Vortec oil pump on a gmc jimmy

If the Pontiac engine is similar to the small block Chevy, you have, I believe, a hexagonal shaft that runs from the end of the distributor shaft down to the oil pump. This is turned when the distributor shaft is turned by the meshing gears on the camshaft and distributor shaft. I would say that you are probably going to have to re-time the engine. Find TDC, then replace the distributor. It won't matter a whit to the oil pump if the gears are one or two teeth off, but it will matter a great deal if you distributor is not installed so it can be adjusted a few degrees when you get to "fine timing" the engine.

You should be able to download information on how to time the engine (finding TDC, etc.). Failing that, a trip to the library may be in order.

you are out of timing or you put your distributor 180 off or you may have hooked the plug wires up wrong you may have 2 in the wrong place

the oil pump is in the Oil Pan.

it being plastic it might float and block an oil line id drop the oil pan and get it out its a pain staking process

HAVE ECM "CODE" READ......IT SHOULD LEAD YOU TO A FAULTY COMPONENT EGR, MAP SENSOR, ETC....

IS THEIR WATER IN THE OIL? CHECK THE PLUGS TO SEE IF THEIR WET.YOU MIGHT PUT SOME PLUGS IN IT IF WET TO SEE IF IT WILL RUN.THEN PUT SOME HEADGASKETS ON IT.BUT IN REALITY NEW MOTOR WOULD BE BEST.

The problem is either your fuel pump relay is overheating our your fuel pump is over heating. They also have the problem with the wire connector on top of the fuel pump melts. This is a known problem with them, when you but a new fuel pump they give you a new connector and a service bullentin regarding this problem.

back down to the drivers side of the distributor. just to the right of the base of the distributor you will find it. right, as in facing the distributor from the front of the blazer. you can find a picture of it in the how to vortec intake section on helpwrench.com

just to the right of the base of the distributor. right being facing the engine.

The "spider" injector is the problem. You're right that one of the injectors is stuck open, unfortunately it has to be replaced as an assembly. This a common problem on the Vortec V-6's. When you were checking the fuel pressure, the fuel was passing through the open injector, giving you a low reading. After replacing the injector assembly, be sure to change your oil before you start the engine. I'd be willing to be you have a pint or two of gasoline that has gotten into the crankcase. That injector unit will cost you around $350. It's not too hard to put in, just be careful.