Intermittant no start 98 Blazer

[lxman1]

Hi, I am working on a 98 Blazer 4x4 4.3L. It has intermittant start problems. Usually after sitting. It is not a fuel pump problem, I have replaced it and have over 60PSI. In a no start situation, it has no spark. It will spark once or twice when first turning it over, then no spark. The coil Ohms out the same when it will and will not run. I am thinking ignition module, but the local auto parts stores can not test mine and I do not want to spend $80 if this is not the problem. It always has 12V to the coil whether it has spark or not, so I don't think that the ignition switch is the problem either.
Any more ideas? It runs perfect once it starts and may sometimes start the rest of the day, and sometimes it won't.

Jimmy

[MT-2500]

I would start with a crank sensor check.
Any codes?
Is the VCM/PCM getting a rpm signal on a no start?
Have you checked fuel pressure on a no start?

[lxman1]

Well, I went ahead and swapped out the ignition module last night. I'll know this afternoon if that worked or not. I haven't checked the crank sensor. I'm not sure what wire at the VCM that I would use to check for a rpm signal. This is a friends vehicle and I do not have a manual for it.
The fuel pump is a couple of months old and it has between 63-65lbs as soon as I turn the key on. So that rules out the pump.

[MT-2500]

Good luck and let us know how it goes.
Hard start or no start cold points to fuel pressure.
Always check fuel pressure when no sart.
And check for injector pulse on a no start.
To check The crankshaft sensor signal or a true test on it you need a lab scope.
Or a scanner that will read out the rpm signal.