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No voltage on bypass ECM output

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Old Apr 23, 2005 | 04:25 PM
  #1  
87Formula4bbl's Avatar
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From: Toledo, OH
Car: '87 Formula
Engine: 350
Transmission: Auto
No voltage on bypass ECM output

Does anyone have any ideas why there would be no output voltage on the bypass pin of the ecm? I finally got the car running again after some problems and I'm getting no voltage at the bypass pin. I'm stuck here.
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Old Apr 24, 2005 | 01:03 AM
  #2  
87Formula4bbl's Avatar
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From: Toledo, OH
Car: '87 Formula
Engine: 350
Transmission: Auto
One view in one day? Wow. Please someone read this, hehe.

Rundown:
Car starts finally after having a no-start situation forever (thinking it was bad distributor reference ground). I tested for continuity from the ecm harness for this and showed infinite resistance so I grounded it and it started right up. Maybe explains why when I would mess with the distributor (rotate it slightly) it would start, maybe its not getting grounded for some reason, who knows. Anyhow, it starts bottom line. But I think the module is not getting the bypass voltage from the ecm. I've checked and no voltage on the line. What gives? When I check the 'ESC Enabled' in Bit Date (TunerPro), it is enabled when it starts. But...if the module isnt getting 5V then it will not 'pay attention' to the ESC signal, according to my understanding. I'm about to just find a 5V source and run a line just to see if it will kick in the extra timing.

BTW, I know this because I zeroed out the idle timing table (it was in idle mode) and even tried the main spark advance table to no effect. Basically its running off whatever I set base at. And it is quit advanced just to get it to idle decently (almost as it should with the computer controlling timing).

Not to deliberately complicate the problem or anything, but also a strange thing happened today. I had pulled the emulator out to work with it in my brothers car, came back in the garage and kit the key and it fired right up.....without the emulator hooked up. The calpack that was on the moates adapter was an AUJP which has VATS (I don't have). Why in the world would it start with no chip, does the 'limp home' circuitry not check for VATS? I'm assuming this is what it started off of.

TIA, sorry for the length but I'm having problems undertanding exactly what is going on.
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Old Apr 24, 2005 | 10:18 AM
  #3  
884+3's Avatar
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Joined: Feb 2004
Posts: 225
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From: pa
Car: 88 irocz
Engine: b2l 350
Transmission: corvette 4+3
Was the vats bit disabled in the aujp bin while you were tring to start the car? On my 88 i dont have the vats hardware from the factory but that doesnt change anything. The engine still will not start.I tried emulating yesterday with an aujp bin that didnt have the vats bit disabled and car would not start.
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Old Apr 24, 2005 | 01:08 PM
  #4  
87Formula4bbl's Avatar
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Joined: Jul 2002
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From: Toledo, OH
Car: '87 Formula
Engine: 350
Transmission: Auto
Yes VATS is disabled in the bin on the emulator.
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