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Vortec pcm help

bronc3buster842001

bronc3buster842001

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Ok all heres my problem. I have a tpi setup running the vortec pcm. I have power and ground to the pcm. The thing is i have no signal to the fuel pump relay or the check engine light. I can ground both and they work. Also when the coil is hooked up the ign. control module gets hot and the coil shoots sparks. I tried a different coil and module. I also have tried a different pcm. I built the wiring harness from scratch. Also when touching the pcm housing with a test light it lights up. Dont know if its suppose to do that or not. Sorry for the novel, but i need to get this figured out. Thanks
 
Please explain how you are running a vortec PCM with TPI. They are two totally diferent systems. Are the the drivers that run the injectors are even compatable?
Vortec has a bunch of sensors that control timing and ignition that TPI never had.
Vortec uses more 02 sensors. plus a bunch of other diferences.
Why not use a TPI ECM?
 
The drivers are compatible. I have all the sensors for the vortec. Do a search on Thirdgen.org or Fullsizechevy.com and you will see it is very easy to do. Dont want to use the tpi ECM because they are to hard to find.
 
Oh Ok. Didn't know you could use a Vortec ecm on TPI. Looked around on third gen Interesting.
Learned something new today.
Wish I could help you with your problem. TTT
 
Are you not getting a prime for the fuel pump, or do you get a prime, just nothing else?

Really have no experience with the Vortec PCM's, can only apply what I know about the TPI ones, and assume some functions are similar.
 
Thunder said:
Oh Ok. Didn't know you could use a Vortec ecm on TPI. Looked around on third gen Interesting.
Learned something new today.
Wish I could help you with your problem. TTT
Click to expand...


Ya it is interesting. They have TPI motors running with coil per plug setups. That will be a future mod for me.
 
Hmm, something else going on other than coil then I'm thinking, as the prime function is likely independent.

I'd be looking hard at the ECM and wiring. I'm assuming the Vortec setup uses a timed prime function as well, but it's simply a timer in the ECM, nothing else.
 
Stupid question, however the PCM "knows" the key is in run/start...are you 100% sure that works?

I'd almost want to start depinning all other wires from the ECM connectors and start with the prime circuit to see what is causing what problems, but that's a real pain. I'd first make sure that the wiring is actually hooked up right and that there aren't any wires that possibly got shorted on install.

Based on most posts where things are retrofit or built personally, the most common problem seems to be the power feed wires being tied into the wrong circuits, so power when they shouldn't, or no power when they should...
 
All power wires are good. I check all them. ! is a constant hot. 2 are hot with the key on. Im not sure on if the ECM knows the key is on. I dont even know where to check. My fuel pump and SES light circuits are good to.
 
You said when you touch the PCM housing with a test light it lights up?
The housing should be ground. Maybe you have a + and - wire hooked up wrong?
 
Yes it lights up. Dont remember if i had the test light hooked to a hot or ground. Ive checked all grounds and hot wires. Pretty sure all in the right spot. Will double check when i get home.
 
Sounds like some grounding issues for the case to light up a test light.

What year/part number is the computer? there are some minor variations between 96-2000.
 
bigblock72 said:
Sounds like some grounding issues for the case to light up a test light.

What year/part number is the computer? there are some minor variations between 96-2000.
Click to expand...

Ok I had 2 grounds in the wrong spot. Apperantly the grounds are different between a 96 and 97. Good thing i had the plugs for the ECM I'm using.
 
Just was going to post grounds are pins 17 and 18 on connector c3 (white).

Power at c1-14, c4-13 and c4-18.
 
Ya i had them a few off. It now starts and runs. Will try to get a video when I get the camera back. Thanks for the help guys. I figured it would be something simple.
 
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