Irractic Idle - Cleaning Throttle Body - 986 Forum

aussieboxy · 08-18-2007, 12:03 AM

From what I can tell this is a common problem with our cars & is very easily rectified.

With my 2000 2.7 the idle would vary from anywhere between 300 & 1300 and putting on the aircon made little difference.

I found out about this fix from a Rentech forum which was very useful.

Below is a brief runthrough on how to clean the throttle body.

1. Place the car into service mode with engine hatch open. You can clearly see the throttle body as marked in the pic

aussieboxy · 08-18-2007, 12:10 AM

2. Remove the black induction tube by lossening the hose clamp at the throttle body end and then the other clamp at the other end which connect to the airbox wher the air filter is located.

I found it easier to just reome the tube rather than just the end near the throttle body.

3. Next remove the 4 bolts holding the trottle body to the intact. They have an allen head.

aussieboxy · 08-18-2007, 12:24 AM

4. Remove throttle body & place on top of engine. I put a old towel underneath it to catch the excess cleaning fluid.

5. Clean the trottle body(both sides) with carb cleaner. The pics are mine before cleaning.

aussieboxy · 08-18-2007, 12:33 AM

5. Replace the trottle body with the 4 hex bolts. Careful not to overtorque as they are into a metal sleve in plastic. Just hand tight then nip them up.

6. Replace intake tube. It can be a little difficult to get the end back on the throttle body so I used just a little WD 40 or CRC on the inside lip to help it slip back on.

7. Tighten both end clamps of intake tube & start her up.

8. Replace engine cover & return hood to normal position & your done.

Quite easy to do and should only take you about an hour or so from do to wow.

If you have any questions PM me.

Good luck.

SC986 · 08-18-2007, 10:25 AM

Good work and thanks for the write up and pics. I've got to do this, having the same idle issues.

davej_anderson · 08-22-2007, 09:00 AM

Great right up!
I'll be doing this this weekend.

2 quick questions:
1) did you dry the throttle body after cleaning it or did you let the cleaner evaporate dry?
2) when cleaning it with the fluid, did you just let the fluid run over the surfaces or did you scrub the surfaces with a brush/cloth?

aussieboxy · 08-25-2007, 02:11 AM

1) Yes I cleaned it with a cloth after I sprayed the cleaner in the throttle body. Did this several times until completeely clean.

2) Yes rubbed it with a clean cloth. Not much effort just a few sprays and wiping.

Quote:

Originally Posted by davej_anderson

Great right up!
I'll be doing this this weekend.

2 quick questions:
1) did you dry the throttle body after cleaning it or did you let the cleaner evaporate dry?
2) when cleaning it with the fluid, did you just let the fluid run over the surfaces or did you scrub the surfaces with a brush/cloth?

davej_anderson · 08-25-2007, 02:53 AM

thanks! i'll hopefully be doing this this afternoon

aussieboxy · 09-05-2007, 06:35 PM

I have noticed since cleaning the throttle body that at start up the car initially revs to about 2.5K before dropping down to the aoto choke type level og about 1.1K

Has anyone else found this?

davej_anderson · 09-06-2007, 01:28 AM

Quote:

Originally Posted by aussieboxy

I have noticed since cleaning the throttle body that at start up the car initially revs to about 2.5K before dropping down to the aoto choke type level og about 1.1K

Has anyone else found this?

Can't say I've noticed but then again I haven't looked to see what level it revs to on the first turnover of the engine. Mine sits at about 1k rpm until its warmer and then settles down to about 650 rpm

tboyer · 12-16-2007, 05:00 PM

The only thing I would like to add is when re-attaching the tube to the throttle body, use a bar of soap on the inside of the tube and on the outside of the thottle body itself. This offers just enough to slip the tube back over. Without it, you'll spend a good 30 minutes pushing just to get nowhere fast.

I cleaned mine because at idle, my engine would chase between 900 and 750 RPMs. Now the car starts and idles at 1100 RPMS before falling AND STAYING steady at 850 RPMS. Here are some pics of the before and after cleaning.

ROMES · 01-27-2008, 12:54 AM

What did you use to clean the Throttle body ? thnx mine is having the same idle issues...heres to a quick fix! lol

tboyer · 01-27-2008, 03:38 AM

I used Gunk silicon spray (as shown in my picture) to clean the TB, afterwards and when warmed up, the car idles steady at 650 RPM

HOWEVER, when at idle, the car hesitates in almost a recycle state. RPMs stay steady at 650 RPMs, the car does not idle steady it jumps around similar to when you turn the A/C on, or use any other power source including the head lights. Any ideas?

derb · 01-27-2008, 06:52 AM

Maybe your idle air control valve also needs cleaning.

ROMES · 01-27-2008, 10:41 AM

It's pouring pretty bad in California otherwise i'd go out and by some cleaner and get going on this quick fixer lol...

Oh well i'll just redline it before i take off in first hahahah j/k

aussieboxy · 01-28-2008, 08:27 PM

Derb it depends on your madel. The 2.7 egas don't have an IACV (Idle Air Control Value) which is something I discovered when I couldn't find mine LOL.

derb · 01-29-2008, 04:38 AM

aussieboxy,
Thanks for clarifying that. I did not know that.
Regards,
mike

tboyer · 01-29-2008, 06:48 AM

Quote:

Originally Posted by aussieboxy

Derb it depends on your madel. The 2.7 egas don't have an IACV (Idle Air Control Value) which is something I discovered when I couldn't find mine LOL.

3.2 egas doesn't have a ICV either, I found a post by P51-Mustang on renntech that shows the MAF (which has been changed recently) could be the problem, going to play around this week and see if I have any improvement. I had these same CEL codes P1128 and P1130 while driving home from Missouri to Maryland a few months ago. Porsche stated could have been triggered by driving the car 1000+ miles in a short period of time. Since I got home and after 1,500+ miles, CEL has not returned (fingers crossed)

edevlin · 07-10-2008, 07:13 AM

Great write-up on the how-to. I have been meaning to do this for the last year or so and finally got around to it today. Only took a little over a half hour for me to do the job and get the car back together, and boy, was that sucker dirty.

I was suprised because I regularly use injector cleaner in my fuel. There was a pretty thick buildup of material in the throttle body, especially on the lower side. Rags and carb cleaner did the trick to make it look like new. When I started the car after the cleaning, I noticed the idle was smoother right away.

I have 75K on my 2000 base boxster and based on what it was like getting the bolts off, I suspect this was the first time the throttle body was cleaned. Based on how dirty it was, one would think that cleaning the throttle body would be part of the regular 60K or 75k maintenance schedule for our cars....

Ed