1994 trucks and Suburbans had a 1 year only DS4 injection pump with the model number "5068"

This pump is NOT interchangeable with the other styles of DS4 pump due to the tune/programming being specific for it.

The 5068 pump used the following GM broadcast codes on the Prom chips:

BXRF

BPBN

BMSD

BPBM

BLRL

BJAX

BKWJ

We've also seen BNTH, BNTF, and BNMN

Have us match your tune to either the 5068 or 5521 pump accordingly! We can fit either style pump to any model year 6.5. Both OBDI and OBDII trucks.

Email us these 2 data points and we'll verify a mismatch

• Model number of injection pump you have installed

• Broadcast/ID codes off you factory prom chip

• Desired Timing Measurements

  • 5521 tunes typically don't idle below 9* Desired Timing Advance

    • If you see 4-5* desired, then you know the tune is for a 5068 pump

    • You can apply this same logic in reverse for a 5068 pump on a 5521 tune

• Fuel Rate

  • This chart can help advanced users view the idle fuel rate with a scan tool. Both ways of mismatch are shown to help diagnose if the issue is present

Light Duty, EGR equipped trucks didn't get the 5068 pump. So, this issue isn't typically seen on 1500 or LD (6 lug wheel) 2500 vehicles