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High idle and Cruise 'idle'...
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Author:  Z-type [ Tue Jun 21, 2011 10:22 pm ]
Post subject:  High idle and Cruise 'idle'...

Hey guys...got one I need some help with this time, if you please :).

I have a '00 SSEi with a 180 degree thermostat and AL605 spark plugs, and Intense FWI. No other mods. The problem started this morning when I started the car. Idled normal for about 10 seconds then idle jumped from 1000 to ~1500. Weird. So I let it sit for 30 seconds or so and it came down to 1200. I got on the road because I had to get to work, and the car coasted at high enough an RPM that the car was actually accelerating itself on flat surfaces (35 mph, 3rd gear, 1700 RPM). No engine light.

So I stopped about 2 miles from my house seeing this was a problem, popped the hood and heard no obvious leaks or anything visually awry. I shut off the car, started it back up, everything operated perfectly.

After work (10 hour shift), car did the same thing...idle started fine and popped up to 1500. I shut off the car and started it again and it was fine all the way home. :dontknow:

I did have my scanner with me the entire time but didn't think to plug it in. I know you guys probably need more information (from the scanner) and will be glad to provide what I can, though my scanner is limited in what I can view.

Thanks for your help everyone!

-Andrew Z

EDIT: Just scanned the car real quick. The idle didn't jump at all. The IAT was 110, and my LTFT was 16.4. No good. My first instinct is vacuum leak, but there's a storm brewing outside. - I'll have to play with it tomorrow. Any new thoughts now?

Author:  00Beast [ Wed Jun 22, 2011 12:52 am ]
Post subject:  Re: High idle and Cruise 'idle'...

Sounds like a vac leak. Check all the connections really well, especially the T under the snout of the S/C. If you don't hear or feel anything, spray the lines with carb cleaner while the engine is idling and see if the idle drops to normal for a sec. If it does, you found your culprit.

Author:  Jrs3800 [ Wed Jun 22, 2011 10:56 am ]
Post subject:  Re: High idle and Cruise 'idle'...

I agree but also want the Op to check the TPS voltage and or %, this needs to be steady, if it changes on its own say at idle then you may have a bad TPS...

Author:  Z-type [ Wed Jun 22, 2011 3:47 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

Thanks guys. I had an opportunity last night to scan the car, but the car was still warm at the time. The idle didn't jump up like it did the last two cold starts, so I saved it until morning. This morning actually.

SO i plugged int he scanner before starting the car, had a steady IAT of 77 and coolant was 80. Started it up and it ran like nothing ever happened. Now I did notice the LTFT was maxed at +16.4, which I understand is running lean. But that was just at idle, at 950 RPM. I let the car run and monitored it for 2 more minutes and took it for a 2 mile drive. Nothing out of the ordinary. The LTFT acted normally until I let off the gas, where it leaned to +16.4 every time. The guys at the Riviera board think it's possibly a vacuum leak, but maybe the IAC could still be acting up.

Ed - I did a vacuum leak test when I got home since the engine was nice and warm (183 degrees). Didn't find a darn thing as far as a leak is concerned. Everything appeared great.

The TPS when I scanned today was steady, and rose and fell appropriately with the throttle. Of course, i didn't have an idle problem today either...

When I get a chance I'm going to clean the throttle body...probably not until next week at this point, or maybe Sunday. Going to clean out the IAC and IAC passage specifically.

Author:  Z-type [ Tue Jun 28, 2011 12:47 am ]
Post subject:  Re: High idle and Cruise 'idle'...

Sorry for no updates lately everyone. Just the usual...annoyingly busy.

I haven't had a chance to clean the throttle body, and now I don't know when I will. But I know I HAVE to do it, since I realize I haven't done it right yet. (a rare thing for me - not cleaning thoroughly)

I did want to update and say that the car has not acted up one bit since I made this post. The idle has been perfect at idle when cold, and when cruising and warm in Park/Drive. I haven't scanned the car the last couple mornings but I can't imagine the fuel trims have changed much.

Thanks guys...I'll update you when something happens!

