crankshaft position sensor problem

[Jayford]

well its been almost half a week now and its driving me crazy. i have swapped from a 2.3 to a 4.0 and still can't get it to start. the engine is from a 1994 and my truck is a 95. i have used a wiring harness from an 95 and the computer is from a 98 which works fine. the only problem is it wont fire. when we have a computer on monitor mode everything works properly except when it turns over it shows the engine rpm for a couple of seconds and then goes back to 0 while it is still turning over. i have put in a camshaft position sensor and still the same thing. it is getting fuel, the spark is the only thing it lacks. all the wires have been checked, any help or thought would be greatly appreciated, thank you

 

[Bird]

The camshaft position sensor has nothing to do with the ignition - it's for the fuel injection. The crankshaft position sensor (front of engine - down by balancer) is what you need to look at.

Bird

 

[abrush]

Make sure you didn't miss any grounds. I did that on my swap and it took me weeks to figure it out. Just forgetting to hook up one ground caused my vehicle to get no spark therefore it wouldn't start.

 

[woodyedmiston]

More to the point on grounding your truck. There should be a direct ground from the block to the firewall on most Rangers - usually a braided wire. Runs from a bolt on the back of the left cylinder head to a stud on the dash where the other electronics are grounded. Since you changed engines this might have been overlooked. Pop the hood on a V6 Ranger and you'll see what I mean.