Need help with DS4 injection pump

[Bruce Ostien]

I have removed the intake manifold in order to remove the PMD so that I have a spare. I ordered a new driver which also came with a new short harness. While installing the new harness, I broke off one of the studs that stick out of the back of the injection pump. A red and black wire connect to these studs. The two connections are then covered by a boot.

I assume that will need to remove and replace the part that the studs protrude from. This component is held in by two T10 torx screws. I have removed these. There are two holes that look like they accept a special tool to unscrew the part. Am I on track so far?

Thank God for you veterans to keep us rookies out of hot water.

It's a 99' Suburban

[gmctd]

That is the Fuel Solenoid - it's precise position is calibrated on a Bacharach or equiv inj pump flow bench to meet Stanadyne specs for Inj Pulse Width and Closure Time.

At only 0.005" travel, adj is impossible on vehicle.

Try removing the final nut from the broken stud, filing it thin to get some clearance.
Will require some artful work with a small file on the stud threads to allow removal, but can be accomplished.

[Bruce Ostien]

The studs themselves are turning. Is there another wire soldered to them on the inside that will break off with too much turning?

Thanks for the help GMCTD.

[Phil Holmen]

Try to solder a wire directly onto the stud, then glue it to be sure it will not come lose.. just a suggestion...

[gmctd]

Could be, but also could be ring lug terminals.

Real answer - unknown.

Got a DS-4 I've been intending to dissect for some show and tell - reckon I'll go pull the FS off to check that out.

I'll get back with you on that.....

[gmctd]

Ok - those are actually 0.125"dia shoulder studs, screwed down into the coil, also used as structural fastening\locating elements.

On this '97 5288, they both unscrew, at about 1" length, making contact internally.

I would say you could back them out enough to get a split ring terminal between the hex head and the white insulating shoulder washer, and re-tighten.

Or, just remove and replace - possible GM has them, or the local Stanadyne service shop.

[Bruce Ostien]

Thank you so much for that bit of investigative work. Unscrewed just as you said. I'll see if I can get one from a local injection pump service shop.