R-2 high rev

[Chalkstk]

My first guess is that it is heat related as you have already probably considered. I may have a way to find the problem. Use a heat gun and heat up each of the sensors seperately. Once the sensor is up to temperature, try starting and see if it revs. If it does go to the next sensor and so on. If it doesn't, you may have found the problem. That problem could be the sensor or the connection. I would even try heating up the fuse and relay box a little as they also build a little heat and even the white plugs behind the drivers seat where the computer is. LOL

Lenny

Lenny,

It was running fine after I'd get it to idle, all day. But yesterday, it worked start and stop, twice. The third time it high revved and that is after it is warmed up. Just another quirk. Is the ECU under the drivers seat? All I saw and adjusted to 41 psi was the the fuel pump gage. Is that setting alright? It was originally set to about 21 psi.

So it doesn't sem to be a cold problem, but after it sits for any length of time. The kill switch off and on does nothing either. So it doesn't seem to be a default problem does it?

THX again for all the tips. I sure am learning what machine looks like under that low dump box that I crack my head on everytime I become a contortionist getting underneath it.

Frankie

[Guest Lenny]

Lenny,

It was running fine after I'd get it to idle, all day. But yesterday, it worked start and stop, twice. The third time it high revved and that is after it is warmed up. Just another quirk. Is the ECU under the drivers seat? All I saw and adjusted to 41 psi was the the fuel pump gage. Is that setting alright? It was originally set to about 21 psi.

So it doesn't sem to be a cold problem, but after it sits for any length of time. The kill switch off and on does nothing either. So it doesn't seem to be a default problem does it?

THX again for all the tips. I sure am learning what machine looks like under that low dump box that I crack my head on everytime I become a contortionist getting underneath it.

Frankie

The ECU on mine is behind the drivers seat about shoulder blade level on the front side of the fire wall. It's under a black plastic cover about 6" x 6" or so and about 2" deep. 21 psi is wrong, 41 is more like it probably more wouldn't hurt. I thinking about 50-52. Thats is about where i'm going to set mine when I fire it up in the next few days. Been down doing things to it since Thanksgiving. By the way, you can unplug the IAC ( on the throttle body) and it should run fine but it will depend on the idle set screw to dictate idle RPMs. If it fixes the problem, you know it's either in its connections, wiring, a bad IAC, or a bad computer (which I dought). When I had a speedo problem, I went to my dealer which I have (or had, he dropped Joyner) a good relationship with. He let me set my Trooper next to one of his and I switched the RPM sensor (on the right side of the engine facing it from the rear and just back from the front (front of Trooper) of the engine at the bell housing), switched speedos and computer. Of course, each one at a time. In my case it was the computer, everything worked when I switched it. I damaged it by not unplugging it and removing it when I welded on the Trooper. If you could find a Trooper to do that with, it would be a huge step towards finding the problem. Of course switch all the sensors one at time. You also will then know what it is not at least.

Lenny

[Chalkstk]

The ECU on mine is behind the drivers seat about shoulder blade level on the front side of the fire wall. It's under a black plastic cover about 6" x 6" or so and about 2" deep. 21 psi is wrong, 41 is more like it probably more wouldn't hurt. I thinking about 50-52. Thats is about where i'm going to set mine when I fire it up in the next few days. Been down doing things to it since Thanksgiving. By the way, you can unplug the IAC ( on the throttle body) and it should run fine but it will depend on the idle set screw to dictate idle RPMs. If it fixes the problem, you know it's either in its connections, wiring, a bad IAC, or a bad computer (which I dought). When I had a speedo problem, I went to my dealer which I have (or had, he dropped Joyner) a good relationship with. He let me set my Trooper next to one of his and I switched the RPM sensor (on the right side of the engine facing it from the rear and just back from the front (front of Trooper) of the engine at the bell housing), switched speedos and computer. Of course, each one at a time. In my case it was the computer, everything worked when I switched it. I damaged it by not unplugging it and removing it when I welded on the Trooper. If you could find a Trooper to do that with, it would be a huge step towards finding the problem. Of course switch all the sensors one at time. You also will then know what it is not at least.

