Fluctuating Idle

[mik]

just found this thread while researching an erratic idle problem and it looks like it's time I cleaned the throttle body (2001 2.7 72k miles)

would a dirty TB also cause 'hesitation' under hard acceleration between 4 and 5000 rpm?

thanks guys :)

[1schoir]

just found this thread while researching an erratic idle problem and it looks like it's time I cleaned the throttle body (2001 2.7 72k miles)

would a dirty TB also cause 'hesitation' under hard acceleration between 4 and 5000 rpm?

thanks guys :)

mik:

Not sure about whether that can be caused by a dirty throttle body, but I can tell you from personal experience that a faulty MAF (Mass Air Flow Sensor) can cause EXACTLY what you are describing.

Regards, Maurice.

Edited September 2, 2008 by 1schoir

[rprieto]

Hi guys, I opened the engine again to take some pics and I tried to get the TB out once more.

In the picture below I loosened the hose clamp in blue, number 3 (the screw popped out and got lost in the open parking lot and I had to replace it with a generic, PepBoys clamp). Then I loosened the other hose clamp - number 2. After all this I could not move the tube a single inch from the TB, but the number 3 end came out easily. Should I just keep on pulling the end close to the TB or is there an easier way to do this? Can I cause any damage by pulling hard...

I also added a second picture just to show how dirty the Throttle is on the outside... I really need this cleaning.

Any help is appreciated.

I just cleaned the throttle body for the first time on my '01 2.7 this past weekend (yesterday - Sunday). Despite all the discussion on this in the past, I had trouble searching for the procedure for getting to the throttle body and removing it. Here's what I did:

Loosened the hose clamps on both ends of the plastic tube [1 in your first picture] running from just past the MAF / air filter box [3] to the throttle body [2]. As you noted, the end [3] that butts up to the MAF comes off pretty easily. The other end that joins the throttle body i[2] s a real pain to get off. I pulled, twisted and wiggled for about 30 minutes, and somehow just got the right combination of moves and it finally came off. My hands aren't that large, but my knuckles are pretty beat up. I found it's easiest to access from the driver's rear fender side. Don't worry about the trouble getting it off, because it's even harder to get back on!

I don't think it's possible to get the throttle body off without disconnecting the plastic tube at [2], but if there is, it would probably save half an hour or so. Same comment applies to reassembly.

I haven't read about anyone using a blow dryer to heat up the plastic tube at [2] to expand it to get it on and off easier. I was going to try that if all else failed after a few hours. Somehow, the plastic tube just came off after struggling for a while.

Once the black plastic tube is off, pull it out and set it aside. It was clean on the inside, but I wiped the outside down with several rounds of Simple Green, followed with water to get the Simple Green residue off. The throttle body comes off by unscrewing the 4 long bolts with a metric hex driver. The 2 long bolts on the driver's side have washers, and the 2 on the passenger side do not. Once you have the 4 bolts off, the throttle body is still connected with an electrical connector (e-Gas models), which simply unplugs. Pay attention to the orientation of everything. You'll notice on the throttle body there's an arrow that lines up with an arrow on the plastic air tube (visible in your second photo).

Cleaning the throttle body is the easy part. Just keep spraying throttle body cleaner and wiping the crud off. You can push the flap open to get all the way through - it's spring loaded so watch your fingers. I also tried wiping down the tubing on the back side of the throttle body, but it was pretty clean inside (at 51K miles).

The only hard part (as you would expect) is getting the plastic pipe [1] back onto the throttle body [2] after the throttle body is reattached. Expect another 30+ minutes of pushing, twisting, wiggling, swearing, etc. I lightly sprayed some silicon spray on a paper towel, then wiped it on the outside of the throttle body and inside of the plastic pipe. Hard to tell if it helped or not, but it didn't hurt. After everything is put back together, start you car and make sure everything runs and the throttle works before closing everything up.

When I was all done, I gently re-tightened all the hose clamps since several felt semi-loose

I don't think it matters how dirty the throttle body is on the outside for how your car runs! It's the inside that counts. But there's no reason not to clean up the outside when you have the throttle body out

Working this as I write this. Looks like it will help as I am stuck. Thanks.

