C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Diagnosing help needed!!

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Old Apr 2, 2003 | 12:45 AM
  #1  
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Swede
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From: Kyrkhult Blekinge
Default Diagnosing help needed!!

Hello!!
I have just siamesed my base, plenum etc + AFPR and put it all together and my baby is running good until 3 gear. I have done a couple of runs with TTS program and I have noticed 3 tenth better time but my mph is still the same, It seems like she just stops after 3000rpm. Could some friendly person look at my datamaster log and give me some advise ??
Thanks.
http://www.boomspeed.com/miniwipp/vette4.uni
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Old Apr 11, 2003 | 04:12 PM
  #2  
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tjwong
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From: Portland Oregon
Default Re: Diagnosing help needed!! (Swede)

Hey Swede,

At data point 3516 I saw 15 degrees of timing retard at 2800 RPM and you had over 10 degrees of retard until after 4000 RPM. I think looking at that losing 15 degrees is what is causing your engine to feel flat at the 3000 RPM point. Are you sure there are no vacuum leaks that may cause a lean out condition. Looking at your O2 voltage it does not appear that way. But there must be something causing knock retard, either poor fuel quality or actual detonation that the knock sensor hears and the ECM is responding to the signal.

Was the knock sensor ever removed for any reason? If it was perhaps it was installed and torqued down to tight, try loosening the sensor and retighten to 11 ft/lbs. Another thing to check is for any mechanical interference between the engine, headers or anything else that maybe hitting the frame or something else. Any mechanical interference that the knock sensor may hear could cause this.
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Old Apr 16, 2003 | 04:58 AM
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Swede
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From: Kyrkhult Blekinge
Default Re: Diagnosing help needed!! (tjwong)

Hello Tjwong!!
Thanks for your reply, I have checked the KS and reinstalled it and gone over the whole engine but cant find any things that may be wrong. It all ended up with my bad temper and a wirecutter and I simply cut off the wire to the KS . I have just make some testruns and you maby could give me some advise abot it. Maby I have to rent your services and buy a new chip from you?? (In this run I have installed an chip that I had lying around in the garage)
Here is a link to the latest runs:
http://www.boomspeed.com/miniwipp/vette10.uni
This is the newest test,,13,97,, soon I maby could go to the strip without making a fool out of me,? *lol*

[Modified by Swede, 10:59 AM 4/16/2003]


[Modified by Swede, 11:01 AM 4/16/2003]


[Modified by Swede, 7:37 AM 4/23/2003]
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Old Apr 16, 2003 | 02:38 PM
  #4  
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tjwong
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From: Portland Oregon
Default Re: Diagnosing help needed!! (Swede)

Swede, I didn't see the KR as I did on your last data run. But I did see a couple DTC error codes show up. On is for a high TPS reading it comes and goes. Take your ohmmeter set to volts and check the TPS sensor from closed (0) to wide open (100%) your reading should be linear. Check the sensor between terminals A and B. Terminal A is the sensor return which is sensor ground in the ECM, terminal B is the TPS signal to the ECM which is a 0 to about 5v signal. You should see a linear signal from about .5v to nearly 5v DC.

I am also seeing a intermittent coolant temp sensor failure. Check the coolant temp sensor connector, you may still have an early style sensor with the old coaxial connector. They were prone to failure as the sensor would start to leak coolant and the coolant would actually be forced into the insulation of the wire and go all the way into your ECM which would basically damage it. If you have one of these old style sensors replace it with a new GM replacement sensor. It will come with a new connector and pigtail assembly.

Also there I am seeing a interemittent EST fault, are you checking timing at this time by disconnecting the set timing connector?
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