Lenny

Lenny,

I think you are forgetting about apples and oranges I have a Renegade, 3 banger and you have a Trooper, 4 banger. I do not see any ECU behind or under drivers seat. And what does the IAC look like? Could you ask someone else where the ECU is on the R-2? I don't know what thread to use for that question. It would be nice if the manual had pics of the engine that had an ABC of marking out each sensor and other components as to location and what they look like. I don't mind learning, but feel without a mentor I'm grasping at straws by guessing what does what and where it is. Not stupid, just ignorant or uninformed.

Didn't realize I had to be a tech to own and enjoy driving my UTV

Frankie

[ricksrb]

Lenny,

I think you are forgetting about apples and oranges I have a Renegade, 3 banger and you have a Trooper, 4 banger. I do not see any ECU behind or under drivers seat. And what does the IAC look like? Could you ask someone else where the ECU is on the R-2? I don't know what thread to use for that question. It would be nice if the manual had pics of the engine that had an ABC of marking out each sensor and other components as to location and what they look like. I don't mind learning, but feel without a mentor I'm grasping at straws by guessing what does what and where it is. Not stupid, just ignorant or uninformed.

Didn't realize I had to be a tech to own and enjoy driving my UTV

Frankie

Did you try adjusting the idle screw out? you keep mentioning its backed off all the way.As lenny mentioned ECU reads position of sensor,if not reading any it may be compensating.Hope someone else chimes in regarding my thoughts because that is what i was told by tech at joyner.

[Guest Lenny]

Forgot you didn't have a Trooper. The IAC is round and mounts to the Throttle body with 2 screws. The plug comes out of the end of it. There are 2 sensors on the throttle body, one is the throttle position sensor which is right off the end of the shaft that goes through the body. The other (IAC) is off to the side of this and is to bypass air from one side of the butterfly valve in the throttle body to the otherside. Thus is adjust air intake automatically to maintain a constant Idle RPM I don't know if yours has one but the Trooper does. I suspect yours has too. Just type in Joyner forums into Google and you should find other forums. One forum is riding Arizona. I don't use this forum because there is sort of a lot of immature people using it and focus on bashing others machines. This of course keeps the forum from being as productive as it could be. There are some good people on that forum however with knowledge.

Lenny

[brostar]

Your ECU is behind the passengers seat horizontally on the sheet metal panel.

Cheers Mike.

[Guest Lenny]

Did you try adjusting the idle screw out? you keep mentioning its backed off all the way.As lenny mentioned ECU reads position of sensor,if not reading any it may be compensating.Hope someone else chimes in regarding my thoughts because that is what i was told by tech at joyner.

Good point ricksrb, maybe loosen the throttle position sensor and rotate it one way or the other and see if it does anything. Keep in mind that a lot of auto computers, and this is an automotive computer, will hold the engine at a higher rev until its warmed up. This is done through the IAC. but it does refrence the Throttle position sensor.

Lenny

[Chalkstk]

Did you try adjusting the idle screw out? you keep mentioning its backed off all the way.As lenny mentioned ECU reads position of sensor,if not reading any it may be compensating.Hope someone else chimes in regarding my thoughts because that is what i was told by tech at joyner.

Rick,

Throttle cam is at rest without idle srew even touching it. If I turn srew in, it high revs with just an 1/8th turn.

Frankie

[Chalkstk]

Your ECU is behind the passengers seat horizontally on the sheet metal panel.

Cheers Mike.

I must be missing it. The only box is the fuse panel which is on the passenger frame side. Mine is an 08. Could they have changed from other years? I did notice all my rubber hose slide on's were check cracked around outside, but not all the way thru, I siliconed them just in case. What ticks me off, is it runs so good and smooth when I get it to idle. And it never high revs going thru gears if I start off with normal idle. It will run till stopped, fine. Something about it sitting over nite. It is running right now. I'll fire it up in the AM and see it it idles. But first I'll turn the fuel pressure to 52 from 41.

Frankie

[Chalkstk]

Good point ricksrb, maybe loosen the throttle position sensor and rotate it one way or the other and see if it does anything. Keep in mind that a lot of auto computers, and this is an automotive computer, will hold the engine at a higher rev until its warmed up. This is done through the IAC. but it does refrence the Throttle position sensor.

