Anytime I would disconnect the battery or clear the codes for any reason, the idle would get very jumpy, surging between 600-800. Over time it would mostly smooth out, but it would come back at times.
With e-gas, the butterfly valve is always slightly open for idle (there is no dedicated idle valve like with the cable throttle 97-99 boxsters) If it gets gunked up, enough air doesn't get through and so you have a low idle. The ECU opens up the valve a little, idle shoots up. ECU drops it back, and it goes back down but too low. Up and down, up and down. Over time I believe the ECU learns the right fraction to hold it open which minimizes this. I forget which setting on Durametric, but I could see the throttle percentage going up and down and up and down as the ECU tried to smooth out the idle.
Today I was in there and I decided to clean the throttle body. I have a 2000 S and my pictures looked different from Pedros guide and also the 101 Projects guide so here are some new pictures .I have e-gas, but also the AOS tube looked different on mine.
Before you start, some things to keep in mind:
Quote:
Originally Posted by nieuwhzn
Bit of advice. Do this at a pretty high ambient temperature otherwise the hoses are too stiff. Since you are in there consider cleaning the MAF too.
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Good points there, while you are in there it is a good time to:
- Check your air filter
- Clean your MAF
- Check your power steering fluid
My procedure was:
- Put the top in service position and remove the engine cover.
- Disconnect negative end of battery (just for safety)
- Loosen the screw clamp at the MAF end of the intake tube and slip the tube off (I tried to take just the other end off but the tube is too rigid)
- Loosen the screw clamp on the throttle body side of the intake tube and pop that sucker off. It was tough to get off.
- Remove the nut that is holding down the throttle body.
- Remove the AOS tube from the intake just after the throttle body. To do that you squeeze the plastic ring on the serrated parts and slide it off. Even after releasing the clip it still has to slide a decent little amount before it comes off.
- Loosen the screw clamps that are holding the bands that hold the intake splitter. These need to be loose so you can rotate the throttle body up. I did all 4 but I think you could do just the inner ones.
- Rotate the throttle body up, and unclip the e-gas connector. It is a squeeze tab to release but mine was very brittle and half of one tab end broke off, and the whole other tab broke off. I was worried it would not be secure when reinstalling but it was.
- Rotate the throttle body up some more and get ready to clean.
At this point I could have removed the whole throttle body but I decided to just clean in place as I did not have a gasket. If you do remove it, the gasket behind it is part number 99611031802, #9 in this diagram:
http://www.********************************************.com/porsche-parts/hardparts.php?dir=986-97-04§ion=107-10
The torque value for the 4 throttle body bolts is 9.7NM (7.0 ft/lbs)
It was gunked up pretty bad (and I lied, I do have a picture of the connector, here it is)
I hit it with some throttle body cleaner and wiped it down pretty good and got it nice and mostly shiny.
DO NOT USE THE STRAW THAT COMES WITH THE THROTTLE BODY CLEANER OR YOU *WILL* BLOW IT DOWN THROUGH AND PAST THE THROTTLE BODY. REPEAT: DO NOT. How do I know? Even after reading this exact guidance in another thread, I figured I would hold the straw with my finger and keep it tight. Guess what? When I had to use that hand to prop open the throttle body I blew the red straw down inside. Very luckily, it stopped just within reach of a long pair of needle nose pliers and I did not have to do more disassembly to get it...
Reinstallation is the reverse of assembly...
- Reattach the e-gas clip to the throttle body.
- Rotate the throttle body down
- I loosely fastened the nut holding down the throttle body to keep it from moving at this point and then attempted to refit the throttle body end of the intake tube... It is very hard to get leverage in there. After many attempts I sprayed the throttle body cleaner on the outside of the throttle body to clean it up and provide some lubrication, and then I was able to pop that tube on, and then tighten the screw clamp.
- Re-tighten the throttle but hold down nut all the way (I just realized I did not do that yet until I was typing these instructions)
- Tighten the screw clamps on the splitter that is downstream of the throttle body. Leaving these loose but with the nut on loosely gives you a little wiggle room on the throttle body as you try to get that tube on. Possibly it could be better to tighten them both up before fitting the tube.
- Re-attach the AOS tube. Make sure it clicks. It slides on a decent bit before it is fully engaged and clicks.
- Slip on the MAF end of the intake tube and tighten it up (way easier than the other end). Before you slip it on, rotate the screw clamp so that you can get to the screw as it may have rotated down.
- I let it sit for a little before tightening it all back to give as much of the throttle body cleaner time to evaporate.
- Reconnect the battery. Turn the key on but let it sit for a minute and do not touch the gas pedal. This is to allow time for the ECU to perform throttle adaptation. I have heard that if you do not do this the idle might be messed up or at the wrong RPM.
- Crank it up. In my case it took about 30 seconds of cranking, a short pause, and then about 10 seconds of cranking before it started up. Probably because of the throttle body cleaner getting down in there.
Idle... rock steady!
Time, 1.5 hours (considering I already had most of the engine compartment open) and I would be able to go a lot faster next time, probably less than an hour.
This was the first time that I unclipped the fasteners at the bottom of the clamshell and moved it up higher out of the way. WAY more room, I will do it this way from now on. Those little clips are a hassle though, I think I have not figure out the right procedure for getting them off.
While I was in there I also installed the drain screens I got for Christmas. I keep the car garaged but these were an inexpensive Christmas gift to myself.
