Nascar

Am I missing something? This is a 12v engine according to the forum & fuel pressure. Injectors popping off early will not create a fuel knock, as it is same as advancing the inj timing but at a lower pop pressure ( less atomization, which only causes a dirtier burn & less power & less mpg ). And no way that I know of to test live data on a all mechanical 12v ? As mentioned, one or more of the inj's are dribbling (leaking down way out of the regular compression stroke) is most likely the cause of the fuel knock.

Your fuel pressure is low. You should have min 19-22 at idle & min 25-32 under load. As for your knock....most likely inj's as army-grey wolf mentioned. When a injector(s) seat area gets worn or dirty, the nozzle can start dribbling ( usual cause of a fuel knock ) or spraying outside the piston bowl ( which can cause cylinder wash down....damages the rings, hard on the piston(s) & will cause excessive blow by over time ) or both.

Thanks guys. No aftermarket anything but a trailer brake controller. All other lights in dash come on everytime, just a crap shoot for the WTS light, no matter what the outside or engine temp is. Will attempt to try using meter. Don't like the sounds of a possible ECM issue but as mentioned I will try drain 1st. Yes, both batteries were replaced together. Same lot & age. Thanks

Hi Guys. I have a ton of mechanical experience but very weak in electrical. I hate it. Bought a 1999 Cummins for my daughter that will be turning 16 in Sept ( she will be paying me back for the truck, lol ) and even with new batteries, if it sits for a week or more, the batteries drain to the point it will not start. I have tried to research this problem & have eliminated the seat belt modules are not the problem. What else could it be ? Any help would be much appreciated. On a side not, it also does what I think is a weird thing. Sometimes when you turn the key to the on position, the wait to start light doesn't come on & no matter how long you crank, it will not fire. I know the ambient/engine temp sensor monitors this but if you turn key off & then back to on, the wait to start light usually comes on & once it goes off, it fires up right away. again even with engine warm, if the wait to start light doesn't come on even for 1 sec, you can crank to the cows come home & it will never fire up. Just thought I would throw that in here, incase it has something to do with battery drain ? Other than that, everything else works as should. Thanks

Backfire in a Cummins is usually late timing ( retarded timing for fuel amount ). The more fuel one has the more timing you need to burn said fuel. Fuel is burning after cyl & may be burning even after turbo.