Lenny

Lenny,

Where is this throttle position sensor? Is it the cam with the throttle cable riding on it?

Frankie

[ricksrb]

Rick,

Throttle cam is at rest without idle srew even touching it. If I turn srew in, it high revs with just an 1/8th turn.

Frankie

Exact point i am trying to make.ECU is getting signal from sensor that it is 0 position thus compinsates but giving more throtle.Try to adjust up and let ECU recalibrate to new position of throttle.It may or may not work but your idle screw should not be backed off like that.Again I am by far no expert but this i have been told by reliable source and i am sure other here would agree that there may be some thing wrong just because the screw is backed off like that.Again it may not solve your rev problem but something is not right because that screw is backed off.Read closly again Lennys last post.

[Kinarfi]

Lenny,

Where is this throttle position sensor? Is it the cam with the throttle cable riding on it?

Frankie

The throttle position sensor is on the the opposite side from the cam that the throttle cable is on, it is spring loaded so that it follows the throttle position, if it had a more powerful spring, you would not need the throttle return spring, but it is to small and that is not it's purpose. I is just a potentiometer and if you hook an ohm meter to it, and operate the throttle, you will see the resistance change.

[Chalkstk]

Exact point i am trying to make.ECU is getting signal from sensor that it is 0 position thus compinsates but giving more throtle.Try to adjust up and let ECU recalibrate to new position of throttle.It may or may not work but your idle screw should not be backed off like that.Again I am by far no expert but this i have been told by reliable source and i am sure other here would agree that there may be some thing wrong just because the screw is backed off like that.Again it may not solve your rev problem but something is not right because that screw is backed off.Read closly again Lennys last post.

You guys have a real passion and I can't tell you how much I appreaciate everyone trying solve this delema. I will srew the scew in till it just touches the cam and then a smigit more till it high revs and then back again? Of course I'll have to have in idle mode first after a bunch of start/stops.

Frankie

[Chalkstk]

The throttle position sensor is on the the opposite side from the cam that the throttle cable is on, it is spring loaded so that it follows the throttle position, if it had a more powerful spring, you would not need the throttle return spring, but it is to small and that is not it's purpose. I is just a potentiometer and if you hook an ohm meter to it, and operate the throttle, you will see the resistance change.

So what did Lenny mean by changing it's position back nd forth? Mechanically I assume?

Do you think that when I finally get it to idle after start/stop that the engine is warming up some and then finally idles? If so, what does that tell us? Anything different than we know up to now? Remember guys I'm a novice but I can turn a wrench if I know what to turn.

Bless you all,

Frankie

[Guest Lenny]

So what did Lenny mean by changing it's position back nd forth? Mechanically I assume?

Do you think that when I finally get it to idle after start/stop that the engine is warming up some and then finally idles? If so, what does that tell us? Anything different than we know up to now? Remember guys I'm a novice but I can turn a wrench if I know what to turn.

Bless you all,

Frankie

The throttle position sensor will have a bit of play where the 2 screws hold it on. Loosen them and rotate the entire sensor, body and all, one direction and while holding it there, tighten the screws. Then try it the other direction and see if there is any differance in its running.

Lenny

[Chalkstk]

The throttle position sensor will have a bit of play where the 2 screws hold it on. Loosen them and rotate the entire sensor, body and all, one direction and while holding it there, tighten the screws. Then try it the other direction and see if there is any differance in its running.

Lenny

Did everything you and Rick offered. Ran fine twice start and stop. Had a cup of coffee, went back out and high revved again. I give up. Hopefully Joyner will have dealers again, and I'll bring it in. Still can't find ECU in engine compartment. It must be under cowl in front?

Disappointed, but beyond anger

Frankie

[ricksrb]

Frankie,

Dont know if you have spoke to Casey(was shop foreman at joyner) regarding your problem but if not give him a call.I saw him this past weekend and purchased some parts from him and said he was available to help anytime (480)766 6137

[Chalkstk]

Frankie,

Dont know if you have spoke to Casey(was shop foreman at joyner) regarding your problem but if not give him a call.I saw him this past weekend and purchased some parts from him and said he was available to help anytime (480)766 6137

Rick,

Can you give me a list of all sensors on the R-2, 3 banger? Then I'll call him and see which or all he has available. It seems at this juncture, that one or more of these sensors is defective. I stil have not found the CPU and I pray this big buck part is sound.