[mogulmentor]

Hi guys, I opened the engine again to take some pics and I tried to get the TB out once more.

In the picture below I loosened the hose clamp in blue, number 3 (the screw popped out and got lost in the open parking lot and I had to replace it with a generic, PepBoys clamp). Then I loosened the other hose clamp - number 2. After all this I could not move the tube a single inch from the TB, but the number 3 end came out easily. Should I just keep on pulling the end close to the TB or is there an easier way to do this? Can I cause any damage by pulling hard...

I also added a second picture just to show how dirty the Throttle is on the outside... I really need this cleaning.

Any help is appreciated.

I just cleaned the throttle body for the first time on my '01 2.7 this past weekend (yesterday - Sunday). Despite all the discussion on this in the past, I had trouble searching for the procedure for getting to the throttle body and removing it. Here's what I did:

Loosened the hose clamps on both ends of the plastic tube [1 in your first picture] running from just past the MAF / air filter box [3] to the throttle body [2]. As you noted, the end [3] that butts up to the MAF comes off pretty easily. The other end that joins the throttle body i[2] s a real pain to get off. I pulled, twisted and wiggled for about 30 minutes, and somehow just got the right combination of moves and it finally came off. My hands aren't that large, but my knuckles are pretty beat up. I found it's easiest to access from the driver's rear fender side. Don't worry about the trouble getting it off, because it's even harder to get back on!

I don't think it's possible to get the throttle body off without disconnecting the plastic tube at [2], but if there is, it would probably save half an hour or so. Same comment applies to reassembly.

I haven't read about anyone using a blow dryer to heat up the plastic tube at [2] to expand it to get it on and off easier. I was going to try that if all else failed after a few hours. Somehow, the plastic tube just came off after struggling for a while.

Once the black plastic tube is off, pull it out and set it aside. It was clean on the inside, but I wiped the outside down with several rounds of Simple Green, followed with water to get the Simple Green residue off. The throttle body comes off by unscrewing the 4 long bolts with a metric hex driver. The 2 long bolts on the driver's side have washers, and the 2 on the passenger side do not. Once you have the 4 bolts off, the throttle body is still connected with an electrical connector (e-Gas models), which simply unplugs. Pay attention to the orientation of everything. You'll notice on the throttle body there's an arrow that lines up with an arrow on the plastic air tube (visible in your second photo).

Cleaning the throttle body is the easy part. Just keep spraying throttle body cleaner and wiping the crud off. You can push the flap open to get all the way through - it's spring loaded so watch your fingers. I also tried wiping down the tubing on the back side of the throttle body, but it was pretty clean inside (at 51K miles).

The only hard part (as you would expect) is getting the plastic pipe [1] back onto the throttle body [2] after the throttle body is reattached. Expect another 30+ minutes of pushing, twisting, wiggling, swearing, etc. I lightly sprayed some silicon spray on a paper towel, then wiped it on the outside of the throttle body and inside of the plastic pipe. Hard to tell if it helped or not, but it didn't hurt. After everything is put back together, start you car and make sure everything runs and the throttle works before closing everything up.

When I was all done, I gently re-tightened all the hose clamps since several felt semi-loose

I don't think it matters how dirty the throttle body is on the outside for how your car runs! It's the inside that counts. But there's no reason not to clean up the outside when you have the throttle body out

Three weeks ago my alarm went off for no reason, '00 Boxster 2.7L 67,000 miles. I walked outside unlocked the car and the alarm stopped. I heard an erratic clicking coming from the rear luggage compartment and opened the lid. It sounded as if the no. 7 relay (Start Lock) was clicking and felt that way as well when I ran my hand over it. I disconnected the battery to stop the clicks and then ordered a replacement relay, thinking that it had just gone bad. Several days later I received the new switch, put it in to replace the old, and started the car. As I was pulling out of the driveway I noticed that I was not getting any acceleration and the car was idling funny. The CEL started blinking so I turned the car around and parked it.

