painless wiring tbi no fuel when cranking

[hammertime371]

hi guys...Im having some trouble with my v-8 s-10 conversion...used the painless wiring harness to install the tbi conversion..all is well but no fuel when cranking...if i pour some fuel in the tbi then crank it starts and runs no problem...if i shut it off it wont start unless i add some more fuel...seems like the ecm dont know im tring to start it...i got the correct brake switch installed and i have the park neutral indicator micro switch installed on the prostick shifter...not sure where i went wrong since all the wires are labeled on the harness...anyone have a clue as what could wrong??? thanks

btw i also have the ecm modded so i read and write the chip with autoprom

[dave w]

Maybe the Injectors are not being pulsed by the ECM? The ECM sends "Ground" to the Injectors to turn "On" the Injectors. The Injector Connector will have 12 VDC with the ignition switch in both On / Start positions. I suggest verifying the 12VDC is present at the Injector Connectors with the ignition switch in both the On / Start positions. Another option to verify the ECM is sending "Ground" to the Injectors is a tool called a Noid Light http://www.autozone.com/autozone/accessories/OEM-6-pcs-noid-light-set/_/N-26gh?itemIdentifier=948078_0_0_

dave w

[hammertime371]

well ive used a noid light befor and can get it tommorrow...It seems likely that there is no 12 volts when cranking...so how would we fix this?

[fastacton]

If you're not getting 12v during cranking, you're probably connected to the accessory side of the ignition switch. You need to find an ignition switched output that gets power in the start position as well as run. The original coil power wire is one place to start.

[dave w]

well ive used a noid light befor and can get it tommorrow...It seems likely that there is no 12 volts when cranking...so how would we fix this?

Troubleshooting is not easy, very accurate information is needed for me troubleshoot when the only tool I have is a keyboard.

dave w

[hammertime371]

actually you may have hit the nail on the head...very good point with the main power wire...will check that tommorrow asap!!! I have it pluged into the fuse box in a spot labeled power...I did check it for power when the switch is on and off when the switch is off...I didnt check it for power while cranking...:thumbsup:

[hammertime371]

so that was it dave!!! let me just clearify that its wasnt the main power wire as that hooks to the battery... it was the other power that works from the key...


BTW you wouldnt happen to know why a 700r4 dont have reverse gear after a rebuild???