Topic: how to make go my throttle of 62 mm

[dledle 16]

Hello,
 
I posed today a throttle body of 62 mm (more 67% Of air)
 on my 2.5 tj. The origin makes 48 mm.

 I have to increase the collecting support of 55 mm to 62 Misters, not easy...
 I am very disappointed because that does not go better. Carburation seems really too poor, and the modes are puffing.

Is that normal? What do I have to make?
 :(  :(
Thank you for your answer...

Pascal R      

[Jeffy]

Bigger is not always better, which is why I don't recommend boring out a TB on a 2.5L unless you're going a bunch of other stuff.  If you haven't already reset you computer by disconnected the battery for a few minutes.  Then if you haven't already put the stock airbox back on.  Hopefully that will smooth things out.  The engine's probably running really lean.

[dledle 16]

In fact, that goes but not better! With each immobilization, the idle remains with 1500 rpm during a few seconds before being stabilized with 700 rpm abruptly (not pleasant).

The engine seems to lack gasoline in recovery and when the throttle is open into large.

Should the injectors be changed?
Is it necessary to change the pressure of the pump?
Is it necessary to play on the temperature sensor of the engine?

I do not know what the others do...!!!

[Jeffy]

The high idle means there is a vacuum leak someplace.

[dledle 16]

The machining (up to 62 mm) of the throttle of 4.0 L is inevitably cylindrical.
It lets appear a very light net of light, between the body and the periphery of the shutter.
 On the bodies of origin, central machining is spherical, to marry the rotation of the shutter.
That causes surely my problem of idle with 1500 rpm.

I do not believe to have elsewhere escape of air  
 
Pascal :wink:  :wink:  :wink:

[StefanBidi]

I think means in the vacuum hoses going out of the intake manifold.  If I remember correctly, there should be 3 of them.  The hoses are attached right under the throttle body facing the driver side of the vehicle.

[dledle 16]

All hoses are still attached  under the throttle body.

Thank you          Pascal R

[Jeffy]

So you made the TB the same bore all the way through? If that's the case, and there is a gap then you went too far and now probably need to make a new butterfly valve.  When you bore a TB you should have stayed below the butterfly valve so as not to change the dia. at the mating surface.  When the engine is idling the butterfly valve should be closed and air should be passing through the AIS only.

[dledle 16]

I have a bored TB (same bore of 62 mm all the way through) with a new butterfly valve of 62,2 mm.

Can be that I can regulate the thrust of the shutter, so that it is closed again more.

[Jeffy]

If the butterfly valve is not closed you can try adjusting the stop for the valve on the side of the throttle body.  Try adjusting that to make the butterfly close.  It needs to close.