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General Forums => The Mess Hall => Topic started by: bukdwn on December 26, 2011, 07:07:20 PM
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Maybe you guys will remember but I'm still trying to get the idle correct. I've installed a 4.0 throttle body on my 2.4 YJ. I removed the 4.0 IACV motor housing and did install my original 2.5 housing. At first I thought the 4.0 installed housing ran better but after talking to you guys, it would be better if i reinstalled the 2.5 housing and the 2.5 IAC valve. ( I like to see why things don't really work. ) So let me recap on what i did so hopefully someone could figure this out. I bought a 4.0 throttle body and installed it. I left the IAC valve housing (with the 4 tamper proof bolts) installed on the throttle body and installed my original 2.5 IAC motor. The engine ran pretty good i thought! but people told me this would reduce my fuel economy and was just not correct. So i thought i would go out and do some other maintenance under the hood and also change out the throttle housing. I wanted to see what the charcoal canister was all about and also clean the exterior of it. I unhooked the 2 vacuum lines from it and removed the canister to clean. I thought no big deal, i would start the engine and see what it would run like with the canister removed. Bad things started happening to my jeep from that day on. The jeep started but would barely run, about 2 hundred RPM's . i turned it off and cleaned the canister. reinstalled the system and went to fire it up. Started but barely ran again, (very low RPM's ) I turned it off and restarted it and it ran fine. My jeep is not my daily driver so it sat for a day then i drove it up town. All was good! then went to start it one afternoon and it would barely idle again, turned it off and restarted just fine.. So i thought maybe this could be from the 4.0 IACV housing being installed. got my tools out and changed it to the correct 2.5 housing, put everything back and went for a drive. The engine ran fine except for the idle. when i come to a stop the engine idle is up around 1300 then slowly comes down to correct idle. This has been going on for awhile now. I removed the battery cables for a day. There's not any codes that are coming up. The engine runs perfect at all speeds and RPM's. SO. i went and looked at the installation instruction on installing the IACV. The instructions state=[ Pintle position of the replacement IACV unit must be checked before installing in throttle body. if pintle is extended too far, internal damage to the IACV unit may occur]. Has anybody read these instructions and understand how to adjust the pintle length. I've tried :brick: Really appreciate any info you might have.
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hook up the IAC motor to the connector before installing it, put the key into run position, wait 2 or 3 seconds and take the contac off, the pintle should reset into the correct position to be installed - the instructions you posted are for the use of the IAC motor the first time, if it's over extended you could damage the internals (stepper motor assembly) by tightening the bolts, the pintle would retract once you set the contact on run position just like prior to starting the engine, once it's running would be pushed out to reduce the airflow and set the correct idle.
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OK, That makes sense! I did purchase a new one and unfortunately i pulled the pintle out and over extended it. The pintle came completely off. I believe i might have ruined it??? I did reinstall the pintle and screwed it all the way in. the engine still idles the same. Is there a way to fix the IACV or should i purchase a new one? Thank you for the install procedure before installing the motor.
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OK, That makes sense! I did purchase a new one and unfortunately i pulled the pintle out and over extended it. The pintle came completely off. I believe i might have ruined it??? I did reinstall the pintle and screwed it all the way in. the engine still idles the same. Is there a way to fix the IACV or should i purchase a new one? Thank you for the install procedure before installing the motor.
does it idle high when it's cold and then goes down? if yes then you didnt ruin it.
you could have a vac leak or
you might want to have a look at the butterfly adjusting screw - unscrew it (you need a 2.5mm hex allen) until it's off the lever, put a piece of white paper between the screw and the lever and screw in until it catches, go in 1/8 to 1/4 turn past that (until it touches and pushes slightly) - open the throttle and make sure the butterfly doesn't catch onto the t/b bore (you can feel if it does), go little steps (screw in) until it operates freely - if someone messed with the screw and it's open too much will have the results you describe, would come down to 1500 or about there and then slowly would go below 1000 rpm, usually it would rest a bit at about 1000 and then go to idle speed in a second or 2. Make sure there are no vac leaks before you tackle this one, if you have a spacer you don't need to take the t/b off, i can't remember if there's enough room to do it without one.
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Sharpxman, Thanks for the reply. The idle is the same, cold or warm engine. I've checked and checked the Vac lines over and over. All good, Excellent shape. The idle speed screw is only accessed from the bottom of the throttle body. It must be removed to adjust it. Next time i remove the throttle body, i'm going to remove the allen screw and install it from the top so as to be able to adjust it if ever needed. Not sure why i would need to adjust it if the motor is maintenance correctly. I believe the screw has not been adjusted previously before i owned it. you can see that the thread lock has not been disturbed. Even if i push the throttle arm down hard to the stop screw after burping the throttle the idle stays up around 1400 RPM's then starts to fall slowly and comes to rest at 8500-9000 rpm's From 1400 to 8500 or so it takes about 4-5 seconds. When starting the engine cold, the idle does stay up around 16 to 1700 for about 10-12 seconds before resting at normal idle.
