My dad called me this weekend to help him get my brothers jimmy cranked, 1996 GMC Jimmy with 4.3 liter.

Long story short there is no spark from the coil, I tried a coil/ign. module (little black box that is mounted beside the coil) from my tahoe and it didn't spark either, but the one off the jimmy cranked my tahoe.

I checked the red wire (I think) the haynes book says to check on of the wires that go to the coil with the key on and it was hot with the key on.
The only other thing I did was check to make sure the sensor on the bottom of the timing chain cover was plugged in, I assume thats the crankshaft sensor.

Other then replacing the computer what can I do/check????????????????
Because I didn't put the motor in I don't know for sure that there isn't somthing unplugged or missing.

Also the wires that go to the front clip where cut and spliced back together, I don't know where they go, but theres more wires there then just blinkers and headlights.


I forgot to say that the engine has been removed and rebuilt.
This is the first time we have tried to crank it.

My dad called me this weekend to help him get my brothers jimmy cranked, 1996 GMC Jimmy with 4.3 liter.

Long story short there is no spark from the coil, I tried a coil/ign. module (little black box that is mounted beside the coil) from my tahoe and it didn't spark either, but the one off the jimmy cranked my tahoe.

I checked the red wire (I think) the haynes book says to check on of the wires that go to the coil with the key on and it was hot with the key on.
The only other thing I did was check to make sure the sensor on the bottom of the timing chain cover was plugged in, I assume thats the crankshaft sensor.

Other then replacing the computer what can I do/check????????????????
Because I didn't put the motor in I don't know for sure that there isn't somthing unplugged or missing.

Also the wires that go to the front clip where cut and spliced back together, I don't know where they go, but theres more wires there then just blinkers and headlights.


I forgot to say that the engine has been removed and rebuilt.
This is the first time we have tried to crank it.

Check all fuse and wiring and plugin.
Make sure the dist wires are pluged in and the pins where in disrt where pligin gors are not bent over.
Does coil have 12 volts to positive side?

With key on or engine can you hear fuel pump run?

Yes, I have good fuel pressure, but straight from the coil there is no spark. The hot wire is hot but no spark from the coil. This is the newer ign. system with the coil mounted on the front right side of the engine with the ign module mounted beside it.

Yes, I have good fuel pressure, but straight from the coil there is no spark. The hot wire is hot but no spark from the coil. This is the newer ign. system with the coil mounted on the front right side of the engine with the ign module mounted beside it.

Is dist shaft and rotor turning when you crank engine?
Is dist side wires pluged in?

I went and worked on it this weekend and had no luck with anything I tried.
This is what I found,
The hot wire is hot on the coil.
There are no codes with an obd computer.
There are no fuses that I can find that are blown, however I can't find any fuses under the hood.
I checked the plug in the back of the dist., and the crank shaft sensor plug, both are good and don't have bent prongs
I removed the crank shaft sensor and the reluctor wheel was reinstalled.
I checked the motor and with a continuity tester and its grounded, and the ground is installed properly.

The problem is the engine won't start the fuel pump comes on fine and there is fuel pressure.
But NO Spark from the coil. I put the coil/ign module on my tahoe and it worked fine...

I understand that with no crankshaft sensor there is no fuel?? If this is the case, will the fuel pump not work,
or the injectors won't work??

So is there anything else left check before aimlessly changing parts?????

And if not what should I change first the crank shaft sensor? Then what the computer, or dist. sensor???

I went and worked on it this weekend and had no luck with anything I tried.
This is what I found,
The hot wire is hot on the coil.
There are no codes with an obd computer.
There are no fuses that I can find that are blown, however I can't find any fuses under the hood.
I checked the plug in the back of the dist., and the crank shaft sensor plug, both are good and don't have bent prongs
I removed the crank shaft sensor and the reluctor wheel was reinstalled.
I checked the motor and with a continuity tester and its grounded, and the ground is installed properly.

The problem is the engine won't start the fuel pump comes on fine and there is fuel pressure.
But NO Spark from the coil. I put the coil/ign module on my tahoe and it worked fine...

I understand that with no crankshaft sensor there is no fuel?? If this is the case, will the fuel pump not work,
or the injectors won't work??

So is there anything else left check before aimlessly changing parts?????

And if not what should I change first the crank shaft sensor? Then what the computer, or dist. sensor???

Is the dist shaft/rotor turning?

Does fuel pump run engine cranking?

Will your scanner read out RPM signal cranking engine?

If you are switching parts switch out ign coil.

On the dist side wire plugin pull plugin and take a mirrow and check the little pins in dist for being bent over to side.

The crankshaft sensor has to send a crank/rpm signal to the computer for the ign to spark coil.
You need a scanner to check for rpm/crank signal.
No crank signal and the fuel fump will not run engine cranking.

The crankshaft sensor has to send a crank/rpm signal to the computer for the ign to spark coil.
You need a scanner to check for rpm/crank signal.
No crank signal and the fuel fump will not run engine cranking.

When you say scanner are you talking about an OBD?
I usually rent one from autozone, I have only read codes with it, but there are other functions that I haven't played with.
Is an OBD "computer" such as the one rentable from autozone what you are refering to when you say "scanner to check rpm/crank signal"?

When you say scanner are you talking about an OBD?
I usually rent one from autozone, I have only read codes with it, but there are other functions that I haven't played with.
Is an OBD "computer" such as the one rentable from autozone what you are refering to when you say "scanner to check rpm/crank signal"?

Yes it should show that and also pick up a code if it is no working