Idling fine - but lower than expected
 

Hi all,

I've been playing with the idle in my car after installing the Steve Wong Chip. According to the instructions, I should set my idle to 880. So after some help from people on the forums, I've done that. The problem is that no matter what I do, when I remove the jumper, the idle drops to just below the last hashmark, which, to me is 780, assuming: each 1000 RPM has 4 hashes in between EXCEPT For the first, which has 3, each hash is worth 200 RPM.

- Am I reading the tach right? When I set the idle, I aim for putting the needle somewhere between the last hash mark and the 1k on the tach.

- The idle is rock-solid and the car isn't struggling or stuttering, so I'm totally fine with it, I'm just worried that if the DME is working to lower from where I set it, to the 780, I'm overworking the DME.

- The tach may not be correct?

The car may be running a little rich, so I'm not sure if that impacts the idle.

Best,
Martin

are you jumping the correct pin/connector.
does the ICV work properly
is the throttle switch adjusted properly
is it closing when at idle

why do you think you are rich- could be the throttle sw.



http://forums.pelicanparts.com/porsche-911-technical-forum/829141-3-2-carrera-throttle-body-stop-adjustment.html

long story
 

Long story, but I've been going back and forth with DRACO who has been a great help, but since he's off to a wedding I figured I'd avoid pestering him with my silly questions. Bottom line is after replacing the stock chip with SW chip, when the car was hot, I'd occasionally get a bounce in the idle, from 1200 - 1500 or 1800 then back down. When I adjust my idle, I've been jumpering the 1 o'clock and 6 o'clock holes, I think that's B and C? My test port is slightly turned, so it's more like 1:30 and 6:30.

I've done the following:

- Jumpered test port and set idle to 880ish. So far, I haven't had the idle bounce again. Though, as I mentioned, I adjust to around 880 and when I remove jumper it takes the idle to slightly below 800.
- ICV working properly? No idea, it seems to.
- Idle switch is clicking when I move the throttle, so it seems OK.
- When I jumpered the test port, I was getting a whitish smoke from the car. That happened the first few times I adjusted, now it isn't happening any more.
- Draco suggested it might be running rich so I am working on a way to test that, in the meantime, I pulled my plugs and they were blackish and also iridium, so I replaced with copper.
- Black plugs suggest rich environment.

The car came from california and i believe colorado, I'm in florida now and run 93 octane. The plug in the AFR mixture setting is no longer there so someone probably fiddled with it at some point, both cali and colorado have higher elevations and lower octane, so maybe someone richened up the mix?

absolutely open to pointers or advice.

http://forums.pelicanparts.com/uploa...1466099902.jpg

you are not "overworking the DME"

what heat range are the plugs. you may want a heat range hotter. check plugs after a drive in the mid RPM's or after a hard pull, no idle. if plugs are fine at cruise but black at idle you just risk fouling a plug with long idles. could make it hard to start. I have run cold plugs on purpose that were blacker than yours and never had problems on a CIS car. (W3)

test the sw with a MM, preferably at the connector going to the DME.
condition of 02 sensor? try disconnecting it to see what idle does. (curious)
measure 02 sensor voltage to check mixture/set mixture. 02 not connected.
set idle with 02 connected.
introduce air leak- curious.

does ICV vibrate with key on.
can you remove it and and check to see what is going on in it.
you might go ahead and spray it with carb cleaner while off.

what if you adjust the idle while it is running?

don't let it idle for a long time while making adjustments.

if it idles fine and you are not fouling plugs and they look good at cruise, you may verify mixture, maybe at a shop, and just leave it along.

Yep, my Fluke arrives tomorrow to check the voltage on the O2 sensor.

Aside from this occasional idle bounce, which hasn't happened now in 2-3 days, the car runs really solid.

Those plugs are the old plugs, replaced with new copper core ones. I'll probably pull one to see this weekend, but they're barely 2 weeks old.

I set the idle with the car running and O2 connected.

Where is the O2 sensor plug? Which side do I measure? How does measuring Air Fuel with voltage on a voltmeter work? don't I also ideally need to test while driving and under load?

its better to check new plugs.