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Old 05-28-2016   #1
Dafink
 
Join Date: May 2016
Location: Bergen County, NJ
Posts: 44
Default Code help h55 and h64

So my car is throwing codes h55 and h64. It's riding rough around 3000 rpms and the power seems limited.

Anyone familiar with this problem?
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Old 05-29-2016   #2
MuRCieLaGo
 
Join Date: Aug 2014
Location: Trois-Rivieres (QC)
Posts: 473
Default Re: Code help h55 and h64

We're two! See my thread here:

http://www.zr1.net/forum/showthread.php?t=26445

Keep me updated if you find something! Are your codes intermittent? What year is your ZR-1?

EDIT: I searched and I noticed yours is a 1991, just like mine.

Take also a look at this thread there:

http://www.corvetteforum.com/forums/...-and-64-a.html

Changing my o2 sensors is my next step.

Last edited by MuRCieLaGo; 05-29-2016 at 03:09 AM.
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Old 05-29-2016   #3
Dafink
 
Join Date: May 2016
Location: Bergen County, NJ
Posts: 44
Default Re: Code help h55 and h64

Seems like it's either the O2 sensor or ecm, leaning towards ecm since it feels like power mode is not getting selected. Does that make sense?
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Old 05-29-2016   #4
MuRCieLaGo
 
Join Date: Aug 2014
Location: Trois-Rivieres (QC)
Posts: 473
Default Re: Code help h55 and h64

What do you mean by "power mode is not getting selected"? For your information, when you got a SES light, you can't enable "Full engine power".
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Old 05-29-2016   #5
Dafink
 
Join Date: May 2016
Location: Bergen County, NJ
Posts: 44
Default Re: Code help h55 and h64

I think if there is an issue with the ecm it can result in the power mode being "unselectable"

Interestingly I drove it again this morning and it seemed to run fine, now I'm wondering how far to push it before diving in deeper.
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Old 05-29-2016   #6
bdw18_123
 
Join Date: Apr 2009
Location: Prather, CA
Posts: 809
Default Re: Code help h55 and h64

If the check engine light is on, the ECM won't let full power mode turn on, even if the code is not related to the secondary system.
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1990 Corvette ZR-1 [/B][I]
White/Flame Red, #2299, mostly stock, 144K miles.[/I]
-Cams timed to the '93-'95 405HP LT5 stock timing.
-IAT sensor relocated to below front bumper.
-Haibeck hoops installed in airduct.
-OBX cat-back exhaust.
[COLOR=DarkRed][B](SOLD - December 2012 [/B][/COLOR][COLOR=DarkRed][B]:hello:)[/B][/COLOR]

1993 Corvette Coupe
Black/Black, 6-speed
(SOLD - October 2009 :hello:)
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Old 07-13-2016   #7
Dafink
 
Join Date: May 2016
Location: Bergen County, NJ
Posts: 44
Default Re: Code help h55 and h64

Swapped out the injectors and all is good now....!
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Old 07-13-2016   #8
32valvesftw
 
Join Date: Jun 2015
Location: Texas
Posts: 530
Default Re: Code help h55 and h64

For future reference, the GM Service Technology Group Fuel and Emissions Course handbook, states that Code 55 is "Fuel Lean Monitor" It gives 3 possible causes
1. Secondary ignition insulation fault
2. Lean Injector
3. Inlet filter restriction to injector.

Code 64 is "right Oxygen Sensor signal-lean"
It gives several causes one of which is injector restriction - right bank

So it looks to me like you nailed it by changing out the offending injector. Good work.
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