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

Problems!!! Please help!!

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Old Aug 31, 2009 | 03:33 PM
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RJBAILEY84's Avatar
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Problems!!! Please help!!

I have a 95 z28 i just bought. it had a LT1 m6.. I also bought a 94z28 with a LT1 a4.
The 95 had no motor or trans so Put the 94 motor, tranny, computer, and engine wiring harness into the 95 body. I got everything install and i have no power to the fuel pump.... I ran a hot wire to the fuel pump and it puts 43lbs of fuel pressure to the fuel rail but will not start. .. I can spray a shot of starting fluid to the motor and it will hit and try to crank. So for some reason its not getting the fuel.. What could this be PCM, BCM????? Please help me out I love the car but its about to take a trip swimming in the river if i dont get it running ASAP... I have all the parts for the 94 if i need to swap something else. I just need to know what to do...Thanks in advance
Old Aug 31, 2009 | 04:05 PM
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You need to t/s the fuel pump circuit. Did you ck the fuse?
Old Aug 31, 2009 | 04:17 PM
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t/s ??????? the fuses are all good i changed each one out with all new fuses....
Old Sep 1, 2009 | 04:29 PM
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anyone have any ideas would it be the BCM since i put a 94 computer and auto trans in a 95 m6 car?????
Old Sep 1, 2009 | 07:22 PM
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95 and 94 don't have a BCM. The problem is your key in the original column. If the TDM doesn't recognize the key. It won't give the fuel enable signal to the PCM. You have to bypass the VATs by placing the original value resistor across the contacts (yellow wrapped wires) under the dash.

Tell us about which vats you have and which PCM you have.
Old Sep 1, 2009 | 08:26 PM
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PCM ???? VATS???
All i know about that is i put the 94 computer thats sits near the firewall under the hood on pass side in the 95 as far as anything else.... Im lost i know how to turn a wrench and plug some stuff up but this is my first project like this (LT1)... The electronics are killing me and i wanted this car running by the weekend.....
Old Sep 1, 2009 | 10:59 PM
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PCM is the computer. VATS is the anti-theft system that reads the resistance of the pellet in the ignition key to verify that it is the correct key. If the resistance doesn't match the theft deterent module value, its not going to tell the PCM to start the pump. Appears you may be using the 95 ignition switch and key with the theft deterent module from the 94, resulting in a resistance mis-match.

Courtesy of Shoebox:

http://shbox.com/1/pass_key.jpg
Old Sep 1, 2009 | 11:31 PM
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swap columns or get a key made with the other resistor in it, or do what they said and replace the resistor under the dash
Old Sep 2, 2009 | 05:10 AM
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Under the dash is 2 wires that are wrapped in yellow tubing. These go to the key switch contacts that touch the resistor pellet in the key. You need to disconnect the wires so they don't connect to the key switch any more. Then place a resistor across the 2 wires wrapped in yellow tubing that matches the resistance of the key that was used with the Theft Deterrent module you have now. Of course be sure to put the resistor on the end of the wires that go to the PCM, no the switch. Duh

Or you can get this
http://www.summitracing.com/parts/PR...024&view=1&N=0

However, I don't think any of us can help you with the painless product if you need help.
We can help you with the resistor method since I and several others have done it.

I might also suggest you understand the TDM, VATS system and how they interact with the PCM by at least looking at what Shoe has on his website here
http://shbox.com/1/4th_gen_tech2.html#pass_key
http://shbox.com/1/pass_key.jpg
And most importantly
http://shbox.com/1/pass_key.html

The days of stupid wrench turning are over my friend unless you want to stay in the carburetor days.

Last edited by Guest47904; Sep 2, 2009 at 05:15 AM.
Old Sep 2, 2009 | 06:35 AM
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Thanks for all the help guys.... i will get home today and try to bypass it. I would swicth the columns but the 94 has some other gm column in it. Its not factory.... Thanks again. And ill let everyone know how it works out by thursday...
Old Sep 2, 2009 | 06:45 AM
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just to make sure Where do you find the resistors to by pass the VATS do you use the pellets off the key? Or what ? Sorry if this is a dumb question...
Old Sep 2, 2009 | 12:56 PM
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use a dmm on the correct key to find out what resistor you need then go to radio shack and get the resistor. its probably <$0.50
Old Sep 2, 2009 | 03:09 PM
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Well i dont have the other key so im lost on where to start...
Old Sep 3, 2009 | 05:27 AM
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Apparently you ignored this
I might also suggest you understand the TDM, VATS system and how they interact with the PCM by at least looking at what Shoe has on his website here
http://shbox.com/1/4th_gen_tech2.html#pass_key
http://shbox.com/1/pass_key.jpg
And most importantly
http://shbox.com/1/pass_key.html

If you pay attention and read BEFORE you start asking questions you will be much better off.

On this page http://shbox.com/1/4th_gen_tech2.html#pass_key
It lists the 15 different values of resistors that could have been used. You purchase them from Radio Shack. To know how to read the color code for resistors see this
http://www.williamson-labs.com/resistors.htm
Since you don't have the original key to read, you will have to try some or all of the 15 different values until you get the right one.

Now start reading
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