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Old 05-19-2016   #61
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
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Default Re: Low RPMs bucking

Quote:
Originally Posted by MuRCieLaGo View Post
Put my hand near the flanges/clamps and I felt some air.



I really need to do some researches regarding that closed loop thingy. I'm not sure I understand how it works.

Thanks a lot for your help.
Closed Loop means that the ECM is using O2 sensors as one of the inputs for calculating injector pulse width. The VE tables are the main fueling tables and then the ECM utilizes O2 sensors to modify those values. There's more to it but this is the basic operation.
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Old 05-21-2016   #62
MuRCieLaGo
 
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Default Re: Low RPMs bucking

Small update today:

Been running with the car, knocking noise seems to be GONE since I changed the spark plugs...

New code showed up once today:

Code 42 - Electronic Spark Control Error.
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Old 05-25-2016   #63
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Default Re: Low RPMs bucking

Exhaust leak fixed - no change at all.

Gonna order two new o2 sensors.
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Old 05-31-2016   #64
MuRCieLaGo
 
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Default Re: Low RPMs bucking

Receiving two NGK NTK o2 sensors tomorrow. Meanwhile, car developped another symptom: stalls randomly at red lights (starts perfect when I crank it back).
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Old 05-31-2016   #65
XfireZ51
 
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Default Re: Low RPMs bucking

Could you recap the changes you made prior to all this happening?
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1992 Corvette ZR-1 Black Rose/Cognac #458
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Old 05-31-2016   #66
MuRCieLaGo
 
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Default Re: Low RPMs bucking

Quote:
Originally Posted by XfireZ51 View Post
Could you recap the changes you made prior to all this happening?
Good idea

RECAP

Problem: low rpm bucking, especially when cold. Stalling at red lights (restarts like a charm). Got codes 55 and 64 once, erased them and they never came back. Also experienced a strange knocking/rattling noise, which went away on its own.

-Electrically tested the injectors, hot. Got between 17.3 and 17.9 ohms everywhere.
-Spark plugs changed.
-Fuel pumps removed, visual inspection done: nothing was wrong.
-Fuel pressure tested. Idle: 41 psi, FP1: 46 psi, FP2: 48 psi.
-Fuel filter changed.

Receiving two NGK NTK o2 sensors tomorrow.
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Old 06-01-2016   #67
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Default Re: Low RPMs bucking

I think you have a bent DIS PIN
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Old 06-01-2016   #68
MuRCieLaGo
 
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Default Re: Low RPMs bucking

Quote:
Originally Posted by LGAFF View Post
I think you have a bent DIS PIN
I searched and I found this thread, which shows the connector. However, where is that connector?

http://www.zr1.net/forum/showthread.php?t=20184

Should be easy to check?
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Old 06-01-2016   #69
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Default Re: Low RPMs bucking

under the plenum at the back of the intake
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Old 06-01-2016   #70
MuRCieLaGo
 
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Default Re: Low RPMs bucking

So...

1. Change both o2 sensors.
2. Remove plenum and check for that connector.

Should I check something else while the plenum is removed?
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