TURN KEY=NO START AFTER MODIFING TBI HARNESS???

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Aug 26, 2007 | 04:27 PM
  #1  
alright well i converted from tbi to carb. i had it running, then i cut out some wires from the old tbi harness(alot actually) and now i turn the key and nothing happens. my lights all work and so does my radio etc just no start. heres all the wires i have hooked up, tell me what i missing please!!!! before i go nuts.

from the connector on the d/s firewall there are 3 wires(there a little thicker tahn the rest of the wires) that go to the starter, 2 reds and a purple.

i have a braided ground cable that goes from the back of the block to the firewall.

from the negitive terminal on the batttery i have it going to the frame rail

from the positive side of the battery i have it going to the starter and the other smaller wire thats on the positive side i have going to the junction block

ok so there used to be 3 wires that were on the junction block-the one from the pos. battery(still there), one from the fuel pump(removed,hardwired f/p), and one that went to ecm power. i know that all my grounds are good because i had it running before i decided to cut apart my harness.
any input is appreciated! im going to go insane if i cant get it fired up again soon! thanks, chris
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Aug 26, 2007 | 05:56 PM
  #2  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
It seems to be a problem with a break in the wire to the ecm. I am having the same problem with a similar swap in a 91 formula tbi. I am about to try to hard wire the ecm... i'll let you know when i get more figured out.
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Aug 26, 2007 | 06:02 PM
  #3  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
i removed my ecm, its carbed now and i eliminated my ecm so i shouldnt need power to it.
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Aug 26, 2007 | 10:37 PM
  #4  
Do you know what each and every wire you cut did?
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Aug 27, 2007 | 06:32 AM
  #5  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
well i traced most of the sensors to see which ones went to the ecm and which came from the firewall connector. when i was reading on here a few weeks ago i read that theres only 8 wires that u need to hook up to get a carb'd car running with full gauges?
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Sep 6, 2007 | 03:46 AM
  #6  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
from the negitive terminal on the batttery i have it going to the frame rail

Perhaps the problem? try grounding to the engine block ....
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Sep 7, 2007 | 02:57 AM
  #7  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
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Sep 9, 2007 | 08:55 AM
  #8  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
Was also going to say since it has VATS maybe thats the issue. Does your security light stay iluminated after the key is turned on? it should go out after maybe 5 seconds. If it doesn't locate the starter enable relay and jump the wires going to it ..... Maybe without ecm it see's it as a theft attempt for some reason.But I say it's your grounds though or maybe the crank fuse popped, check the vats fuse as well. Maybe a fusible link at the starter fried. turn key on and use a remote starter and see what happens if it doesn't crank then it cant be much more then the starter enable relay, ground wire from battery or a bad starter with a bad spot in it. But with remote starter if it does nothing then I say it is a ground problem more then anything. If it does crank then move onto the starter enable relay, crank fuse, vats fuse, heck could be nuetral start switch since you cut wires.
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Sep 9, 2007 | 11:53 AM
  #9  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
well i found the problem, i has just one little ground wire that was grounded and i hooked it up and it cranks! but now my issue is that it cranks but no start . before i cut uup the harness i got it started after a while of cranking it and mocing the distributor around but now that it cranks it wont start?? it has fuel and spark and the timing should be ok because it started before so im not sure whats goin on there. im gonna check spark in all the plug wires today and make sure its getting fuel. is there a wire/wires that i may have cut by accident to keep it from firing up?
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Sep 10, 2007 | 12:58 AM
  #10  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
did you swap distributors with the carb? your fighting a losing battle if your still using the tbi distributor.
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Sep 10, 2007 | 05:20 AM
  #11  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
hah no i didn't swap my tbi distributor onthe new motor. it has an msd non-cc distibutor now with a 6a ignition box.
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Sep 10, 2007 | 10:02 PM
  #12  
Re: TURN KEY=NO START AFTER MODIFING TBI HARNESS???
you are better off with the MSD setup the old TBI dissy would cause havoc.
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