hey guys can anyone give a newbie some advice. Im buying a 97 ram 2500 4x4 8L v 10 from a friend of mine and ran into a problem. the truck was parked about a yr ago and ran fine. he went to start it and the battery was low and while trying to start it he could hear the fuel pump prime. we replaced the battery and now everything has gone haywire now the truck has no spark..fuel pump wont prime and it will not communicate with a snap on scanner..we have checked all fuses and relays we could find and all test out ok. we can maually get the pump to prime via jumping the relay terminals. engine cranks but no spark or fuel.

any thoughts would be much appreciated!

 

Check ASD relay.

 

I think gd nailed it. Swap the ASD relay with the horn relay. Give it a shot.

 

it checked out ok and swapped it with another relay

 

No spark an no fuel sound an awful lot like an asd event...... If you aren't getting fuel pump prime, you aren't getting asd engagement either. (same circuit) Verify POWER at the input side of the asd relay. If you have power there, jump the relay, and see if the truck starts.

 

^^What HeyYou said. Most def have an ASD issue.

 

Hunterx5, You stated that you changed the battery. Did you put a new one in or just another one in. Make sure the ground cable is good and it is clean where it bolts to engine block behind and below AC compressor by PS pump. A bad battery can send one on a wild goose chase, and a bad groung can do the same.

Is it cranking but just won't start? Everything going haywire is pretty vague. The part about the not communicating with PCM maybe not getting 12v or ground to the right places.

 

I don't think the ASD will cause the scanner to not work, but a bad ignition switch would! That would also make the ASD circuit not engage, causing no spark or fuel pump.

 

Been on here for a few months, and I've never heard "ASD" mentioned. What is it because I have a feeling I will need to know...

 

Automatic Shutdown Relay. Provides power to fuel injectors, and coil. PCM will turn it on for three seconds when you first hit the key. After that, shuts it down, UNLESS it sees a signal from the cam/crank sensor that the engine is turning.