastic plug in that spot. Mine also do not have that Torx "plug", they have a flat plug recessed in that place.

[Warren Mohler]

I would certainly try removing it, proper throttle adjustment would require this air bleed I would think, looking at bleed screw it appears to be on the verge of falling out, remove that plug and adjust idle to spec and see what happens you can always put it back

[Warren Mohler]

17 minutes ago, fiatslug87 said:

None of my TBs, bored or not, have a plastic plug in that spot. Mine also do not have that Torx "plug", they have a flat plug recessed in that place.

A flat plug is anti tamper cover that is easily removed to access torx screw

[Knucklehead97]

Well. I ended up removing it because I was driving and the rough idle just frustrated me to the point of no return. Amazingly enough, the engine runs PHENOMENALLY now. My idle is a little high (900 or so) but I can resolve that with some toying around. I have more seat-of-the-pants power and the engine sounds much healthier. Plus it does not bog down now when I run my headlights and heat on high. 

[Warren Mohler]

Turn your bleed screw in till proper idle speed s achieved, you may want to clean that passage and screw before doing so, bleed screw has an O-ring on it to keep in position and seal

[Ωhm]

2 hours ago, Knucklehead97 said:

Well. I ended up removing it because I was driving and the rough idle just frustrated me to the point of no return. Amazingly enough, the engine runs PHENOMENALLY now. My idle is a little high (900 or so) but I can resolve that with some toying around. I have more seat-of-the-pants power and the engine sounds much healthier. Plus it does not bog down now when I run my headlights and heat on high.

Good call on NOT listening to me. I learned something today.

[Knucklehead97]

2 hours ago, Ωhm said:

Good call on NOT listening to me. I learned something today.

So did I! Upon looking at the TB very closely, I noticed the reason why the creator of this bored out TB had put that plug in; they must have thinned the wall out too much on the side with the hole for the air bleed valve because the valve does not seat very tightly anymore. I'm going to reset my butterfly valve and TPS to see if this helps with the higher idle. But if it doesn't, I'm not worried about it. I'd rather this idle than it trying to stall out all the time.

[cruiser54]

That was a common practice years ago. Epoxy has sometimes been used to fill that hole also.

Watch carefully when turning that air screw in that it doesn't hit the butterfly. 

[Knucklehead97]

1 hour ago, cruiser54 said:

That was a common practice years ago. Epoxy has sometimes been used to fill that hole also.

Watch carefully when turning that air screw in that it doesn't hit the butterfly. 

That's what I noticed when I was adjusting it. Why was it a common practice? What did it solve?

[54bobby]

On 1/22/2020 at 2:00 PM, Knucklehead97 said:

Renix engine, of course. With a bored out throttle body that I got from another member AGES ago (probably 5 years)

 

No idea who made it.

 

But I've been having a rough idle on my Jeep, and I had a rough idle with my last Jeep that I had this throttle body on. I've spent months and 100's of $'s trying to figure it out. Just did a smoke test and there was no vacuum leaks in my system, that was the final test since I finally built a smoke machine. But I looked at the throttle body and realized a difference it had compared to the stock TB.

 

There's a plastic plug squeezed into the passage way for the hidden star-bit air bleed (or whatever it's called). Does anyone else have a bored out TB like this? Or could this be the reason my Jeep always seems to be struggling for air?

 

 

not to threadjack but i will. 

on the lower photo, what is the very small hole on the inside of the carb throat for? my 87 2.5 has been, what seems to be flooding out when trying to be restarted after it's warm and fuel squirts up out of this whole.

[cruiser54]

7 hours ago, Knucklehead97 said:

That's what I noticed when I was adjusting it. Why was it a common practice? What did it solve?

 

I haven't a clue why. 

[AeroNautical]

On 1/22/2020 at 2:00 PM, Knucklehead97 said:

Renix engine, of course. With a bored out throttle body that I got from another member AGES ago (probably 5 years)

 

No idea who made it.

 

But I've been having a rough idle on my Jeep, and I had a rough idle with my last Jeep that I had this throttle body on. I've spent months and 100's of $'s trying to figure it out. Just did a smoke test and there was no vacuum leaks in my system, that was the final test since I finally built a smoke machine. But I looked at the throttle body and realized a difference it had compared to the stock TB.

 

There's a plastic plug squeezed into the passage way for the hidden star-bit air bleed (or whatever it's called). Does anyone else have a bored out TB like this? Or could this be the reason my Jeep always seems to be struggling for air?

 

 

 

 

Oh man, I remember selling this TB to you years ago. So glad to see it's still being used. The TB was bored by Leigh Performance Machines, and when I ran it, I didn't have those issues, but that's not to say that little plug should be there. I figured he had put it there for some reason, and never really messed with it. Hopefully you figure out the issue, bud. 

[cruiser54]

That's the way Jeff did them. I ended up pulling the plug from the top and using the screw on the side for idle air adjustment. There was something about the needle tip being too long and getting in the way of the butterfly. IIRC, I shortened it. 

[Knucklehead97]

12 hours ago, PFCLeist said:

Oh man, I remember selling this TB to you years ago. So glad to see it's still being used. The TB was bored by Leigh Performance Machines, and when I ran it, I didn't have those issues, but that's not to say that little plug should be there. I figured he had put it there for some reason, and never really messed with it. Hopefully you figure out the issue, bud. 

It's been running 10x better since I removed the plug. Still a lil rough of an idle but at least now it sits at a good number and doesn't bog down. Also has a lot more power and my cowl intake is louder due to the amount of air the engines getting. I had to use my winch to pull myself out of a ditch last weekend and the engine didn't bog at all. Usually using the winch it bogs down and tries to die.

[Pete M]

On 1/24/2020 at 5:22 PM, 54bobby said:

not to threadjack but i will. 

on the lower photo, what is the very small hole on the inside of the carb throat for? my 87 2.5 has been, what seems to be flooding out when trying to be restarted after it's warm and fuel squirts up out of this whole.

 

2.5 is a throttle body injection motor and has a different TB. you should include a shot of yours so we can tell what you mean.  

[cruiser54]

52 minutes ago, Knucklehead97 said:

It's been running 10x better since I removed the plug. Still a lil rough of an idle but at least now it sits at a good number and doesn't bog down. Also has a lot more power and my cowl intake is louder due to the amount of air the engines getting. I had to use my winch to pull myself out of a ditch last weekend and the engine didn't bog at all. Usually using the winch it bogs down and tries to die.

Have you exposed the Torx headed screw on the side? 

[Knucklehead97]

8 hours ago, cruiser54 said:

Have you exposed the Torx headed screw on the side? 

Yes. I use it to adjust. Running about 750-800 rpm, 600 in drive

[cruiser54]

So, what's the problem at idle then? 

[Knucklehead97]

Not much of one anymore. Sorry if I seemed to hint that there was still an issue. Jeeps running better than it has in a long time now. Just still has a kind of rough idle and a slight miss when warmed up. Pretty sure it's the low compression I found in #3 and #6 cylinder. Only 95 psi.

[Eagle]

On 2/8/2020 at 1:26 PM, Pete M said:

not to threadjack but i will. 

on the lower photo, what is the very small hole on the inside of the carb throat for? my 87 2.5 has been, what seems to be flooding out when trying to be restarted after it's warm and fuel squirts up out of this whole.

 

2.5 is a throttle body injection motor and has a different TB. you should include a shot of yours so we can tell what you mean.  

 

In fact, the Renix 2.5L is so much different from the Renix 4.0L that you should start a separate thread to discuss your issue.