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Power FC closed loop+very light throttle=jerky

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Old 01-24-02, 09:54 AM
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Hey, where did my $$$ go?

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closed loop+very light throttle=jerky

I know we had a thread about this a long time ago but I think its gone. I tried searching for it but couldn't find anything.

During closed loop with very light trottle (letting on and off around town) it gets jerky as I let on and off. Its not real bad but its kinda annoying.

What was the fix for this???

Thanks,
STEPHEN
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Old 01-24-02, 10:21 AM
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The cure is a little more fuel. I have added fuel to my light cruise area to smooth this out and to increase throttle responce. I only have the problem when lugging 1st gear around 1500rpm but have left that area alone to keep the exhaust cleaner.

If you look at the area P05 to P09 for N03 to N08, you will see a lot of 100s surrounded by higher values.

Look at the attachment, map 1 is base stock, map 2 is mine, 3 is the delta. See the fuel I added to complete the pattern of the area.
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Old 01-24-02, 01:33 PM
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Hey, where did my $$$ go?

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Thanks Chuck,

I figured it just needed a little more fuel but thought I'd ask about it just to make sure.

I'll do that during lunch and let you know how it turns out.

Thanks for the help,
STEPHEN
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Old 01-25-02, 09:23 AM
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Thanks Chuck, I plugged in the numbers you had and it helped alot.

The light throttle jerk is now cured. When I take my foot completely off the gas it still bucks around some but not near as bad.

Thanks for the Help,
STEPHEN
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Old 01-26-02, 01:26 AM
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If it bucks when taking you foot off the throttle, then your dash-pot
or PFC(page 33) deceleration fuel cut recovery rpms are not set correctly.
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Old 01-27-02, 11:53 AM
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Ok, thats interesting, I've seen that in the manual but didnt really know what it did. How do the Deceleration fuel cut recovery rpm settings work???? I'm dont understand the concept behind these settings, what are they actually doing. What are the stock settings, or what settings are you using??? XS probably changed mine.

What is dash-pod??? I've never heard of this?


Sorry for all the questions,
STEPHEN
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Old 01-27-02, 12:37 PM
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I think I have the same problem. If I'm under light throttle and give it some gas it stutters momentarily then pulls without a problem. I also notice it in neutral. When I tap the throttle the revs either drop or stay the same THEN rise. Is this the same??

Chris
PFC, dp, cb, intake, clutch/flywheel, passive rear wheel steering system by Boston potholes inc.
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Old 01-27-02, 04:48 PM
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Dash Pot, the green pot by the throttle linkage with the white plunger that contacts the linkage. It prevents the throttle from closing instantaneously by slightly delaying it.

When you let off the throttle, the injectors are turned off until the revs drop t this "SET POINT" (rpms). Then they are turned back on for idle.

Set 200 to 300 rpms over their corresponding idle speed.
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Old 01-27-02, 08:39 PM
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It is set 200-300 over the idle speed. The prob happends when I stay in gear and just take my foot off at say 3000rpms so the tach never drops. I played with the settings and it didnt help. I think the recovery rpm setting is for when you drop the rpms all the way down.

The dash pot is something I'll can look at in the next day or so, maybe that will be the prob.

Thanks for all your help
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Old 01-28-02, 08:11 AM
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Also check for sticking throttle linkage.
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