two blazers twice the headache

hi fellow knuckle bangers, my 96 s-10 blazer 4.3 l vortec is not getting power to ignition module or coil. i have checked all fuses in drivers compartment and fusible link coming from positive terminal of battery. i believe ignition switch is good because i do hear fuel pump on with key on. any ideas what my problem could be? thanks in advance.

EinST

Welcome to the forum. Both the ignition coil and ICM gets the ignition voltage (i.e., hot in run or start) from the 15A ECM1 fuse in the underhood fuse block. See my post in thread https://chevroletforum.com/forum/s-1...57/#post177128.

two blazers twice the headache

thanks einST but i only have fusible links under hood. i believe fuse box under hood came into existence in the 98. any other ideas would greatly be appreciated.

EinST

My bad, I just assumed. See if the following makes sense, then.

Ignition coil:

Terminal A, PNK wire, ignition voltage, from 20A ECM/Ign fuse 10 in I/P fuse block
Terminal B, WHT wire, tach sig, to IPC terminal 8
Terminal C, WHT/BLK wire, tach sig, from ICM terminal D

ICM:

Terminal A, PNK wire, ignition voltage, from 20A ECM/Ign fuse 10 in I/P fuse block
Terminal B, WHT wire, ignition timing sig, from VCM connector C3, terminal 9
Terminal C, BLK/WHT wire, ground
Terminal D, WHT/BLK wire, tach sig, to ignition coil terminal C

Upstream of the ECM/Ign fuse is the ignition switch and then one of the fusible links.

two blazers twice the headache

thanks for the info i havn't worked on blazer much lately, but i did get it started once but had to shut down right away because had no coolant in it.(i was in the middle of a coolant system flush when i first had no start issue).i noticed cam sensor on back of distributer had a broken wire harness so i fiddled with it and it started. i wanted to see if i had power at coil with this unplugged and i did. plugged back in and now have no start. put a new sensor in and still have no start. i do however have power at coil but no spark out of it.(new coil) do you think i have a bad wire issue from cam sensor to where ever it goes from there?

EinST

If the ignition coil and ICM checked out and yet there was no spark, I'd suspect the CKP sensor or wiring.

CKP sensor:

Terminal A, PNK wire, ignition voltage, from 20A ECM/Ign fuse 10 in I/P fuse block
Terminal B, PPL wire, CKP sens sig, to VCM connector C1, terminal 28
Terminal C, YEL wire, CKP sens rtn, to VCM connector C1, terminal 31