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

1995 D/A with TunerPro RT

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Old Mar 11, 2017 | 03:17 PM
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Default 1995 D/A with TunerPro RT

Would anyone have nothing else better to do than decypher some log files? Or at least point me to where I can see what factory valus should be? No codes or errors. Nothing looks off based on my limited knowledge. The car sat 4 years outside before i got it and it idles and runs a little rough. Thinking it needs new injectors since i've replaced the opti, O2's, & TPS.

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Old Mar 11, 2017 | 04:24 PM
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if you have a datalog post it up
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Old Mar 12, 2017 | 05:13 PM
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Default D/a

The first 3 are done with TunerPro RT using $EE-16188051-Y-body-V3.8.adx. The other two were done with EEHack. Any input is greatly appreciated.

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Attached Files
File Type: zip
data logs.zip (1,013.5 KB, 16 views)
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Old Mar 12, 2017 | 10:06 PM
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Your IAC at idle is at 0 when engine is warmed up. You need to adjust your throttle body idle setscrew to close your throttle blades a bit. This will increase your IAC position . Try and get the IAC at about 40-50 for idle.
You are getting knock retard up to about 13 degrees pulled back during certain load conditions
There is also a DTC Code 78= FAN 2 FAULT

Last edited by FrankieD; Mar 13, 2017 at 12:10 AM.
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Old Mar 14, 2017 | 12:34 AM
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Originally Posted by FrankieD
Your IAC at idle is at 0 when engine is warmed up. You need to adjust your throttle body idle setscrew to close your throttle blades a bit. This will increase your IAC position . Try and get the IAC at about 40-50 for idle.
You are getting knock retard up to about 13 degrees pulled back during certain load conditions
There is also a DTC Code 78= FAN 2 FAULT
i usually don't run premium gas so that may have something to do with the knock. I also get a knock on a hot start. I have my fans hard wired to a manual switch. I hope to get a new flash uploaded with lower fan values so I can rewire them back to oem.
Do you know what it takes to adjust that screw? I wasn't able to see into the recess.
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Old Mar 14, 2017 | 11:17 AM
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If I recall correctly. I believe it is a Torx T-20
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Old Mar 18, 2017 | 06:04 PM
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Default Throttle body adjustment

thanks, it was a t15 for mine. I made the adjustment but with continued AIC going to 0. I did a smoke test and found my throttle body leaking air around the top plate and through the throttle blade shaft on the cable side. Smoke was coming through the springs. I assume I'll be getting a new throttle body since I don't think I can replace the seal on that side.
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Old Mar 18, 2017 | 09:00 PM
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I say your IAC is bad. It will not give a code, and if at ZERO, it is broke. Take it out, do a test on it with a ohm meter, and I bet you see its bad. Search for the test.
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Old Mar 18, 2017 | 09:01 PM
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wondering how bad of a vacuum leak that is causing. Can you try to back the idle set screw all the way down until the throttle blades are completely closed and the screw is just off the lever. Now turn up the set screw about 1.5 full turns until you can see throttle blades just opened from being bottomed out. Then can you read what the IAC is at that point. Remember to do this adjustment when the engine is fully warmed up. Trying to find out how much the IAC is compensating to set the targeted idle because of any leak.
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Old Mar 18, 2017 | 09:14 PM
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Tuner Pro will only who you what the ECM is telling the IAC to do, not what it is actually doing., Trust me on this.
Use an OHM meter and check between A and B? Should be greater than 20 OHMS. Check OHMS between C and D should be greater than 20 OHMS? If not replace IAC.
Not sure of color code, but
Blue wire white stripe to A on IAC connector.
Blue wire black stripe to B on IAC connector.
Green wire white stripe to C on IAC connector.
Green wire black stripe to D on IAC connector.
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Old Mar 20, 2017 | 05:10 PM
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Originally Posted by krackenvette
Tuner Pro will only who you what the ECM is telling the IAC to do, not what it is actually doing., Trust me on this.
Use an OHM meter and check between A and B? Should be greater than 20 OHMS. Check OHMS between C and D should be greater than 20 OHMS? If not replace IAC.
Not sure of color code, but
Blue wire white stripe to A on IAC connector.
Blue wire black stripe to B on IAC connector.
Green wire white stripe to C on IAC connector.
Green wire black stripe to D on IAC connector.
IAC checked out at 51 & 55 ohms. SHBOX.com mentioned anywhere between 40 & 80.
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Old Mar 20, 2017 | 06:30 PM
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Originally Posted by Slythee
IAC checked out at 51 & 55 ohms. SHBOX.com mentioned anywhere between 40 & 80.
Oops. GOOD DEAL

Last edited by krackenvette; Mar 20, 2017 at 06:31 PM.
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Old Mar 20, 2017 | 11:08 PM
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Good luck! Frankie knows his stuff. I can't read the log because I'm on a Mac.
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Old Mar 21, 2017 | 09:37 AM
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Originally Posted by FrankieD
wondering how bad of a vacuum leak that is causing. Can you try to back the idle set screw all the way down until the throttle blades are completely closed and the screw is just off the lever. Now turn up the set screw about 1.5 full turns until you can see throttle blades just opened from being bottomed out. Then can you read what the IAC is at that point. Remember to do this adjustment when the engine is fully warmed up. Trying to find out how much the IAC is compensating to set the targeted idle because of any leak.
From what I could tell, it was at most, 1.5 turns in to begin with. I backed it out to where it wasn't contacting the lever then back in maybe a 1/4-1/2 turn, just enough to know it wasn't going to stick. I'm making a new gasket for the throttle body top plate and will do another run and post that log. BTW - I also did a injector test with a pico scope where I measured the pulse width, voltage, and current. They are all pretty consistent. You can see the results on my YouTube channel slythee1. Maybe you can see something we didn't.
THANKS FOR ALL THE INPUT.
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