Topic: IACV Valve- Distance measurement question?

[bukdwn]

Thanks for the reply's sharpxman.  Yes some water/condensation is normal but it will leave a puddle on the ground.  More than normal lately.   I'm thinking that it might be the IACV  O-ring that is on the motor.    When i remove the IAC and plug it in to the wiring and turn the ket on,  What should i look for?

[sharpxmen]

Thanks for the reply's sharpxman.  Yes some water/condensation is normal but it will leave a puddle on the ground.  More than normal lately.   I'm thinking that it might be the IACV  O-ring that is on the motor.    When i remove the IAC and plug it in to the wiring and turn the ket on,  What should i look for?

the piston would move in and out and settle at a position, there's no need to take it out though. I doubt is the o-ring.

[bukdwn]

    Took it out and saw that the o-ring was fine.    Still a mystery though.   

[sharpxmen]

    Took it out and saw that the o-ring was fine.    Still a mystery though.   

put back your stock t/b and see if it's better, if with the 2.5L t/b is fine then there's something wrong with the one you're using, if not keep chasing the vac leak.

[bukdwn]

sharpxman   Yesterday i decided to install the old TB,  Back to stock.    At first the engine idle was still the same so i unplugged the AIS from the plug.   ( Just to clarify, The idle will return to normal  after 4-5 seconds) with the 4.0 TB.   So after installing the 2.5 TB when i unplugged the motor and chopped the throttle a few times and plugged the motor back in, everything was fine.      Turned off the engine and re started, Everything is correct with the idle.    I don't think so but, could it be the 4.0 TB .

[sharpxmen]

sharpxman   Yesterday i decided to install the old TB,  Back to stock.    At first the engine idle was still the same so i unplugged the AIS from the plug.   ( Just to clarify, The idle will return to normal  after 4-5 seconds) with the 4.0 TB.   So after installing the 2.5 TB when i unplugged the motor and chopped the throttle a few times and plugged the motor back in, everything was fine.      Turned off the engine and re started, Everything is correct with the idle.    I don't think so but, could it be the 4.0 TB .

i can think of a few things
 - t/b is crooked or has been hit in one of the corners and it doesn't seal on the intake
 - if you're reusing the old gasket from the 4.0 could be pressed in (the intake opening impression from the 4.0 intake) and it does not match your opening
 - the IAC housing was pressed against the intake and did not seal properly (i might be wrong but i think you replaced the housing with the t/b installed, i somehow remember that some of the housings extend past the bottom pf the t/b and if it was installed prior to the housing

[bukdwn]

Man, This is killing me. I like working on my jeep but i like when i solve the problems.
    Ok. Everything back to stock...... This morning i went out and started the jeep. Everything was fine.  Idled just like it should.   I drove it around last night and drove fine ( except for the lac of response ) .    So i decided to remove the 2.5 TB and re- install the 4.0 TB.  I took the 2.5 TB into my shop and removed all the parts and installed them on the 4.0 TB. I completely cleaned all parts, removed the old RTV and such.  Went down to the local Napa and picked up a new TB Gasket. the old one i was using was from the original 2.5 TB. I wanted to take that question out of the problem.   
  Installed the 4.0 TB  put back on the filter box. Made sure everything was hooked up and started the engine........    Ran just like it did before.           If i unplug the AIS while the engine is running at idle, i can run up the rpm's and the throttle will come down like it is suppose to.  I have not ran it long with the AIS unplugged, but long enough to know that the idle is correct with it unplugged.   Once i plug it back in, i let it idle for a few seconds then bring up the RPM's and  once again same idle problem.      If i let the engine just run for a minute or two and then chop the throttle, it will come down on idle pretty good.  But anything more than one chop, same idle problem.         
          SHARPXMAN,   Good call on the smashed corners thought. unfortunately not my case.   
                              Old gasket was from the 2.5 TB and was just replaced with a new one. 
                               AIS/IAC  housing was installed with the TB removed for cleaning.                         
       Also want to mention  that i did not use any silicone/RTV on the surfaces. Just installed the new filter dry.                                             

