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09-18-2005 | #1 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Interpreting Scan tool data
Hi guys, I borrowed a snap-on scan tool. I don't know what to do with the data. In my 90 Z's shop manual there is a page, 6E3-A-14, that has an example of what a normal 90Z's data should look like. I used Gordon's jumpers to look for codes in the ECM and CCM & didn't find any.
The scan tool said there were "history" codes H46 & H54. The scan tool said there were no current codes. I wrote down all the data that the tool gave while the motor was running in closed loop. TPS = .54v angle = 0% Left Int. =107 Right Int. = 126 to 131 think this is "counts" Helm says "varies spark adv. = 8* Helm says= 0* left BLM = 115 Right BLM = 126 Helm says 118 - 138 BLM cell =4 Is this = Block Learn Cell, Helm says = 0. Battery V = 13.4 Helm says = 13.5 to 14.5 Fuel pump V = 13.4 and the 2* fuel pump = on. I don't get that, H2O = 219* MAT = 109* Cross Count, left=12 right=0 to 1 BPW, left=3.8 ms right=4.3 ms MAP v=1.32 to 1.34 Kpa=34 The snap-on tool seems to use different language than the page in the Helm book, so I'm lost. The car smells lean and has a miss at idle and up thru the rpm range. Any light thrown my way would be appreciated. Thanks, Tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
09-19-2005 | #2 |
Join Date: Aug 2005
Location: NY
Posts: 143
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Your left side fuel metering is too far off scale. The integrator (short term) and block learn (long term) ideal is 128. Block learn can go off scale and have the integrator compensate (add or substract fuel) as shown by a 128, but with a 107 integrator reading, you have a problem that the system is not able to compensate for and requires repair.
Does the oxygen senor reading mv go from approx 50-850 in a fast manner? If not, it could be a failing sensor, but I suspect its something else.
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Mike 427 cu in LT5 [URL="http://zr1mk.weebly.com"]http://zr1mk.weebly.com[/URL] |
09-19-2005 | #3 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Thanks Mike! First for instructing me on "long term" & "short term".
O2 mv readings were: Left O2 = 100 to 700 Right O2 = 93 to 700+ I don't know how fast they were changing. I didn't know to pay attention but I remember the right reading was changing almost too fast for me to take down numbers. The left one was changing slowly so I could keep up. I forgot to include those #'s because I didn't know that they were important. Sorry. Thanks for the help, Tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
09-19-2005 | #4 |
Join Date: Aug 2005
Location: NY
Posts: 143
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The Corvette manual gives descriptions of your monitiored info. The latest Corvette Fever magazine also has a technical article to help you understand many of the items you mention.
You have a rich condition on the left side. Reference the codes and diagnosis as outlined in the manual. The actual oxygen sensor readings are good when you dont have time to actualy read them. The integrator and block learn will proces the info to read.
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Mike 427 cu in LT5 [URL="http://zr1mk.weebly.com"]http://zr1mk.weebly.com[/URL] |
09-19-2005 | #5 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Thank you again, Mike! Okay first I will look up rich conditions and see those diagnostic charts. Second I will go to Corvette Fever and see about an online subscription.
Thank you for the time you took to help me out! I've been away for 20 yrs and the Z is too much technology for me to swallow this quickly. A 72 LT-1 was such a simple car comparred to this marvel. Thanks again! Tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
09-19-2005 | #6 |
Join Date: Aug 2005
Location: NY
Posts: 143
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I am always glad to help. I know how you feel as my previous car was a 1970 Z28 and the ZR1 is my first Corvette.
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Mike 427 cu in LT5 [URL="http://zr1mk.weebly.com"]http://zr1mk.weebly.com[/URL] |
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