96 3.3 starts for 10 seconds

[rramey0214]

1996 Caravan with a 3.3 starts up and runs for 5-10 seconds then quits. Changed all the autoshutdown and fuel pump relays. Computer changed - wouldn't start at all before then. Fuel pump stays on. Won't start at all if Cam or Crank sensors are disconnected, so we suspect they are OK. They both get 8 volts. Spark appears to be fine till it stops running. Battery voltage OK. This is making us crazy. Anyone seen this before??

[Scotty89]

The last time i seen this it was the key. If theres a chip in the key it may of gone bad. Try a different set of keys and see if they do the same thing. Some vehicles have a valet key. It allows the car to run so long then shut off.

[coalminer]

Originally Posted by rramey0214

1996 Caravan with a 3.3 starts up and runs for 5-10 seconds then quits. Changed all the autoshutdown and fuel pump relays. Computer changed - wouldn't start at all before then. Fuel pump stays on. Won't start at all if Cam or Crank sensors are disconnected, so we suspect they are OK. They both get 8 volts. Spark appears to be fine till it stops running. Battery voltage OK. This is making us crazy. Anyone seen this before??

Im going to throw my 2 cents worth in on this, as my brother had an Intrepid with a 3.3 that was doing something similar. After it starts, watch the coil pack, when his would start, you would see a spark from the coil pack to the engine and it would stall and not start again until the battery was disconnected. At first we didnt see the spark, but we could hear it, took about 20 times before we seen the spark and replaced the coil pack, and it ran fine after that. Worth a try!!!

[rramey0214]

Scotty and Coalminer,

Thanks for the suggestions. My brother and I are trying to fix this for a young family man with no money. He was told that the computer (ECU) was bad, so he went to a junk yard and traded his old one for another. It wouldn't start. We had place we trust send us another computer and after changing the coil pack it started running for 5 seconds then quitting. Someone told us that in 96 they had some Caravans with Anti-theft (chip in key) and some without, but this one doesn't. But the computer may think it does and without the "OK" input will shut the engine off. I've seen another engine do that if it does not recognize the key.
Our trusted computer place did some checking on the van's VIN and saw that the computer he gave us was for a 3.8L V6 engine - so we're getting another one. But if anyone has any other ideas, I'm happy to hear 'em.