[sharpxmen]

by what you describe you did everything right so i'm out of ideas

[bukdwn]

Man, This is killing me. I like working on my jeep but i like when i solve the problems.
    Ok. Everything back to stock...... This morning i went out and started the jeep. Everything was fine.  Idled just like it should.   I drove it around last night and drove fine ( except for the lac of response ) .    So i decided to remove the 2.5 TB and re- install the 4.0 TB.  I took the 2.5 TB into my shop and removed all the parts and installed them on the 4.0 TB. I completely cleaned all parts, removed the old RTV and such.  Went down to the local Napa and picked up a new TB Gasket. the old one i was using was from the original 2.5 TB. I wanted to take that question out of the problem.   
  Installed the 4.0 TB  put back on the filter box. Made sure everything was hooked up and started the engine........    Ran just like it did before.           If i unplug the AIS while the engine is running at idle, i can run up the rpm's and the throttle will come down like it is suppose to.  I have not ran it long with the AIS unplugged, but long enough to know that the idle is correct with it unplugged.   Once i plug it back in, i let it idle for a few seconds then bring up the RPM's and  once again same idle problem.      If i let the engine just run for a minute or two and then chop the throttle, it will come down on idle pretty good.  But anything more than one chop, same idle problem.         
          SHARPXMAN,   Good call on the smashed corners thought. unfortunately not my case.   
                              Old gasket was from the 2.5 TB and was just replaced with a new one. 
                               AIS/IAC  housing was installed with the TB removed for cleaning.                         
       Also want to mention  that i did not use any silicone/RTV on the surfaces. Just installed the new gasket dry.                                             

[bukdwn]

Sharpxman,,    Thanks you for all the input.    I'm sure it wouldn't be the TB, Not much could go wrong with it.  Besides the 2 outer bearings.   I'm thinking something electrical.   

[sharpxmen]

Sharpxman,,    Thanks you for all the input.    I'm sure it wouldn't be the TB, Not much could go wrong with it.  Besides the 2 outer bearings.   I'm thinking something electrical.   

if it was electrical would happen with both though, so to be honest the only thing i can relate this to (given that all the info you provided) is something related to the IAC - but since you mentioned that if you unplug the motor when installed on the 4.0 it returns to idle just like the 2.5 with the motor plugged i can only think that when you install it on the 4.0 t/b it somehow binds, long shot but like i said, based on all your tests and results that's the only thing i can come up with (maybe the mounting face of the housing on the t/b is curved and the IAC pintle binds).

[k]

I too have had the same problem with mine since doing the TB swap.  At start up it revs up higher than it did with the 2.5, then comes back down to normal in a few seconds.  I am debating buying new gaskets for the TB, spacer, and IAC in the event that there might be "memory" to one or a slight rip in one of them.  Even thinking of going to the dealership and buying a OEM IAC, just to be sure. (I did break the old one I think.  Pulled it out after a backfire from something else and it was all disconnected.  Screwed it back together, but wasn't sure that it would not all come part again, so I replaced it.)

Same issue it sounds like you are having though, once it is running, it is OK.

[SDWE61988]

I have had this problem for a while also.  Even after the rebuild the idle is still not right. I replaced the IAC motor and it did not make a difference. I will have search for a vac leak or try the set screw adjustment.

[SDWE61988]

I went home a couple weeks ago and performed an adjustment on the set screw on the tb.  it still revs when I first start it, but not as high.  it now settles to idle much better when I shift out of gear.  I think that was most of my problem.  As far as the vacuum leak, I do not think I have one in my case.  a test i performed was to have the engine running at idle and then I  covered the intake to starve the engine of air.  It stalled almost instantly.  I am thinking if there was a vacuum leak it would have lastest longer or not stalled at all.