For the past few months my truck has developed an issue with random long starting and everytime I am coming to a stop and put the truck in neutral it drops down to around 700rpms then levels back up at 800 or so. No codes. Just replaced the fuel filter. I sold my 99' cause it had a 53 block and now it looks like I am into big problems again. Whole reason I love Cummins is because of our 1990 W250 having close to 300,000 and never have touched the motor. Just hoping maybe its not an injector. Thanks for the help

 

What kind of rail pressure are you seeing?

 

Don't have any gauges, all stock except for cold air intake and straight pipe

 

anybody? anybody?

 

I'm not really a common rail specialist, but thought I'd throw in my 2 cents here. While long crank times are a symptom of a bad injector, your idle undershoot makes me wonder if it could be a fuel control actuator that is acting up. Its job is to control rail pressure and if it starts to fail, one of the symptoms is surging at idle. Maybe when yours drops down to idle, your FCA can't react fast enough to return to the idle smoothly, therefore you get the little stumble before it recovers and controls the idle. Just a thought, hopefully somebody else can chime in here.

 

You can check the injectors w/o having to pull them. All you need is an ohm meter w/ a fine read. Unplug and check the head side of the connections, one at a time. I believe the connections are vertical to each other for the one injector connection.

 

Dosen't sound like an injector issue. Run some 2 stroke oil in it, if the idle drop goes away it is the FCA.

 

check your FCA

my dads 05 had same issues plus it would shut off at stop signs... changed FCA solved problem then, but it did throw a code..

also test injectors, if they are over 100k it wouldnt hurt to check them... and run a two micron filtration if you dont have it.. GDP makes a slick lil kit that goes under hood...

 

What is the FCA? Glad to hear it might not be an injector. I just put Standadyne Performance in it to see if that might help and it seemed to help the starting but didn't take care of the idle drop when i push the clutch in when slowing down.

 

Going to Cummins tomorrow to get a new Fuel Control Actuator to see if it does the trick. I pray that replacing the FCA will take care of what is going on with my truck.

 

i sold my 01 for the same reason and along with the VP$$ issues.

wish i had keep it, cheaper to repair then one of these when the injectors go out.

good choice on changing the FAC first, I'd do the same thing.

if that does not fix it remove 6 injectors and have authorised Bosch dealer check them, the ohm test only test the coil, there is more to it than that.

 

Well changed the FCA and as far as i can tell it did not help at all with the rpm drop below idle then coming back up to normal when I push in the clutch coming to a stop. Don't know yet whether or not it helped with the pro-longed starts because the starting issue is completely random as far as I can tell. Hasn't ever been hard to start after it sits for a night or a few days.

 

Sounds like the APPS to me
blacksmoke

 

Could you go into detail about the APPS?

 

Would I need to unhook the battery cables to reset anything when i changed the FCA? By the way the truck only does the droping down below idle then back up to normal thing when I'm driving it shifting down or going into neutral while driving. Won't do it just sitting still in neutral reving on it.