What additional draw is place on the asd circuit when you put the truck in gear?

If you just let it sit and idle, does it still blow the fuse?

 

just for the hell of it i went out there today car hasn't ran since yesterday i pulled out the 40 amp fuse i shoved in place of the 30 amp fuse just to move it so i could park the darn thing put another 30 amp fuse in expecting it to blow but it started right up let it run for like 5 minutes then put it in gear didn't blow the fuse so what ever is going with this thing is only doing it after its fully warmed up, it was only having problems after i let it sit for like 20 to 45 minutes after i drove it but now its starting to do it before i even shut it off i know the fuel pump has never been replaced in this truck because i bought it from the original owner he said he never had the injectors replaced or the fuel pump i replaced the injectors because it had a few bad ones but not the pump.

 

So this is a 4.7L. So the ASD relay drives all 8 coils, all 8 injectors, the fuel pump, ....I think that's it? Unless you have a wire chaffing somewhere

 

yep its a 4.7 and i only have problems after i drive it with it not wanting to start all the relays are good we ohm ed the injectors they are fine so are the coils yesterday was the first time it popped the asd fuse over and over motor was still hot though thats why i put a 40 amp fuse in it to see if it would stay running so i could move it and it did left it sit over night put a 30 amp in just to see if it would start and it did also able to drive it no codes come up or anything ????????

 

Did you ohm the coils hot? A shorting primary side will pop the ASD supply fuse. The windings in the primary side can test fine cold, but as soon as the coil gets hot, the enamel coating can start to melt and he windings can short out. cools off, enamel hardens back up.

On paper it could even ohm out fine and only be arcing with 12 volts applied.

But hypothetically, that would make a coil driver fault code and/or a misfire code.

 

thats what my brother asked me if i did see hes used to working on what i call newer stuff im used to older mopars the newest stuff im used to working on are jeeps with 4.0l in them when i seen this 4.7 i was like is this, and nope i just ohm ed the coils cold same with the injectors he said those bosh aftermarket injectors like to really spike when their hot.

 

i don't know if i mentioned this it didn't happen at all with the stock injectors but one injector was bad and 4 were swollen and cracked that's why i replaced them and a lot of people were telling me to replace the stock injectors with the bosh 4 hole injectors

 

well i let it warm up today to check the coils and fuel injectors when warm the truck got to 175 degrees and shut off this time the check engine light came on with the code P1389 no auto shut down something at power train control module

 

i took the computer out today to see if i could smell or see anything burnt, the pins were fine none of the connectors were melted i wonder if it just went because it was 18 years old or if it was caused by a short somewhere because why would the 30 amp asd fuse keep popping after it warmed up i put new plugs, new coils' new injectors in this sucker so i replaced almost everything that ties into the asd fuse oh yeah i forgot the alternator was making some funny noise the first day the asd fuse blew my friend and i look at each other with a puzzled look on our faces

 

Now we have some information. P1389 says it's not the PCM's fault. The ASD circuit is failing on it's own. The alternator does not go through the ASD relay. You need to figure out what is shorting out when hot.
If you replace the fuse, does it re-start?