Truck Repair: starting problem, throttle position sensor, cam shaft position sensor

Question
my 87 dodge pickup with a 318 will not start when it is warm and humid outside. I have tried a new coil and wires and distribtor cap etc. nothing has solved this problem. could you please give me some advise as to what to check next. thank you

Answer
Hi Steve,
That probably has fuel injection, and thus, you should be able to hear the fuel pump in the tank running. Make sure it is.
If the pump is running, at least for the first three seconds after the key is turned to run, then check for spark.
I would assume that you did check for spark, due to the work you did.
I assume there is no spark.
Wiggling connections is always the first step.
After that, I would look for a crankshaft or cam shaft position sensor.
I have gone through a lot of Dakotas, and Dodge vans, as well as a couple pickups, and the SMEC, or computer, is very dependable, and seldom causes problems, although that is a possibility. I would sure get a scan tool connected for testing, though, before buying one.
You know you can recover any stored fault codes with the ignition key, right? Just turn the key from off-to run-to off-to run-to off-to run. No cranking, and leave it in run. Watch the dash engine lights, and one of them will start to blink. It will blink two digit codes. blink-blink-blink pause, blink blink, long pause, means code 32.
The last code should be 55.
Then search for fault codes to see what it might say.

Search Google for fault codes, diagnostic trouble codes, OBD (on board diagnostics), etc.

It might work to disconnect a sensor, like the throttle position sensor, which should place the engine in a limp-in mode, and set a code, but you would know if it is a closed loop only problem, caused by sensor readings.

Van