Hope someone can help me out here. I am mechanically inclined...
My son has a '98 S Blazer with the 4.3 liter. Last evening he left the house and was back in 10 minutes on the end of a tow rope. He told me he noticed the voltmeter heading toward discharge and before he could get the vehicle home, the engine died. Now, 5 months ago it exhibited the very same symptom, except when it quit the battery was indeed depleted. Turned out the alternator failed, which I diagnosed and replaced with a reman Carquest unit. Since he thought it was the same dilema, he did not try to restart it and had a friend tow him home.
As soon as the vehicle came home last night (it was raining), I hit the key and noticed an approximate indicated 12 volts on the gauge. Further, the engine cranked fine and with good speed. The battery was still up. It cranks very well, but nary a hiccup toward firing at all.
I quit cranking, opened the door, and turned the key to "on". I could hear the fuel pump cycle in the tank. I popped the hood and removed the cap on the Schrader valve on the fuel line, pressed the valve core, and had fuel pressure evident. I definitely have at least some pressure. At that point I figured I had an electrical issue. I removed the underhood fuse panel cover and with my Fluke digital volt/ohm meter checked every fuse. All good. Then I checked every fuse under the panel cover on the left hand dash. All good. I pulled the fuel pump relay and replaced it with another similar in the underhood fuse block (there are several in there, all the same part number....just swapped) Still, no start, cranks fine. With that, since it began to rain hard, I left it until this morning.
Today I pulled the coil high tension lead out of the distributor cap and spark gapped it to a stud ground. While my wife cranked the engine, I had a nice heavy spark jump from the lead to the ground. The coil is putting juice to the distributor. I then removed the cap and rotor. Some buildup was on the cap terminals as well as the rotor lug, so I cleaned all that off. Replaced the cap and rotor and plugged all the wires and coil back in. Hit the key, cranked very well, no sign of firing.
Headscratching. My experience tells me I have fuel and spark and presume the compression is fine (24,000 miles ONLY on the vehicle).
I then think maybe I don't have fuel afterall. I pulled the dipstick and there is no smell of raw gasoline in the crankcase. I pulled the cover over the throttle body and while my son cranked the engine, I squirted raw gas down into the plenum. No firing at all. I most definitely am applying fuel direct to the intake.
I then pulled the most forward lefthand (drivers side) spark plug wire from the plug and put a new plug in the wire, grounded it to the exhaust manifold and had my son crank the engine. I watched a nice blue spark leave the plug electrode each time that lead was told to do so.
Not sure what else to do, I disconnected the battery for a minute and reconnected. I hooked up a battery charger and brought the battery up to a full 13.4 volts surface voltage. I then tried cranking the engine for about 15 seconds. Still, not a single hint of firing.
Here I sit. I am not sure what to do next. I don't have a manual and there is no dealer here in this small Arctic rural town where I live. Sorry for the long post, but I wanted to spell out everything I have tried to do.
I would very much like to hear from you folks and hopefully this is something someone else has experienced and can shed some light on. Anything you can offer would be greatly appreciated.
You may email me direct at home if you wish. I could use some help!