As part of the rewire project, the truck got a new EFI controller MS3 which can do sequential injection and ignition while still being able to run additional injectors for other purposes e.g. staged injection or dual fuel (e85/methanol).

So over the Canada Day weekend I re-installed the stock exhaust sprocket/VVT/cam wheel (its all one piece), which will allow full sequential operation.

Another 4200 is already running full sequential on MS3 - just with a different set of crank & cam wheels. The boys report that the throttle response without any injector timing tweaking is outstanding. Wiggle the throttle and the engine just zings.

So this week its my turn to finally test the native GM 7X and 4200 cam wheel s/w.

I have one more work item to complete, that is to install 6 EGT's into the runners. This way I can monitor each hole and if any are lean (or rich) I can individually adjust the AFR on a per cylinder basis once running full sequential.

Later I'll try the VVT code once I have some other items working like closed loop boost control....

The feature list on the MS3 is quite rich and growing. Latest addition is knock sensing windowing. This allow false knock signals to be ignored until x deg before the ignition event and after y degrees after the ignition event.

Once the VVT and sequential code is fully tested we now have a fully tunable EFI solution for the 4200 (less the drive by wire). One of the aftermarket companies offers a stand alone DBW box. Guess they have the $$$ for a big insurance policy.

More to follow


Last edited by efi-diy; 07/05/11 02:02 AM.
51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them