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driving with two feet to keep it runing

660 Views 10 Replies 6 Participants Last post by  moyer_12valve
hopeing someone can help give me some insight to my problem. i have a 97 12v with 281,000 mi. on it and dont know much about diesels. somtimes it idles well and and will suddenly drop and the voltage drops with the rpm's. if i turn on the a/c it will kill it. it also will not start without pressing the accelerator about 20%
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If the voltage drops low enough wont it kill the shutoff solenoid and in turn kill the truck. :confused013:
have you changed the fuel filter? And sounds like your idle needs to be higher
Ya if the batteries are dead.
when it is in neutral it drops to 10 volts from 14 at about 450-500 rpms but most of the time willjump back to about 700 in 5 seconds the does it over and over. i bought a new filter yesterday and plan on changeing it tommarow.
Ok I think the fuel filter will help
i had a 95 12 v it would jump back and forth in rpms and then it got where u would turn the switch off and it would keep running . imo u have a bad fuel shut off solenoid . the voltage jumped around on it to
Idle should be at 800rpm in gear with the AC on.

These things do not like a low idle at all. It will cause the hard starts unless you give it throttle and will cause the stalling you describe.

CumminsDatabase.com :: 12V Idle Adjust

Also, the voltmeter fluctuating is the grid heaters cycling, they draw almost 200amps which the alternator cannot keep up with while they are on!
is there any way for me to test the solinoin or should i just replace it?
The solenoids RARELY are an issue. The boots may break up and cause some dirt to enter it and jam it up but thats an easy fix. also check the solenoid rod length.

The solenoid has 2 coils. One to hold pull up the rod which is energized when the starter is engaged. another coil holds the rod up and is energized with the key on. Usually the only way the solenoid burns up is when the starter contacts stick and cause the high amp pull coil to be energized for a long time.

CumminsDatabase.com :: Fuel Shutdown Solenoid

Get your idle speed fixed first though, its way to low.
mine does this same thing now it has the 4k springs.
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