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to me it sounds like either a vac leak or the butterfly not closing enough, what you describe with the idle at cold is normal so i think the IAC valve operates properly. I had somewhat the same problem you describe and i fixed it by adjusting the butterfly screw properly, but in my case i have a 64mm t/b which was taken apart to be bored and i probably set the screw wrong when i reassembled it, it doesn't take much though, from what i remember i had to just unscrew less than a 1/4 turn to get it right. However since yours was not touched i would focus on the vac leak or maybe something related to the canister, can't think of anything else.
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Thanks SHARPXMAN. So , I think i'm going to remove and replace the Vac plastic lines and the hoses. Have you come across any good parts replacement for this prodject. I like having the plastic lines so as to direct were they are going and also to keep from laying on everything. I seen guys replace with silicone line, yes it does work but the amount of Zip ties are ridicules. Is there a company that sells like OE replacement ones?
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Thanks SHARPXMAN. So , I think i'm going to remove and replace the Vac plastic lines and the hoses. Have you come across any good parts replacement for this prodject. I like having the plastic lines so as to direct were they are going and also to keep from laying on everything. I seen guys replace with silicone line, yes it does work but the amount of Zip ties are ridicules. Is there a company that sells like OE replacement ones?
could also be a vac leak at the manifold gasket (cyl head side) if you had it off at some point might want to check the seating or make sure the bolts are not loose.
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Also, Im thinking about the Canister. My jeep is a 95 YJ. I cleaned the exterior of the canister about a month ago. I looked at it the other day and saw some liquid on the bottom half of it, wiped my finger across it and it smelled like engine oil not fuel. I don thave any oil leeks what so ever under the hood. I'm going to look into this further today and see what is up. Junk yards are far and between around here and to find a Wrangler in one is unheard of. Do you now of a vehicle that would have the same set up as the 95 canister?
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I looked at the manifold gasket and have sprayed some carb cleaner around that area before with no change. I will inspect it again, never know! Thanks for the help
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Also, Im thinking about the Canister. My jeep is a 95 YJ. I cleaned the exterior of the canister about a month ago. I looked at it the other day and saw some liquid on the bottom half of it, wiped my finger across it and it smelled like engine oil not fuel. I don thave any oil leeks what so ever under the hood. I'm going to look into this further today and see what is up. Junk yards are far and between around here and to find a Wrangler in one is unheard of. Do you now of a vehicle that would have the same set up as the 95 canister?
remove and plug the line going from the intake to that canister and see if it improves at all, if it does then you might have a vac leak there.
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remove and plug the line going from the intake to that canister and see if it improves at all, if it does then you might have a vac leak there.
Ok, Removed the Vac line and still ran the same. I've been trying everything. I recently replaced the Fuel pressure regulator with a new one. Bought the better one from a US manufacture, not sure who though. The old one had (2) o-rings and the new one had only one. On the front of the regulator not the side with the vac. hose connection. The old one has a o-ring on the tip and the new one did not come with a o-ring. The new regulator on the tip has a band around it. It is part of the casting. I tried installing it both ways ( with old o-ring installed on it and with out the old o-ring installed) I could not tell any difference in how the engine ran. How does the FPR work really.
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Ok, Removed the Vac line and still ran the same. I've been trying everything. I recently replaced the Fuel pressure regulator with a new one. Bought the better one from a US manufacture, not sure who though. The old one had (2) o-rings and the new one had only one. On the front of the regulator not the side with the vac. hose connection. The old one has a o-ring on the tip and the new one did not come with a o-ring. The new regulator on the tip has a band around it. It is part of the casting. I tried installing it both ways ( with old o-ring installed on it and with out the old o-ring installed) I could not tell any difference in how the engine ran. How does the FPR work really.
if you don't have the o-ring on that nipple there won't be any pressure in the rail so it won't run, my bet is you have the old o-ring stuck in there and that's why is running still. what p/n is your fpr, there are a few that are out of spec as far as using them in a YJ (meant for different fuel pressure) but they have the same mechanical dimensions.
Bought the better one from a US manufacture, not sure who though.
that's funny, how did you come to qualify this FPR you bought as a "better one"? - is it shiny compared to the old one? :lol:
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That did sound dumb, right. I pretty sure when i bought the new FPR, i was given a choice of two different ones. Expensive and more expensive. I think one was a china made and the one i bought say's its made in USA. You are right about the o-ring stuck inside. I went to Napa and looked at one in the box and it had 2 o-rings. Got home, removed the FPR and YES the oring was stuck inside. All good. Atleast that is fixed!! So i'm wondering if this could give more info on what is going on with the idle. I noticed there is a lot of condensation / water coming out of the tail pipe. My son said that when i leave the driveway there is a stream of water coming out of the tail pipe. What do you think? Newer exhaust muffler and the cat has half the honey comb removed. Not really sure why i did this to the cat back then, i think i thought it would flow better or something.
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there's always water/steam coming out when the exhaust is cold, that is normal.
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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?
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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.
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Took it out and saw that the o-ring was fine. Still a mystery though.
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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.
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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 .
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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
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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.
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by what you describe you did everything right so i'm out of ideas
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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.
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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.
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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).
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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.
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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.
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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.