Thx,

Frankie

[ricksrb]

Rick,

Can you give me a list of all sensors on the R-2, 3 banger? Then I'll call him and see which or all he has available. It seems at this juncture, that one or more of these sensors is defective. I stil have not found the CPU and I pray this big buck part is sound.

Thx,

Frankie

Im a trooper person,couldnt tell you how many.I was suggesting you call him to ask what he might think your problem is,not sure if he had much in the way of sensors for sale.

[Chalkstk]

Im a trooper person,couldnt tell you how many.I was suggesting you call him to ask what he might think your problem is,not sure if he had much in the way of sensors for sale.

Rick,

Maybe you missed it, but I had the machine in Tempe for this prob and all Casey did was replace battery. Then he sent me a MAS sensor. Then Joyner went kaput. So he did not know either. Remember, this has been going on since Aug of 08.

There is only 800 miles on the R-2 which shows how much I haven't enjoyed driving it. He was warantee'ing it but now I have to pay for whatever. I just wish I knew what to buy and then find out if anybody has the right part or parts.

If it's the computer, I'll plant flowers in it. I hid my sledge hammer:)

Frankie

[brostar]

Chalkstk, look in page 159 of your Renegades owners manual. Part # 2 shows a photo of your ECU & that shows it is wide but flat so is easy to miss. On page 228, part #49 is the plastic cover. It should be bolted standing up-right by your passengers seat support normally behind. It is possible yours might be in a different area. Could be under the seat inside the storage. If it's in the front it should be near the battery in a well protected area but not likely. The Renegades have a really good rear inner mud guard that the Troopers don't have so forward of that is the best place to put the ECU.

To find out what sensors you have and what they look like, starting from page 105 in your manual is a complete break down of you EFI system and troubleshooting paragraphs for you. Work your way through this without doing all the tests to quickly get you into the area you need to concentrate on and then to the tests.

Cheers Mike.

[ricksrb]

Rick,

Maybe you missed it, but I had the machine in Tempe for this prob and all Casey did was replace battery. Then he sent me a MAS sensor. Then Joyner went kaput. So he did not know either. Remember, this has been going on since Aug of 08.

There is only 800 miles on the R-2 which shows how much I haven't enjoyed driving it. He was warantee'ing it but now I have to pay for whatever. I just wish I knew what to buy and then find out if anybody has the right part or parts.

If it's the computer, I'll plant flowers in it. I hid my sledge hammer:)

Frankie

sorry i did miss that.

[Guest Lenny]

Well, maybe I can come up with an answer. I'm going to just think out loud here while trying to logically understand what is happening. Now that I have mine running, it is doing sort of the same thing, reving. I had the problem before but it didn't only happen when cold. On mine, the throttle body is up high where I can get at it easily to adjust the idle screw. That makes it easy to play around with some ideas. Mine wants to idle at 500 RPMs when I start it. The computer should be pushing that up to 900, which is the default factory setting in the computer, by opening the IAC but it doesn't. When I adjust the idle screw up,the idle controllably climbs like it should but sometimes when it hits 900-1000 rpms, it starts to rev to maybe 3000. I have to shut it off and restart it, then i'm back to 500. Before when I had the problem, I just eliminated the IAC. Keep in mind that if the IAC is open when you unplug it, it will still rev. I actually pulled the IAC and plugged off the port. This worked. I ran this way for a long time and saw no ill effects regained control of my idle rpms. There is only one way the engine can rev higher. That is to get more air. If you have a manifold leak, it will want to rev. If the leak is closing up when things heat up it will idle down. Another way is for the IAC to open. In order for it to open, it needs current from the computer or I suspose if you had a intermitant short giving it current that could do it too. The IAC sends nothing back to the computer, it is simply a slave devise that is susposed to obay computer commands. By disconnecting it you just stop it from excuting a command. The computer doesn't know it's not there it just sees a need for more rpms and keeps sending current to the IAC to rev the engine and waits for the RPM sensor to report the desired rpms have been reached at which time the computer would stop sending current to the IAC. The computer can send current to the IAC to either retract (open) it or close it depending on what is needed for rpms. The final way is to turn the idle screw in farther. On my Trooper I'm going to first just eliminate the IAC like I did before and I suspect that I will now have control over the idle using the idle screw. For my use this works fine. On a car with air conditioning for example, when the air is turned on it wants to pull down the rpms but the computer sees this and immediately opens the IAC to compensate for the extra pull on the engine so the car keeps idling at the same RPMS. On my Dodge diesel 6 spd stick, I can put it in say 3 gear at take off and not push on the throttle pedal. The truck once it gets moving wants to scoot ahead and gain some speed. It accelerates until the engine is holding its minimun idle rpms. This is also the IAC responding to the computer. The only other thing that I can think of that gives the computer information causing it to ask for more rpms is the RPM sensor which should be some where on the bell housing and reading probably off the flywheel. If this sensor had a poor connection or was defective, the computer could be seeing an inaccurate reading of rpms and responding accordingly. Other then that, I can't think of any other sensor that gives the computer information that makes it want to change the rpms. That said, then is has to be a leak, bad IAC, bad RPM sensor, bad cinnection, short or a bad commputer. Wow, I'm out of wind.

