1987 b250 no start

[ivandrocco]

Any idea what would allow cranking and downstream power, but cut power to the dash gauges and prevent a start?

From what I've read, could be ASD or isolator failure. Only reading 7v across the secondary battery terminals regardless of how the isolator switch is positioned.

[BBQ]

Originally Posted by ivandrocco

Any idea what would allow cranking and downstream power, but cut power to the dash gauges and prevent a start?

From what I've read, could be ASD or isolator failure. Only reading 7v across the secondary battery terminals regardless of how the isolator switch is positioned.

You have a dead battery?

[ivandrocco]

...on Jumpers. I think it's a faulty isolator or ASD?

[booster]

Originally Posted by ivandrocco

Any idea what would allow cranking and downstream power, but cut power to the dash gauges and prevent a start?

From what I've read, could be ASD or isolator failure. Only reading 7v across the secondary battery terminals regardless of how the isolator switch is positioned.

Depending on how they have it wired, it could be the ignition switch not connecting in the "start" position to the dash and ignition systems. When this happens (at least with carburetor vehicles), some will actually start if you crank them for a bit then let off the key to the run position. They will then have enough fuel and momentum to fire when the run position gives spark.

[Johnny R]

How about a problem with the the Ignition control module.