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bigwrench3311

2K views 2 replies 3 participants last post by  LATECH 
#1 ·
working on 1993 dodge dakota 3.9L 4x4 auto. no spark ,have 12 volts to coil. changed crk. sensor,cam sync. no help. has 12 volts to f.pump but pump is bad. please help! thanks.
 
#3 ·
Check the basics as the guys have mentioned earlier in the post.

The coil may have power, but you also need to check to see if it has the ground pulse from the PCM to fire the coil.

The coil needs a ground pulse, and it is supplied by the PCM.
Hook your test light clip to the battery positive, then un hook the plug at the coil. Probe the non hot (not the 12 v + side) side of the coil harness, and crank the engine. It should blink as the engine is cranked.
If it does not the PCM is likely the problem.
If it does blink, the the coil must be defective.
The PCM processes the cam and crank signal and triggers the coil and injectors. The PCM could be defective in the output stage to the coil, or the reference voltage section for the cam and crank sensors has failed, and they arent generating a signal for the PCM to use for coil triggering.
 
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