Injector pump timing

[Gus97]

New long block installed, tach, cruise control and exhaust brake now not working. Could go up I 80 to Donner Pass at 62 mph @ 2,000 rpm in 5th gear now cannot go up an ant hill without shifting down to 4th. The shop is having a hard time timing the pump, any help will be welcomed.
Thank you,
Walt

 

[BigPapa]

There are several different methods to set the timing on a 12-valve. This is the simplest way I know to set your timing without any special tools.

Pin the pump, knock the pump gear loose, TDC the engine, then make a mark on the balancer for TDC where you have a reference or a pointer of some kind.

Stock timing is listed on the Data Plate on the Driver Side of the Front Gear Case. My ’95 auto is factory timed at 12.5.

Measure the diameter of your damper. I’m running a 2nd Gen 24-valve damper and it is 9.25” diameter (I don’t have a 12-valve damper to measure). Multiply the diameter (9.25” for me) times 3.14 (Pi) to get the circumference (29.045” for me), then divide the circumference by 360. On my 24-valve damper, that means .080” is one degree.

Looking at the front of your engine, the crank turns clockwise when running. If you’re looking at the top of the damper and your pump is timed at 12.5 and you want 17.5, you would make a mark .4” to the Driver Side of your TDC mark. If you made your TDC mark from below it would be the opposite, .4” to the Passenger side.

Now, rotate the engine backwards until your new mark is at your reference or pointer (I use the alternator pulley nut). Make sure to disengage the Pump Timing Pin and the TDC Timing Pin, then use a barring tool or some other method to keep the engine from turning and tighten the pump gear back down (after making sure the hole in the gear and the pump shaft are clean and dry) to 144 ft/lb.