No start condition with a Chevy van (or truck)?

[zuren]

Just looking to pick some brains here on the forum. My g/f and I were 2 hrs. from home this weekend for a wedding and we decided to camp the first night up there so we took the van and it ended up dying. I'm back home in the Boston area. Since I didn't have the tools or time to keep working on it, I had it towed to a garage this morning.

The van drove fine up there on Weds. and running errands up until Thurs. afternoon. That afternoon after a 1.5 hr. road trip, the airbag light flashed after restarting it; thought it was strange but it went out after a few flashes. The next morning after sleeping inside, I unlocked the side door manually (after locking the entire van with the remote) and stepped out to use the restroom. I closed the door behind me and I when I returned, the van was locked again with the keys inside. I thought maybe it was a security feature but I could not recreate the "self locking" so that should not have happened. I had a window open so I was able to get inside. After that, it took 2 attempts to start it but it started. It was very unusual; this van always starts on the first turn of the key. It ran fine for a mile and once I turned it off, I was never able to get it restarted. Considering the "strange" events immediately leading up to it being dead, I'm wondering if it is something with the computer.

It turns over strong. Starter and starting battery seem fine. Since it was easy to access, I tried replacing the crankshaft sensor - no change. I also checked the computer harnesses and EVERY single fuse - no luck. Even a shot of starter fluid didn't get it to sputter. Fuel, oil and battery conditions are fine. Spark plug wires and plugs are new within the last 1000 miles. Ignition switch was replaced last winter. Disconnected the battery to allow the computer to "reset" - no change. You can hear the fuel pump prime. No codes or check engine light appear. The spark seemed weak (checked for arc) and thought I should have been smelling more fuel for as many times as I tried to start it.

It's a mute point now but I'm trying to prepare myself for what it could be. Any similar experiences?

 

[HenryJ]

Check the fuel pressure. Pump failures are very common. Less so in later models.
Check the battery connections. They can show correct voltage and still have resistance resulting in reduced amperage. Check fuses with a multimeter. There have been some cheap fuses around that look good, but are not.

Early two thousand model GM vehicles had a problem with brittle wiring. This wire had fewer strands and is less flexible. They tend to fracture internally. As they are heated they can separate and create an intermittent failure. A no start condition can exist when the yellow wire approximately 6" from the throttle body separates. Check the wiring . Pulling each wire can reveal separations internally and dimpled insulation at the break. You can repair the wires with some solder and heat shrink. The dealers fix is harness replacement.

Usually the symptoms are reduced engine power mode. Erratic operation may also be an indicator.

 

[r_w]

WRT fuel pressure, also check the pressure regulator. Cheap part known to fail regularly.

Self-relocking is a "feature" on some cars, don't know if it was on chevy vans--if you manually unlock the driver's door without the keys in the ignition, it will relock thinking you forgot. Hal being helpful...

 

[zuren]

Update:

The garage has had it for 2 days so I decided to call and get an update. The garage couldn't figure it out so they had a tech from the GM dealership come over. They think they now have it traced to the signal associated with the crank sensor (something I suspected) but not sure how or why it is faulty. I hope to know more tomorrow.

Thanks for the suggestions thus far.