No matter with the SMARTY on or back to stock, when I rev the engine up, the rpms hang up for couple seconds, then come back down slowly spittin and sputtering. The throttle is not smooth when coming down. I have no starting problem, no smoke at idle just a slight miss or vibration at idle. The truck runs great. Any ideas

 

Hey, i've had that happen a few times to, but my truck was programmed. Never had it happen stock, kinda of scary. Not sure what causes it and you are not the only one.

 

The pressure bleeding off that is left into the lines.. very common in Common rail trucks. The excess pressure has nowhere to go so it just bleeds off into the cylinder causing it to hang a few extra seconds. Or at least thats how it's been explained to me. Kinda nice when sled pulling you don't have to play with the throttle to keep the turbo from barking the engine kinda does it for you and slowly comes back down.

 

no no no. its your injectors. my truck did the same thing. no codes no symptons. just a intermittent vibration at 1800 rpm in high gear or under load. a injector stuck open and melted a piston and wrecked head. now im forking over $15,000 for a new engine.

anyways i heard lots of trucks before and none drop rpms like yours and mine do. after i melted piston (didnt know at first) i stuck 6 new injectors in and idled engine. it reved normally and didnt hang up anymore.

 

Now i am wanting to sell my Smarty Jr, you have got me paranoid, lol.

 

mine did it stock also. everyone says its the chips doing it. well guess what? it isnt. my edge juice just does timing and duration not pressure. and second truck did it when edge was tooken out. also did it before i put edge juice in.in 2 weeks when i get my truck back with new engine ill have lotsa info for yous.

 

i can report on my new egts, new injectors, new LP etc....

 

My truck has only done it twice, and thats when i was winding it out through the gears. How many miles did you have on truck when the motor decided to melt? Also, are you saying we have injector problems and should be checked out? Because i dang sure don't want to fry my motor at 104,000 miles.

 

not saying you do?i had 215000 km on mine when #1 piston melted.just that tons of people are saying the idle drop down is the nature of the neast...wrong! test drive a ford 6.0,duramax 6.6 , 6.7 and 5.9 cummins new from factory. they dont do this. try a friend or relatives 5.9 common rail. i bet 30% only do it. doesnt mean ur injectors will go in a week. you could go 5 more years like this

 

Thanks for the info sallyman1, is there any way the injectors can be tested without pulling them out.

 

I have had it happen only when Smarty is on and rowing gears at wot and not even letting off fuel. RP gets so high, then when you let off, it has nowhere else to go. Didn't like it. That's only experience I've had with it, a buddy was with me a Cat diesel mech. and CTD common rail nut, that's the way he explained it to me and looking at my Rail Pressure, IMO he was right.

 

So, you are talking about rail pressure, not injectors, right?

 

nelrod. what u r saying makes sense and thats what i thought. but try other peoples trucks with and without chips/programmers. 70% of them act normal. 30% act like mine did. no one can explain why. test drive a brand new 6.7L if u want and try it. It wont do it.

 

So, do I have to pull the injectors to see if there bad

 

one way. otherway is too hook it up to a drb scanner. they can measure them electronically. they can also flow test. all this will cost $$$ but itll be worth it. also my injectors tested 98% on scanner and i still had the rev down problem???