Any ideas on what is making this car go lean? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 04-11-2013, 08:45 PM   #21
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Loose connection maybe?
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Old 04-11-2013, 08:46 PM   #22
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Quote:
Originally Posted by Leafy View Post
When the clt sensor dies it almost always reads-34*F.
That's what I thought too.
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Did you try zeroing out all the correction tables?
I don't know the values to put back in.
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IE base is x and the total correction factor is x in a log?
Not sure, this is MS2 for those in the know.
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Old 04-11-2013, 08:46 PM   #23
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air bubble in the cooling system? bad sensor?

something
Doubtfull and air bubbles don't make AFR do that.
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Old 04-11-2013, 08:47 PM   #24
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Loose connection maybe?
It's been unplugged and put back a few times, I doubt it.
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Old 04-11-2013, 08:49 PM   #25
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Quote:
Originally Posted by hustler View Post
Doubtfull and air bubbles don't make AFR do that.
bubbles tripping out the clt that is calibrated to pull fuel when super hot? I dunno

that's why I was kinda wondering about what leafy said about zeroing out the table or making it go pig rich with higher temps: it will tell you for sure if jump in clt is causing the spike in afrs
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Old 04-11-2013, 08:49 PM   #26
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Well to rule out the clt sensor. Take the value from the current temp the ~200 cell, and paste it into the -34* cell (or the lowest one), and un-plug the sensor This will eliminate any effect the sensor could be having so we can cross it off the list of suspects.
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Old 04-11-2013, 08:50 PM   #27
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yeah something liek that
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Old 04-11-2013, 10:43 PM   #28
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He's got so som sort of issue with the MS or wiering look at 82 and 95 seconds in the log. Se the way the coolant sensor goes up in the same instance the map and tps goes down, also the indicated battery voltage goes down. At 128 he reduses throttle, map behaves normally, but colant and volt behaves odd. Grounding issue?

Tommy
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Old 04-11-2013, 11:26 PM   #29
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Hustler's not wondering about those instances. A sudden CLT jump related to closing the throttle and changing alternator voltage is an understood phenomena. What he's wondering about is the slow, cyclical change in CLT throughout the log . . . looks like a sine wave.

Honestly, it looks like the sensor is good but the CLT control is lousy. It seems to rise and fall in a delayed, smoothed response to engine load. I also don't see that AFR has a relationship to CLT in these curves.

Is the cooling configuration stock (no reroute)? Older T'stat? Don't forget that in this configuration, CLT is sensed at the back of the head by cylinder #4 while the T-stat is trying to control (and cool water is being ingested by the mixing manifold) at the front. Also, sometimes the little bleed line from the T'stat housing gets clogged leading to delayed control.

If rerouted, is the T'stat in the head or remote? A remote T'stat (M-tuned) could exhibit poor control in certain circumstances.

Last edited by hornetball; 04-12-2013 at 01:03 PM.
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Old 04-12-2013, 12:19 PM   #30
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Quote:
Originally Posted by hustler View Post
Most of that is static but filtered. That slight amount of TP, even if not filtered, should not create a 1ms PW adjustment. If you look throughout the log you'll find that small amount of TPaccel does not cause AFR to go lean.
that slight amount of TP looks like going from 6% to 0% in the second graph. when i'm at 0% throttle, my afr's go lean too, cos i'm not putting any fuel in. nor are you, PW goes to 0.

first graph has throttle position at 1% when you go lean.

how does it feel to drive, what's happening through the pedal?

i'd +1 to whoever said grounding btw.
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Old 05-02-2013, 11:27 AM   #31
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"how does it feel to drive, what's happening through the pedal?"

When driving until warm it drives normally. When warm is alternates between normal behavior and falling on its face. Basically I am driving along it stops pulling. The AFR gauge heads toward 18 - 22. Moving the gas pedal has no effect. If I back off it will recover and pull again. The last time I drove the car it was doing this relatively often.
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Old 05-02-2013, 03:00 PM   #32
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thermostat sticking or sluggish ?
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