-Andrew Z

Author:  Z-type [ Sat Jul 09, 2011 8:28 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

Alright...car is no longer perfect. The car's idle did it's thing again this afternoon and went up to 1500 on it's own like before. Fine...I can deal with that once or twice. So I shut off the car, turned it on again, and it was fine. For about 5 seconds. So I popped the hood and unplugged the IAC, and nothing changed. I figure it's a safe bet that the IAC is probably stuck...or at least cruddy. I'm going to replace it, and I tried to take mine out to check it out, but I broke the head of the top bolt.

fdjsoghuisdanfdosajhguidsanfuidsaf

So now I guess I have to find a bolt remover thing small enough and replace the IAC....a week before I leave for vacation. With one day off. Fun! Luckily, there's no vacuum leak at the IAC. The sensor is still secure even with the bolt head broken.

Author:  Z-type [ Sun Jul 10, 2011 6:47 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

Ok I replaced the IAC. Nice shiny new BWM or BDW or whatever that brand is. I can't remember for some reason. Anyway, I cycled the ignition on and off twice and did a re-learn - everything SEEMS ok. and normal, if not a smoother idle (if that makes any sense).

For some unknown reason, no local stores have throttle body gaskets, and they don't carry them (wtf?) so I'll be waiting for one in the mail before i clean the TB completely. I did do a decent cleaning of the IAC chamber which actually wasn't all that horrible.

Author:  Z-type [ Mon Jul 11, 2011 9:06 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

I don't think the IAC is my problem anymore. I am about 99% sure it's the TPS. The car acted the same today as it did the last couple times the problem has popped up, and I had my scanner in the whole time. I noted a reading of TPS 2.4% while coasting, in any gear, any speed. I did another rest/relearn process...the car started at a TPS reading of 0.0 at startup and coasting, then halfway through the drive the problem came back. It read 3.7% at one point (no actual throttle of course) and then dropped to 1.6% and back up to 2.4%. All on it's own. I will check the sensor with my meter but I'm not sure it's necessary. Opinions?

If I do change the TPS, should I do another re-learn?


EDIT: I re-read your post Don, and I guess you're right. An unsteady TPS = problems.

Author:  repinS [ Mon Jul 11, 2011 10:43 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

I'm chasing the same problem with the Northstar right now, it did this for a good few weeks and finally threw a P0122 this week. Going to try and test / fiddle with it before replacing the sensor.

Code:
P0122 Code - Throttle Position Sensor/Switch A Circuit Low Input

Author:  Z-type [ Mon Jul 11, 2011 10:58 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

Thanks Repin. Luckily I don't even have a pending code...yet. I would like to mess with my sensor too, but I have to get this fixed before Saturday. If not, I'll have to take my dad's '04 Regal GS to the beach and while I'm a Buick guy, the Regal is a smaller car ;) . Can't have that.

Author:  repinS [ Tue Jul 12, 2011 8:48 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

I was actually happy that I threw the code! I don't nearly have the time to poke around and diagnose my idle. Now I know where to start :p

Author:  Z-type [ Mon Jul 25, 2011 11:14 pm ]
Post subject:  Re: High idle and Cruise 'idle'...

Just wanted to update this thread a bit. Been fighting this issue for a few weeks now, I think I made a little progress.

The TPS was indeed acting up as stated in a previous post in this thread, so I got a 'new' one from Advance and it was bad out of the box. I put my old one back on and the car was fine for about a week. It started acting up again so I got a spare TPS from harofreak here on the board. I just swapped it in tonight and did the following:

Installed sensor (battery was still connected...oops)
Checked TPS position with my scanner...it read 0.6%
I cycled the ignition on/off twice and it read at 0.0%
Took it for a ride and the idle problem came back, with the TPS position reading 5.2% while off the throttle
Got back to the house and disconnected the battery, touched the cables together to drain the PCM capacitors
Checked the TPS again and it said 0.0%
Just out of curiosity, checked the TPS wiring again and it read +5.0v
Took it for a ride and everything was happy and dandy.


Anything else I should have done, or should do now? I was going to take the T-type to work tomorrow but I'll take this thing to make sure it behaves.

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