1998 GMC Sierra Extended Cab will not start?

[Ginger M]

We have a 98 GMC Sierra with a 305. We bought it used in Jan. 2010... It would run for about 5-6 days then not start for 24 hours then it would crank right and run for 5-6 days and etc. We replace the fuel pump and filter, plugs and coil, and even had to replace the intake gasket. Took it to 4 shops (GMC DEALER INCLUDED) and none of them know anything, it does not have any codes. So we could remove coil wire 1 and it would start replace the wire and it would run. Well now it will turn over but not start. And the mechanics have looked and still no codes... ANY IDEAS other than a smart a** one would be great... THANKS IN ADVACE
its been towed while it was not running, and it is not running now and still no codes. there is no fire at the plugs!

 

[Molson02536]

We have a 98 GMC Sierra with a 305. We bought it used in Jan. 2010... It would run for about 5-6 days then not start for 24 hours then it would crank right and run for 5-6 days and etc. We replace the fuel pump and filter, plugs and coil, and even had to replace the intake gasket. Took it to 4 shops (GMC DEALER INCLUDED) and none of them know anything, it does not have any codes. So we could remove coil wire 1 and it would start replace the wire and it would run. Well now it will turn over but not start. And the mechanics have looked and still no codes... ANY IDEAS other than a smart a** one would be great... THANKS IN ADVACE
its been towed while it was not running, and it is not running now and still no codes. there is no fire at the plugs!

Replace your ICM (Ignition control module), It sounds like there is where your going to find your issue that is causing your sierra from starting. Ignition control modules were introduced along with fuel injection. Electronic fuel injection requires a computer coupled with a host of sensors for situational input from the engine to operational strategies compiled within the computer.

The ignition control module receives power from the ignition switch on one terminal and has a ground terminal for ECM to ICM control of the ground signal. There are ground wires to all coils so they can be fired individually. On this type of system, each coil fires two spark plugs simultaneously. One spark is useful, and the other is not. The wasted spark usually fires on the exhaust stroke.

Ignition control modules have been known to go bad on all makes and models of vehicles. When this occurs, there is no spark or a very erratic spark. It is easy to diagnose if this should happen. Use a voltmeter to check for power at the control module. The ignition should be on while checking for power. If there is power, check for a pulsating ground at the module while cranking the engine. This signal is from the computer. If there is a signal, the module is bad. If there is no signal, the computer has an issue with a sensor or itself.

The other way is if you have a second car, you can remove the ICM and have it tested at Auto Zone, Parts Source. They test ICM free of charge, good luck and keep us posted.