1996 Blazer LS no crank, no start
 

I am hoping someone can help out. I am about to kick my blazer off the nearest cliff.

A little history. It was running a little rough and I changed the ignition module, and put in a new distributor. I changed out the fuel filter at the same time. All looked good for several days.

On the freeway it suddenly died. It would crank but not start. After the tow home I changed the crank sensor. It started and ran fine. I drove it for several miles and as I was pulling back into the driveway it started running a little rough. I left it for the day and thought I would check the fuel pressure.

The next day I hooked up the pressure gauge and attempted to start up. All of the lights came on and the fuel pump started, but the starter would not crank.

I checked all of the fuses, relays and fusible links. All were fine. I opened up the steering column and checked the ignition switch. I had a nice strong voltage when the key was moved to the crank position.

I attempted to pull the starter, What a pain. I ended up bench testing the starter in place. No problem. The starter works fine.

Finally, in desperation I ran a new wire from the steering column to the starter and changed the battery cables. Now it cranks over. Just like before all of the day lights up and there is power every where.

However, now I do not hear the fuel pump and there is no power to the
ignition module or coil. Double checked all of the fuses etc. All are good.

BTW it is a V6 Vortex engine

Anyone have an idea of where the problem could be ?

Thanks in advance

Bruce

With regard to the crankshaft position sensor: If or when the sensor, and or timing cover is moved, removed, replaced, or disturbed in any way, the crankshaft position sensor relearn MUST be performed. This is mandatory, not optional. The engine will start and run, but the ignition and injector timing will be incorrect. This will make diagnosis of other problems more difficult, and in some cases impossible. The relearn requires a scan tool that is capable of initiating it, (the el cheapo $500 jobbies at the auto parts stores are not capable).


The starter circuit goes from the ignition switch, through the neutral safety switch on the transmission, then through a relay in the underhood fuse panel, then to the starter solenoid on the starter. From the relay to the solenoid, the wire is purple.


No voltage to ignition coil & module: Both receive voltage from the ECM/IGN, Fuse #10, 20 amp fuse, in the instrument panel fuse panel. The fuel injectors are fed from the same fuse, (pink wire), so check each pink wire at the injector connector with the ignition in the run position. Post your results.

thanks for the info.
I forgot to mention that I changed the Clutch Safety switch.

then through a relay in the underhood fuse panel - 1996 blazer there is no underhood fuse panel. At least I cannot find it. I found some information that the 1995 and 1996 models did not have them.
I do have 3 relays under the hood on the firewall. I pulled them and verified that I do have power to the relays and the relays tested fine.


No voltage to ignition coil & module: Both receive voltage from the ECM/IGN, Fuse #10, 20 amp fuse, in the instrument panel fuse panel.


I pulled the fuse and I have power there.


The fuel injectors are fed from the same fuse, (pink wire), so check each pink wire at the injector connector with the ignition in the run position. Post your results.


I pulled the connectors and checked and I now have power. Dag blast it !!! I had no power previously but now I have power and I have spark !!. I hate intermittent problems. Maybe the connections were dirty ? or could I have an intermittent short in the harness ?


At any rate, so far so good. I have power and spark. However, the fuel pump is not firing up so I am still needing your expert help.


Thanks
Bruce

In the future, don't remove the fuse from the fuse panel. Connect the ground probe to a good chassis ground, touch the positive probe to each terminal on the fuse. Checking them like this checks for voltage and checks the fuse too:


https://blazerforum.com/forum/attach...ine=1454977739


Intermittent problems can be tricky to pin down ;)