I began reading through the forums to diagnose my problem. I decided to try cleaning the throttle body, per geoff's instructions, to see if that would help the idle issue. Today I took off the throttle body cleaned it and replaced it, and what do you know, my idle is now rock steady. I did not put the engine cover back on as I was finishing up, hooked up the battery and began having the strange clicking again in the rear trunk. However, this time I noticed that along with the relays clicking I could hear the throttle body flap opening and closing. The car was off, and the keys were not in the ignition. What would cause this?

Special thanks to geoff for helping me fix my idle problems, but I'm at a loss for what to do with this electric problem (gremlin). Here's the symptoms: Inside the passenger compartment the car dings (same ding as when you put the keys in but it's erratic, no pattern to it, and the keys are not in the ignition), the flap on the throttle body can be heard opening and closing sporadically, and the relay unit in the rear trunk clicks like crazy. In addition, the alarm will go off after a while amid all this craziness. What I have noticed is that if I put the key in the ignition and turn it so that the electronics come on in the car, all of the symptoms stop. I went for a drive this afternoon and everything else seemed fine. It's just after turning off the car and walking away for a few minutes all of this other stuff starts. I've been pulling off the negative lead to the battery so as not to annoy the neighbors with the alarm, and hopefully not fry any electronics.

Any body got any ideas?

[1schoir]

Three weeks ago my alarm went off for no reason, '00 Boxster 2.7L 67,000 miles. I walked outside unlocked the car and the alarm stopped. I heard an erratic clicking coming from the rear luggage compartment and opened the lid. It sounded as if the no. 7 relay (Start Lock) was clicking and felt that way as well when I ran my hand over it. I disconnected the battery to stop the clicks and then ordered a replacement relay, thinking that it had just gone bad. Several days later I received the new switch, put it in to replace the old, and started the car. As I was pulling out of the driveway I noticed that I was not getting any acceleration and the car was idling funny. The CEL started blinking so I turned the car around and parked it.

I began reading through the forums to diagnose my problem. I decided to try cleaning the throttle body, per geoff's instructions, to see if that would help the idle issue. Today I took off the throttle body cleaned it and replaced it, and what do you know, my idle is now rock steady. I did not put the engine cover back on as I was finishing up, hooked up the battery and began having the strange clicking again in the rear trunk. However, this time I noticed that along with the relays clicking I could hear the throttle body flap opening and closing. The car was off, and the keys were not in the ignition. What would cause this?

Special thanks to geoff for helping me fix my idle problems, but I'm at a loss for what to do with this electric problem (gremlin). Here's the symptoms: Inside the passenger compartment the car dings (same ding as when you put the keys in but it's erratic, no pattern to it, and the keys are not in the ignition), the flap on the throttle body can be heard opening and closing sporadically, and the relay unit in the rear trunk clicks like crazy. In addition, the alarm will go off after a while amid all this craziness. What I have noticed is that if I put the key in the ignition and turn it so that the electronics come on in the car, all of the symptoms stop. I went for a drive this afternoon and everything else seemed fine. It's just after turning off the car and walking away for a few minutes all of this other stuff starts. I've been pulling off the negative lead to the battery so as not to annoy the neighbors with the alarm, and hopefully not fry any electronics.

Any body got any ideas?

One good possibility is the (electrical portion of the) iginition switch.

It's easy (and very cheap) to replace to eliminate as a possible cause.

This is an unusual set of symptoms, compared to the usual manifestations of a failed ignition switch (hard to pull key out, A/C blower stays on, etc...). However, the fact that your symptoms disappear when you turn the key to turn on the electronics in the car points to the ignition switch as being a possibility.

Regards, Maurice.

