duallydave

hi all,just raved up and down on how much i liked the b-d 130hp injectors.went for a long drive today,some hiway,some slow drivin looking at houses,anyway comming into town at the lite i noticed a miss,sounded real smooth then theres a stumble,can see it in the tach too.doesnt do it all the time,seems more promonent when i give her throttle and let it come back down to idle.got home and checked all fuel lines,no leaks,snugged em up again.if i didnt torque the injector hold downs rite would it cause this?or maybe the orings on the conector tubes,maybe she just needs more break in time.anyone else heard of this?maybe its getting to much fuel at idle and flooding itself a bit?no smoke though,any thoughts????

600 Megawatts

What you are describing, I would say, is normal with 130 Hp injectors. The injection pump and computer know approximately what pulse to give a stock injector to idle at the proper RPM, and then it adjusts the idle pulses up or down slightly as required. But now you have much much larger injectors and so the approximate pulse that used to give the correct idle is now too big, and so it must correct, and then even the slight correction it makes is usually too large... The result is a bit of an overshoot in RPM, either up or down depending on what is going on... A way to test this is to turn on the AC with the truck idling in the driveway... now with your big sticks when the AC compressor turns on and off you will notice the truck bark a bit more than it used to to jump back on RPM and then it might hunt a bit until it settles out. You will really notice this when letting off of the go pedal really fast. You will also notice the cruise control tends to hunt a bit as well, for the exact same reasons as described above.

With really really big injectors, like the sled pulling guys run, the trucks idle is in a constant swing, a lope if you will, that a lot of people attest to the cam, but the most of it is the idle circuit hunting...


Kevin

duallydave

rite on,thanx kevin,i feel better now,ill try the ac,tomorow,it does seem to do it more when i let off the fuel pedal fast as it goes to idle.i figured it was somthing to do with the biger injectors.against my better judgement i alowed the wife to drive the truck today, {shes kind a leadfoot}she was passing cars on the hiway and putting her foot into it all over town squeeking the tires,so i guess i have her blessing on the mods