Lenny

[ricksrb]

Well, maybe I can come up with an answer. I'm going to just think out loud here while trying to logically understand what is happening. Now that I have mine running, it is doing sort of the same thing, reving. I had the problem before but it didn't only happen when cold. On mine, the throttle body is up high where I can get at it easily to adjust the idle screw. That makes it easy to play around with some ideas. Mine wants to idle at 500 RPMs when I start it. The computer should be pushing that up to 900, which is the default factory setting in the computer, by opening the IAC but it doesn't. When I adjust the idle screw up,the idle controllably climbs like it should but sometimes when it hits 900-1000 rpms, it starts to rev to maybe 3000. I have to shut it off and restart it, then i'm back to 500. Before when I had the problem, I just eliminated the IAC. Keep in mind that if the IAC is open when you unplug it, it will still rev. I actually pulled the IAC and plugged off the port. This worked. I ran this way for a long time and saw no ill effects regained control of my idle rpms. There is only one way the engine can rev higher. That is to get more air. If you have a manifold leak, it will want to rev. If the leak is closing up when things heat up it will idle down. Another way is for the IAC to open. In order for it to open, it needs current from the computer or I suspose if you had a intermitant short giving it current that could do it too. The IAC sends nothing back to the computer, it is simply a slave devise that is susposed to obay computer commands. By disconnecting it you just stop it from excuting a command. The computer doesn't know it's not there it just sees a need for more rpms and keeps sending current to the IAC to rev the engine and waits for the RPM sensor to report the desired rpms have been reached at which time the computer would stop sending current to the IAC. The computer can send current to the IAC to either retract (open) it or close it depending on what is needed for rpms. The final way is to turn the idle screw in farther. On my Trooper I'm going to first just eliminate the IAC like I did before and I suspect that I will now have control over the idle using the idle screw. For my use this works fine. On a car with air conditioning for example, when the air is turned on it wants to pull down the rpms but the computer sees this and immediately opens the IAC to compensate for the extra pull on the engine so the car keeps idling at the same RPMS. On my Dodge diesel 6 spd stick, I can put it in say 3 gear at take off and not push on the throttle pedal. The truck once it gets moving wants to scoot ahead and gain some speed. It accelerates until the engine is holding its minimun idle rpms. This is also the IAC responding to the computer. The only other thing that I can think of that gives the computer information causing it to ask for more rpms is the RPM sensor which should be some where on the bell housing and reading probably off the flywheel. If this sensor had a poor connection or was defective, the computer could be seeing an inaccurate reading of rpms and responding accordingly. Other then that, I can't think of any other sensor that gives the computer information that makes it want to change the rpms. That said, then is has to be a leak, bad IAC, bad RPM sensor, bad cinnection, short or a bad commputer. Wow, I'm out of wind.

Lenny

Lenny,

I was out of wind just reading it..This would be good to put in a trouble shooting topic.That was great.Thank you.

