LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

No ignition feed to PCM? Wiring gurus inside!

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Old Jun 4, 2006 | 11:22 PM
  #16  
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Re: No ignition feed to PCM? Wiring gurus inside!

Allright, so long as I have the wires connected to the fuse which is connected to the IGN, I should be fine right?
Old Jun 4, 2006 | 11:27 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by stingercamaro
Allright, so long as I have the wires connected to the fuse which is connected to the IGN, I should be fine right?
Plug onto the IGN terminal in the fuse panel. It is already fused. Sounds like you are trying to make this too hard.
Old Jun 6, 2006 | 03:03 PM
  #18  
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Re: No ignition feed to PCM? Wiring gurus inside!

I'm getting ignition feed Thanks guys

But I'm not getting hi or low res signal. That comes directly from the opti to the PCM, correct?
Old Jun 6, 2006 | 03:49 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by stingercamaro
I'm getting ignition feed Thanks guys

But I'm not getting hi or low res signal. That comes directly from the opti to the PCM, correct?
And you measured this how?
Old Jun 6, 2006 | 03:58 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by speedygonzales
And you measured this how?

I just took a test light to the PCM pins B2 (0 or 5 V) and B20 (5V). I know that you should probably be using a multimeter but mine's "gone missing" Also, since the fuel pump isn't kicking on and the injectors aren't pulsing, I figured that confirms a no low pulse problem.
Old Jun 6, 2006 | 06:48 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by stingercamaro
I just took a test light to the PCM pins B2 (0 or 5 V) and B20 (5V). I know that you should probably be using a multimeter but mine's "gone missing" Also, since the fuel pump isn't kicking on and the injectors aren't pulsing, I figured that confirms a no low pulse problem.
actually, they may have changed the fuel enable signal to the PCM in 96, since 93-95 used a VATS module, and 96-97 used the BCM, so that might be your problem, someone else I'm sure has looked into this
Old Jun 6, 2006 | 06:54 PM
  #22  
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Re: No ignition feed to PCM? Wiring gurus inside!

Gotta have that fuel enable signal to the PCM, whether from a VATS module, BCM or bypass module. Not sure I would use a test light on anything coming from the PCM, you might damage the circuitry.
Old Jun 6, 2006 | 07:25 PM
  #23  
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Re: No ignition feed to PCM? Wiring gurus inside!

So I need to run the fuel enable wire from the BCM? Or is possible to run it from the VATS?
Old Jun 6, 2006 | 10:56 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by stingercamaro
So I need to run the fuel enable wire from the BCM? Or is possible to run it from the VATS?
Whichever you have on your hybrid.
Old Jun 6, 2006 | 11:09 PM
  #25  
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by shoebox
Whichever you have on your hybrid.
In my 93, their is a silver box that attached under the dash on the passenger side. Is that the VATS module? If A25 requires 2.5 volts, what will happen if it receives more?
Old Jun 6, 2006 | 11:46 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by stingercamaro
In my 93, their is a silver box that attached under the dash on the passenger side. Is that the VATS module? If A25 requires 2.5 volts, what will happen if it receives more?
That's probably it. The signal is actually a modulated ground. You must use the signal from the VATS, a BCM or a specifically constructed bypass module (something that is sold for people doing LT1 transplants into other cars).

Here is a schematic for the VATS system with a VATS module. There should be two plugs on it.
Old Jun 7, 2006 | 12:25 PM
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Re: No ignition feed to PCM? Wiring gurus inside!

I've got the one metal, silver square with one plug and a small, black plastic box with one plug in. I went back to my camaro and pulled out the BCM. In the likely event that the plugs don't fit, is there any problem with me cutting and splicing it into place?
Old Jun 7, 2006 | 04:04 PM
  #28  
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Re: No ignition feed to PCM? Wiring gurus inside!

Sorry, the A and B cavities are in the same plug, not two like I was thinking-so there is one plug. It's a 16 way connector, but not all the cavities will be filled. The schematic I referenced shows all the color of wires going to it.
Old Jun 8, 2006 | 03:37 PM
  #29  
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Re: No ignition feed to PCM? Wiring gurus inside!

Can I simply fill any cavity in the BCM? http://shbox.com/1/pass_key.jpg I'm sorry but I don't really understand the diagram besides the fact that there should be a blue wire 229 going to the PCM.

Thanks
Old Jun 8, 2006 | 04:46 PM
  #30  
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Re: No ignition feed to PCM? Wiring gurus inside!

Originally Posted by stingercamaro
Can I simply fill any cavity in the BCM? http://shbox.com/1/pass_key.jpg I'm sorry but I don't really understand the diagram besides the fact that there should be a blue wire 229 going to the PCM.

Thanks
I don't know what you mean...

(that diagram is for a VATS module, not a BCM)



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