First, before you spend any money anywhere else, take the battery to a car parts store and have them check it. A bad cell in the battery will cause a NOBUS NOFUSE message, and you won't even be able to jump start it. In fact, I had trouble removing the key.

 

Along with the battery, check all of the grounds.

 

Thanks for your answer in this thread. So if after that reset process it still says nobus it is more than likely a connection or a bad ECU? I have just done a 3.9 to a 5.2 conversion and ran the wires for the #7 and #9 injectors according to what I read on this forum, which also said I didn't have to have the computer flashed. Is that correct or could it also be that? Thanks

 

I hope it's OK that I piggy back on this thread. This morning I had the NO BUS issue. The wipers did not work, all the dummy lights were on BUT the speedometer worked and the vehicle ran. I made the short commuted to work, on the way I turned the vehicle off once to see if the bus would reconnected-- and I then lost the speedometer. After work, everything was back to normal. I just got done d/cing the battery, cleaning the terminals, d/cing the PCM and cleaning all the connectors with electrical connection clean. I plugged them in and out repeatedly and rinsed them again with the cleaner.

I then walked away and let things dry why I sprayed the yellow sedge popping up in the back yard. 20 minutes later, I put some dialectic grease into the PCM connectors and reconnected them, and a little on the battery posts and reconnected the battery. Everything seem to be fine at the moment, and I did clear up the gas cap code in the process. There were zero signs of corrosion on the PCM so I am not sure what is going on or if this will crop up again.

 

This morning the no bus, no wipers issue this morning popped back up. Everything was good, but after driving a block the message came up. Scan tool will not connect. That is all I had time to try.

 

Did you use the 5.2 PCM with the swap?

 

No because the 5.2 came out of a jeep. It has been a good challenge because I've always been a Chevy guy. Also could that sensor under the battery have anything to do with this issue? I put a smaller battery in the 1999 Ram 1500 also.

 

Nah, that's just a battery temp sensor. It can cause charging issues, but, not starting issues.

 

I am still trying to figure out this whole ecm deal. I can't remember where I read that I wouldn't need a different ECM or reflashing to go from a 6 to an 8 . Does anyone know if I do? Same kind of trans back in. This 318 and trans came out of a 4wd jeep so I can't use that one. Would the chrysler jeep sensors be too much different for this to jell? Even after checking all the grounds on engine body and ECM, cleaning the connections at ECM, disconnecting and charging the battery I still get a NO BUS. AND I hate to admit that the engine and hoodless truck sat unprotected besides the holes, so there is corrosion on all aluminum parts. Thanks in advance

 

Your PCM will need to be programmed for a V-8, otherwise, it won't know what to do with those other two cylinders.

Need to figger out the no bus problem....