[Kinarfi]

Hope I'm not off subject, but I've seen IAC in a few places in this thread, but I can't find it in my manual, so what is it, which page is it on in the 1100trooperT2-T4_owners_manual, please.

Thanks

Kinarfi

[Chalkstk]

Well, maybe I can come up with an answer. I'm going to just think out loud here while trying to logically understand what is happening. Now that I have mine running, it is doing sort of the same thing, reving. I had the problem before but it didn't only happen when cold. On mine, the throttle body is up high where I can get at it easily to adjust the idle screw. That makes it easy to play around with some ideas. Mine wants to idle at 500 RPMs when I start it. The computer should be pushing that up to 900, which is the default factory setting in the computer, by opening the IAC but it doesn't. When I adjust the idle screw up,the idle controllably climbs like it should but sometimes when it hits 900-1000 rpms, it starts to rev to maybe 3000. I have to shut it off and restart it, then i'm back to 500. Before when I had the problem, I just eliminated the IAC. Keep in mind that if the IAC is open when you unplug it, it will still rev. I actually pulled the IAC and plugged off the port. This worked. I ran this way for a long time and saw no ill effects regained control of my idle rpms. There is only one way the engine can rev higher. That is to get more air. If you have a manifold leak, it will want to rev. If the leak is closing up when things heat up it will idle down. Another way is for the IAC to open. In order for it to open, it needs current from the computer or I suspose if you had a intermitant short giving it current that could do it too. The IAC sends nothing back to the computer, it is simply a slave devise that is susposed to obay computer commands. By disconnecting it you just stop it from excuting a command. The computer doesn't know it's not there it just sees a need for more rpms and keeps sending current to the IAC to rev the engine and waits for the RPM sensor to report the desired rpms have been reached at which time the computer would stop sending current to the IAC. The computer can send current to the IAC to either retract (open) it or close it depending on what is needed for rpms. The final way is to turn the idle screw in farther. On my Trooper I'm going to first just eliminate the IAC like I did before and I suspect that I will now have control over the idle using the idle screw. For my use this works fine. On a car with air conditioning for example, when the air is turned on it wants to pull down the rpms but the computer sees this and immediately opens the IAC to compensate for the extra pull on the engine so the car keeps idling at the same RPMS. On my Dodge diesel 6 spd stick, I can put it in say 3 gear at take off and not push on the throttle pedal. The truck once it gets moving wants to scoot ahead and gain some speed. It accelerates until the engine is holding its minimun idle rpms. This is also the IAC responding to the computer. The only other thing that I can think of that gives the computer information causing it to ask for more rpms is the RPM sensor which should be some where on the bell housing and reading probably off the flywheel. If this sensor had a poor connection or was defective, the computer could be seeing an inaccurate reading of rpms and responding accordingly. Other then that, I can't think of any other sensor that gives the computer information that makes it want to change the rpms. That said, then is has to be a leak, bad IAC, bad RPM sensor, bad cinnection, short or a bad commputer. Wow, I'm out of wind.

Lenny

Lenny,

I appreciate your knowledge, but remember I do not even know what the IAC is or where it is. I need pics of my motor and arrows pointing to these varied sensors you speak of. But the manual is no help. When my motor idles, it is only about 650, not 900. If I turn the screw in, it over revs and not just upping the idle speed a little at a time. I did the throttle sensor twist and tighten thing and it id nothing,

If I had parts to interchange, I could manage. One or more must be defective. But you have me worried about intake manifold leak. I'm assuming you mean intake and not exhaust, correct? Early on when problem first began, Casey told me to run engine and spray starting fluid on intake. He said if motor rpm's increase, then there was a leak. It didn't do it at the time. Should i try this again?

There is one sensor above the throtle sensor. Looks like a bullet when removed. What does it do and what is it called? I did change the MAS sensor Casey sent me awhile back just before they went out. No change. So it's a real crapshoot.

