I am trying to diagnose a problem on my 2000 3/4 ton 4wd turbodiesel. It had the superchips 40hp chip when I bought it and run good. I thought adding 100HP J3 injectors would be the way to go. It now bucks at about any engine speed in third through fifth gear. If I put it to the wood it straightens out and takes off like a shot. I have replaced the clutch thinking that was it but it wasn't. Gearbox, transfer case and differential oils all came out clean. Any ideas would be greatly appreciated, Cyclops.

 

Mine does this with 155+ injectors and an EZ. It wont do it at all with my PM3 which is only a fueling box. I therefore concluded the additional timing that is inherently created from larger injectors plus the additional timing of the EZ is what causes mine to do this. IS your superhcips a timing device??? I bet it is... Take it off and I bet it will be as smooth as can be. Same thing on mine too, if you floorboard it its smooth and FAST !! Mid throttle is where the problem is.... Got to be timing.....



Kevin

 

You have added enough power to make the rear springs wind up. Mine has done this since the injectors were put in on the original engine. With a full load it will buck up a hill at full throttle also. It is because there are five inch riser blocks adding to the leverage of the spring wrap. Lower power will not do it. You probably also get a chug when starting off with a heavy load in first gear. There is no cure for it unless you add traction bars. It will not hurt anything left as is. It just shows that you have exceeded the design of the rear spring setup. Mine has chugged like that for most of its life of 326k.

 

Did you replace the tips on your stockers with the jammers yourself? And did you have them pop tested? Do what kevin recommended and pull the superchips off and see what happens. Sounds a little bit like fuel delivery. Do you have gauges?