DAFF

Have an 1996 L7000 tanker truck which will not pass an E test. Powered by a Cummins 5.9 and a p pump injection system.

Seems the engine keeps increasing its idle point and I have to back down the idle adjustment.(linkage) I was told the truck needed new injectors since one must be lazy. During the test the readings will be good and out of nowhere the truck will puff black smoke. During the puff the HC will go out of the allowable range.

To me the engine runs perfect other than the idle speed creeping up. Is there a possibility that the P pump is not totally in sinc. Not sure where to start ??? I hate throwing parts at a truck for nothing. NTM 4 years ago they turned down the pump to get it to pass.......

infidel

If you're turning the linkage to adjust the idle you probably have things way out of wack.
Adjust the linkage to the measurement below.


Then follow instructions here to adjust the idle http://dodgeram.org/tech/dsl/adjustm...d_Gen-Idle.htm

DAFF

So after I properlly adjust the idle will this help the puff of smoke issue??? I'm thinking there must be more to it??? Have been looking for the how to adjust or turn up the p pump with no sucess!!!

infidel

Turn the idle up a bit higher than recommended for the test.
If it still smokes when you punch it follow starwheel instructions here except turn the top of the wheel away from the engine http://www.cumminsdatabase.com/read.php?id=58

DAFF

Will turn back the star a few clicks and see how it goes. Thanks for all your help!!!! Have a friend with a stock 96, will pull anything but has no get up and go. Will turning the star make much of a difference??

BigErksG2

I would make sure the star wheel is moderately tight to ensure proper function. Tightening it too much will limit top end fueling, too loose and it dumps fuel with no boost (causing black smoke). then move the whole housing toward the cab of the truck about 1/8" at a time until you can mash it without smoke. Once you pass your E test, loosen the star wheel and under that housing is your fuel plate. Slide everything all the way forward and your truck should have a good bit more pep in its step. If you realy wanted to have more power you could grind your fuel plate to a 100 profile.

DAFF

Since the truck had been sitting for a while I decided to put a temp tag on it. Backed off the star wheel and changed air filter and oil. Still a slight puff when you stand on it but not at high revs. before it would puff at WOT. How can you tell if the star has been backed off too far??? Will the engine run funny?? or just lots of smoke??

infidel

It will take forever to accelerate, it's very noticeable.