Thx,

Frankie

[Guest Lenny]

Lenny,

I appreciate your knowledge, but remember I do not even know what the IAC is or where it is. I need pics of my motor and arrows pointing to these varied sensors you speak of. But the manual is no help. When my motor idles, it is only about 650, not 900. If I turn the screw in, it over revs and not just upping the idle speed a little at a time. I did the throttle sensor twist and tighten thing and it id nothing,

If I had parts to interchange, I could manage. One or more must be defective. But you have me worried about intake manifold leak. I'm assuming you mean intake and not exhaust, correct? Early on when problem first began, Casey told me to run engine and spray starting fluid on intake. He said if motor rpm's increase, then there was a leak. It didn't do it at the time. Should i try this again?

There is one sensor above the throtle sensor. Looks like a bullet when removed. What does it do and what is it called? I did change the MAS sensor Casey sent me awhile back just before they went out. No change. So it's a real crapshoot.

Thx,

Frankie

The IAC is the "idle air controller". It's round, about 1-1/4" dia and about 1-1/2" long with a plug on the end facing to the side and it's mounted on the throttle body. There is an air port that goes from one side of the butterfly valve in the throttle body to the other side. This port allows air to bypass the butterfly valve so even if the throttle is fully closed, air can get to the engine to allow it to properly idle dispite the closed butterfly. The IAC interupts this port and can either open it so air flows or close it so no air flows through the port. When the IAC is removed, the plunger on the end that sticks into the port looks like a bullet about 3/8" dia. by about 3/4" long. Length varies depending on where the IAC is at. This bullet shaped plunger moves in and out, opening or closing the air bypass port. The IAC has a small electric stepper motor in it that turns a threaded sleeve which causes the plunger to move either way. Read my long post above to see why there is an IAC on an engine. See page 120 of the T2 owners manual. Also page 143 shows a picture of the throttle body #2 and on its upper right corner is the IAC.

Chalkstk, intake and not exhaust, is correct. I don't think is is a manifold leak but possible. I'll report back after i get my reving problem stopped.

Lenny

[Chalkstk]

The IAC is the "idle air controller". It's round, about 1-1/4" dia and about 1-1/2" long with a plug on the end facing to the side and it's mounted on the throttle body. There is an air port that goes from one side of the butterfly valve in the throttle body to the other side. This port allows air to bypass the butterfly valve so even if the throttle is fully closed, air can get to the engine to allow it to properly idle dispite the closed butterfly. The IAC interupts this port and can either open it so air flows or close it so no air flows through the port. When the IAC is removed, the plunger on the end that sticks into the port looks like a bullet about 3/8" dia. by about 3/4" long. Length varies depending on where the IAC is at. This bullet shaped plunger moves in and out, opening or closing the air bypass port. The IAC has a small electric stepper motor in it that turns a threaded sleeve which causes the plunger to move either way. Read my long post above to see why there is an IAC on an engine. See page 120 of the T2 owners manual. Also page 143 shows a picture of the throttle body #2 and on its upper right corner is the IAC.

Chalkstk, intake and not exhaust, is correct. I don't think is is a manifold leak but possible. I'll report back after i get my reving problem stopped.

Lenny

Yes, that is the bullet shaped sensor I removed. But I can't get it physically to move. I sprayed it with contact cleaner and reinstalled. If I remove it from port and hit ignition, should it move or engage? Also I have the R-2 manual. The page numbers are probably different from the T-2. Should I just look under electrical heading?

Frankie

[Guest Lenny]

Yes, that is the bullet shaped sensor I removed. But I can't get it physically to move. I sprayed it with contact cleaner and reinstalled. If I remove it from port and hit ignition, should it move or engage? Also I have the R-2 manual. The page numbers are probably different from the T-2. Should I just look under electrical heading?

Frankie

You can't move it by hand easily and you don't want to force it. Yes, it should move if you remove and while plugged in, you turn on the ignition. If it's already all the way out it probably won't.

Lenny

[Chalkstk]

You can't move it by hand easily and you don't want to force it. Yes, it should move if you remove and while plugged in, you turn on the ignition. If it's already all the way out it probably won't.

Lenny

Yes it is all the way out. The only thing I did yesterday was to remove and contact spray both the IAC and the throttle sensor. Today, it started fine and ran all day without one high rev cycle. Tomorrow I'll try again. Would be great if it was that simple, but not countng chickens yet

Frankie