[mogulmentor]

Three weeks ago my alarm went off for no reason, '00 Boxster 2.7L 67,000 miles. I walked outside unlocked the car and the alarm stopped. I heard an erratic clicking coming from the rear luggage compartment and opened the lid. It sounded as if the no. 7 relay (Start Lock) was clicking and felt that way as well when I ran my hand over it. I disconnected the battery to stop the clicks and then ordered a replacement relay, thinking that it had just gone bad. Several days later I received the new switch, put it in to replace the old, and started the car. As I was pulling out of the driveway I noticed that I was not getting any acceleration and the car was idling funny. The CEL started blinking so I turned the car around and parked it.

I began reading through the forums to diagnose my problem. I decided to try cleaning the throttle body, per geoff's instructions, to see if that would help the idle issue. Today I took off the throttle body cleaned it and replaced it, and what do you know, my idle is now rock steady. I did not put the engine cover back on as I was finishing up, hooked up the battery and began having the strange clicking again in the rear trunk. However, this time I noticed that along with the relays clicking I could hear the throttle body flap opening and closing. The car was off, and the keys were not in the ignition. What would cause this?

Special thanks to geoff for helping me fix my idle problems, but I'm at a loss for what to do with this electric problem (gremlin). Here's the symptoms: Inside the passenger compartment the car dings (same ding as when you put the keys in but it's erratic, no pattern to it, and the keys are not in the ignition), the flap on the throttle body can be heard opening and closing sporadically, and the relay unit in the rear trunk clicks like crazy. In addition, the alarm will go off after a while amid all this craziness. What I have noticed is that if I put the key in the ignition and turn it so that the electronics come on in the car, all of the symptoms stop. I went for a drive this afternoon and everything else seemed fine. It's just after turning off the car and walking away for a few minutes all of this other stuff starts. I've been pulling off the negative lead to the battery so as not to annoy the neighbors with the alarm, and hopefully not fry any electronics.

Any body got any ideas?

One good possibility is the (electrical portion of the) iginition switch.

It's easy (and very cheap) to replace to eliminate as a possible cause.

This is an unusual set of symptoms, compared to the usual manifestations of a failed ignition switch (hard to pull key out, A/C blower stays on, etc...). However, the fact that your symptoms disappear when you turn the key to turn on the electronics in the car points to the ignition switch as being a possibility.

Regards, Maurice.

I think you may be right. I did not even think about the ignition switch, I had it replaced about three years ago when my key would not come out of the ignition.

I played with it a little more today and it only acts up when the key has not been turned to the run position. I did notice that along with all of the other symptoms I listed before, the lights on the dash and in the cab stay on, and the fuel gauge bounces up and down.

I will replace the ignition switch in a few days and update on what I find. Thanks for your help!

[1schoir]

I think you may be right. I did not even think about the ignition switch, I had it replaced about three years ago when my key would not come out of the ignition.

I played with it a little more today and it only acts up when the key has not been turned to the run position. I did notice that along with all of the other symptoms I listed before, the lights on the dash and in the cab stay on, and the fuel gauge bounces up and down.

I will replace the ignition switch in a few days and update on what I find. Thanks for your help!

Definitely keep us posted.

Regards, Maurice.

[mogulmentor]

I think you may be right. I did not even think about the ignition switch, I had it replaced about three years ago when my key would not come out of the ignition.

I played with it a little more today and it only acts up when the key has not been turned to the run position. I did notice that along with all of the other symptoms I listed before, the lights on the dash and in the cab stay on, and the fuel gauge bounces up and down.

I will replace the ignition switch in a few days and update on what I find. Thanks for your help!

Definitely keep us posted.

Regards, Maurice.

Apparently when I had the ignition switch problem years ago and took it into the dealer they replaced the whole ignition assembly so I ended up ordering the original ignition switch which was the wrong switch for my car. After realizing this I ordered the other switch and was finally able to put it in two days ago. It seems that this did solve my electrical issues. Replacing the switch was pretty easy minus the little screws.

So for those out there with crazy electrical symptoms, it could be your ignition switch. My symptoms: alarm going off for no reason, random clicking in the relay panel in rear luggage compartment, throttle body opening/closing when the car was off, dash electronics staying on, sporadic dings inside the car (like when the key is in the ignition but the car is not turned on). All this was fixed for $35 (switch and shipping) plus $6 for a small screwdriver (bought at drugstore).

