91 350TBI to TPI (using an 89 FB System)

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Nov 24, 2010 | 10:27 AM
  #1  
I have seen the sticky's on related swaps, but this ones confusing for me and wanted to get some input.

So right now I have a 91RS with a 350 .030 over and its currently running on my stock 305TBI system(how im not sure)

I have a full TPI set up from a 89 Formula 350, My questions are basicly just about the harness aspect of it. Can I just re-pin the c100 to a c207 or do I need to use a c207 dash harness etc...? I do have the complete harness all the way down to the tail lights, but I would rather use mine since I know it all works and Im sure theres a diff. from a 91 camaro and a 89 firebird.

I have several pin out charts and im going to start compareing them and the harness' I have this weekend, just want as much imput as I can get
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Nov 24, 2010 | 03:03 PM
  #2  
Re: 91 350TBI to TPI (using an 89 FB System)
The c100 connector and the ip connector will both need to be repinned on the 89 harness, another alternative would be to convert the existing tbi harness to maf tpi, that way you can leave the c100 the way it is.
theres not that much difference between the tbi and the maf tpi harnesses maybe 6 or 7 wires that will need to be relocated and adding the injector plugs.
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Nov 26, 2010 | 07:18 AM
  #3  
Re: 91 350TBI to TPI (using an 89 FB System)
So your saying my best bet would be to follow that sticky about makeing your own TPI harness? Wait that one is a speed density system right? So how do I know what wires need to be moved etc...

Are you on NECF?
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Nov 26, 2010 | 08:19 AM
  #4  
Re: 91 350TBI to TPI (using an 89 FB System)
Quote: Wait that one is a speed density system right? So how do I know what wires need to be moved etc...
Major difference between the two is wires that would go to MAP on speed density go to MAF sensor on MAF ( '89 ) setup
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Nov 26, 2010 | 09:59 AM
  #5  
Re: 91 350TBI to TPI (using an 89 FB System)
follow the pin diagram from the 89 maf harness, you will need to splice in the connectors for the fuel injectors and maf sensor and relays.

the maf harness also has provisions for 2 fans, your tbi car most likely only has one, make sure you use the correct connector for the fan, you want the one operated by the temp switch in the head.

91 350TBI to TPI (using an 89 FB System)-1986-89_tpi_ecm_schematic.gif  

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Nov 26, 2010 | 10:39 AM
  #6  
Re: 91 350TBI to TPI (using an 89 FB System)
Quote: So your saying my best bet would be to follow that sticky about makeing your own TPI harness? Wait that one is a speed density system right? So how do I know what wires need to be moved etc...

Are you on NECF?
That would be my choice, the SD system.
Your harness could be converted real easy following the tech article.
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Nov 26, 2010 | 12:48 PM
  #7  
Re: 91 350TBI to TPI (using an 89 FB System)
You cad do s/d and save yourself a maf sensor and associated bits, repining is a little more involved, tho as the sd ecm has three plugs on it as opposed to two for the maf.
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Nov 29, 2010 | 12:47 PM
  #8  
Re: 91 350TBI to TPI (using an 89 FB System)
I wanna try and make this work with what I have, already have the MAF, intake, intake runners, throttle body, computer, etc...
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