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Old 07-17-2008, 02:54 PM   #1
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Default Idle bounces... Boing, Boing, Boing

megasquirt200807170956.zip

Here's the latest file I'm running. Car runs really well with a couple of exceptions. Popping/ hesitating under full throttle and a bouncy idle. Gapped the plugs to .25, helped but didn't stop the pop completely. Too rich at WOT? Seeing low 11's on the gauge. Have it set to 12 in the AFR tables.

Biggest headache is the idle. Rich/lean/rich/lean/rich/lean....

Sometimes it's dead on idling mid 13's. Most of the time not. Warm, cold, doesn't matter. Noticed the same issue when parked if the throttle is depressed. Doesn't hold a steady rate. Same bump up and down over and over. Doesn't seem to do this when the car is moving, just in neutral.

Don't know if anything jumps out to you gugu's as being strange. Let me know what other information might be helpful!

94, 1.8l, S4 system w/ 2860rs. EBC, 2 1/2" enthuza exhaust, 2 1/2" metal cat, 550cc Rx7 injectors, Maf kicked to the curb, AEM Uego wideband.

While the car is idling I was watching the VE, AFR and timing tables. Tried to get everything to the same numbers in the cells it was using at idle. Didn't stop it. Don't know if I have some conflicting numbers somewhere or what?

Hitting the Dyno Monday. Improve the tune, solve the pop at WOT issue, see where it's at power wise and make sure my WB is accurate.
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Old 07-17-2008, 03:09 PM   #2
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need a log file too!
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Old 07-17-2008, 03:10 PM   #3
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but id look at your idle control settings and figure out why you have 0 for minimum and closed dc......
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Old 07-17-2008, 04:05 PM   #4
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How do I put up a log file? Attachment doesn't accept xls. files that I can figure out! Geez I'm incompetent.

Screen shot work?


If anything but 0 and 0 is entered the idle goes nuts. I've tried some of the numbers others used and the idle jump up to 2000 rpms and still fluctuates, just at an obnoxiously high idle.
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Old 07-17-2008, 04:18 PM   #5
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Idle bounces...  Boing, Boing, Boing-graph.png

Here is a screen shot during idle. Don't know if it helps.
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Old 07-17-2008, 04:38 PM   #6
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Here's part of the log. Cut it down so it would fit the forum. It's in the XLS form. Is that OK?

Oh, crap. 1st one was xlr - changed to xls. Sorry.

datalog (2).zip
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Old 07-17-2008, 04:41 PM   #7
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nearly all your settings match the PNP in that respect, those and the TPS threshold....


first the minimum dc is supposed to be the duty cycle slightly lower than a warm idle dc when regulated.

closed, is obviously the dc it closes....both on the PNP map are 9.


the TPS threshold is the point above which the idle valve closes in ADC. You have it set to 27. PNP is 40.

I assume if that is set too low, MS wont even control the idle valve.
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Old 07-17-2008, 04:48 PM   #8
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I followed instructions for setting the TPS threshold. It is the closed setting when I clibrate the TPS + 4. The calibration # I get with my foot off the gas is 23 or 24. That's were the 27 came from.

I'll try working with the duty cycle #'s. See what happens. Anything else jumping out to anyone? Conflicts between setting?

Curious about the idle valve frequency? Is it the same on all cars? If not what's used for 94's?
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Old 07-23-2008, 02:38 AM   #9
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OK, this is driving me nuts. Again, 70% of the time it's bouncing around. Rich/lean/rich/lean. Does the same thing with no load and part throttle, say 2500 rpms. I've tried just about every possible combination of numbers for the IAC. Disconnecting the IAC. Adjusting the throttle plate, the fine tune screw. All the possible tables - VE, AFR, Spark - so that all the surrounding cells at idle are the same. Cold, warm, hot, doesn't matter. Moved GEGO to control down to 1000rpms, up to 2000. No effect. It'll idle perfectly stopping for one light then bounce around for the next 10 stops.

Any ideas? Could it be in the wideband? Gego on or off doesn't seem to matter. Was annoying, now it's pissing me off. rich/lean/rich/lean GAAAAH!
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Old 07-23-2008, 02:51 AM   #10
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I have the same problem it seems. I would bet it isn't the wide band, as the problem didn't change when I had to switch wide bands from LC1 back to UEGO. Honestly I haven't even started trying to figure it out, so I am of no help at this moment, sorry.
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Old 07-23-2008, 03:08 AM   #11
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It seems there are a number of us with the bouncing idle bs. Hopefully we get it figured out! Keep posting.
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Old 07-23-2008, 10:18 AM   #12
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Quote:
Originally Posted by cueball1 View Post
It seems there are a number of us with the bouncing idle bs. Hopefully we get it figured out! Keep posting.
highres code? I hear this is typical with big injectors.
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Old 07-23-2008, 10:50 AM   #13
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what's the idleDC look like when it does it....is it worse/better when you disconnect the idle valve outright?
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Old 07-23-2008, 11:35 AM   #14
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I couldnt get a clean idle either with closed loop PWM. i just went to "warm up" which just means open loop really, nothing to do with warm up then set the cold and warm thresholds as well as the temps and it works surprisingly well. ideally i would like to get closed loop to run well but i figured i'll mess with it later.
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Idle bounces...  Boing, Boing, Boing-idle.jpg  
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Old 07-23-2008, 12:53 PM   #15
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Compuatic, I'll try the warmup setting. Thanks for the suggestion!

No change with the iac hooked up or not. With the std 9/9 setting or 0/0 or lots of other number combinations.

Here's another screen shot.



Quick dummy question. You have the idle plate screw. There is also the hidden screw set into the hole above it. For most people is that screw run nearly all the way in or backed off quite a bit?
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Old 07-23-2008, 01:35 PM   #16
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something's wrong with your MAP line....
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Old 07-23-2008, 02:50 PM   #17
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The physical line or what you see on the screen. I tried changing where it's plugged in, from the port DIY shows to sharing the port on the very back of the manifold. No change.

What I can't figure is what is leading what. Is the map varying and setting off the other stuff. Are the Afr's driving it. Timing. The Pulse width keeps bouncing from 1.7 to 1.9 along with everything else. Again, the same rich/lean/rich/lean crap is happening when I rev to say 2500 rpms when parked. Revving like that the fuel cuts completely making the rpm swing much wider.

Is there a conflict somewhere in the program?
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Old 07-23-2008, 03:03 PM   #18
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that map line looks whack... its hold flat at 31 then dropping to 29, then back...

It's almost like the software is forcing that map, and not using the acutal values for fueling.... not sure.
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Old 07-23-2008, 03:30 PM   #19
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Old 07-23-2008, 03:32 PM   #20
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DIY emailed and said my VE tables might be asking for too much fuel down low. I ran megatune with just an idle log and it agreed. I'm going to try dropping the VE tables between 500 to 2500 rpms in the 20-40 kph range. Laptop just died and my charger is at home. I'll have to try this tonight.

Compuatic,

I switched to warm up only and it does work that way. Just running off screw settings. Idle is steady but the rich/lean/rich/lean thing is still there. I'm considering it a temporary fix until I get the Map/AFR/RPM thing figured out. Thanks for the suggestion. It makes the car less anoying to drive while I figure out the problem!
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