I started the car and it is running, but it shakes and coughs like crazy. Did not do this prior to initial electric problems. I have had the battery unplugged for the last month or so. I cleaned the throttle body about a month ago and it seemed to fix this issue for the day but now my idle problems are back. I also am not getting much if any response when I step on the gas. I've seen postings about the mass air flow sensor (could this be my problem?), or is it something else?

I'm afraid to let the car run to long or to take it out for a spin.

Edited January 1, 2009 by mogulmentor

[1schoir]

....

I started the car and it is running, but it shakes and coughs like crazy. Did not do this prior to initial electric problems. I have had the battery unplugged for the last month or so. I cleaned the throttle body about a month ago and it seemed to fix this issue for the day but now my idle problems are back. I also am not getting much if any response when I step on the gas. I've seen postings about the mass air flow sensor (could this be my problem?), or is it something else?

I'm afraid to let the car run to long or to take it out for a spin.

I don't think it's the MAF as the MAF has no effect on the idle.

Is it possible that since you had the battery disconnected that the computer just has to re-learn its settings?

Go back to the very top of this thread and re-read the posts there regarding fluctuating idle, etc. You may find your answer there.

Regards, Maurice.

[Brad Roberts]

This is a great thread :)

I'm a little concerned with people suggesting Techron in the gas as a way to combat the throttle body problem (the throttle body only flows AIR.. not GAS) so Techron in the gas would only help the injectors and cylinders :)

B

[00boxster]

Very helpful thread, was not gonna give the TB a clean as it appeared too hard opened my engine up last weekend and just ended up giving the engine a good clean after attempting to get at the TB. Mine had alot of oil on the outside of the oil filler tube and the 2nd bellows tube (the one on the opposite side to the TB).

Most the DIY info I found is on the non egas models, good to see some pix and a great description for removing the large intake tube for egas boxsters . . . think I will be having a crack at this again before my new MAF and air filter get here :D Does anyone know if you can use CRC CO cleaner on the TB?

:renntech:

[akboxster]

I had the same problem. I cleaned the throttle body as it had some black gunk anround the inside throat. I used some spray cleaner, cloth rags, old tooth brush and a que tip. Runs much better now.

I always use Chevron with Techron Supreme gas. If I use other station's gas I know the change. I also use the higher revs to keeps carbon build up down, these are high reving engines. I live in Anchorage Alaska where the environment is much different than the Lower 48 States.

The car does awesome, took it on a 700 mile road trip from Anchorage to Tok Alaska one a Sunday and then three days later from Anchorage to Fairbanks Alaska, about 800 mile round trip. Chevron available along the way.

[babeins]

OK, so I took my TB apart to clean this morning. when reassembling I broke this Y fitting for the air lines between what I think goes between the supply of the TB and the intake manifolds right above the heads maybe? The air lines are pretty old and tough. Any ideas as to how to get these air lines apart and replace this part? I've also posted a request for the part on the other forum. Thanks all.

[marco angelo]

just cleaned my TB it took just 30 minutes to clean. left my TB on the car and sprayed it inside with brakecleaner.

my tachometer stays steady now and car runs perfect!

[a.renshall]

I have 98 2.5 Boxster and have just changed the engine for a low mileage second hand unit (same year). I have a similar issue with the idle speed only in my case the car idles at 1200rpm when I understand it should be about 900rpm. It is steady however. Can anyone tell me is the idle speed self setting or is there a manual adjustment? If there is an ajuster where is it?

Alan

Liverpool

England

[gandrade1]

Hi guys...

Going for the second cleaning, but the link to the Tutorial (first post) no longer seems to work. Has the DIY been moved?

I saw one for the 996, but it is a bit different.

All the best,

Gus

[Loren]

Hi guys...

Going for the second cleaning, but the link to the Tutorial (first post) no longer seems to work. Has the DIY been moved?

I saw one for the 996, but it is a bit different.

All the best,

Gus

Apparently - still lots of good tips in the first 3 pages of this thread.