Distributor/Timing Problem

[dkennedy]

I'm in the process of removing the wires and components from the top of my motor in order to remove the upper intake and while pulling plug wires from the distributor cap so I could get at the fuel lines the distributor rotated... for whatever reason it was a little loose. Since these Vortec engines are timed by sensors, how in the heck do I get the distributor back to it's correct position?

It's a 1998, 5.7 LTR

 

[skylark]

It has to be set with a scan tool to be proper. IIRC it can be +or- 4 before it will throw the light.

 

[outalne94z71]

in this case most likely will need a scanner, i did intake gaskets before without using a scanner, just had to mark exactly where the rotor was pointing and exactly where the distributor sat

 

[SubLo]

The reading is + or - 2 degrees.You need a scantool that can read CMP (Cam Retard). Those are few and far between on the consumer side. Mechanics and dealers have them mostly. The distributors in our trucks, unlike other small blocks, cannot be adjusted timing-wise by rotating the housing. That adjusts the CMP not timing advance. Timing Advance is computer controlled only in our Vortecs. Your best bet: mark it and return it to position as closely as possible. You may get really lucky and hit it head on. But most people aren't so fortunate and you'll wind up with a CEL/DTC, P1345 until you adjust it again.

 

[SubLo]

I fixed this myself btw, without paying a dime for a mechanic's scantool. My "Torque" app on Android reads CMP but doesn't have the functionality out of the box. I figured I'd try my hand at some minor adjustments just by "eyeballing" it. So, I loosed the distributor, and turned it 2 or 3 degrees, revved, waited and watched for the C.E.L. After 3 or 4 attempts, success! It's been trouble-free and C.E.L./D.T.C. free for several days now. I tried it because I guessed it couldn't possibly be off some crazy number like 45 degrees. It must have been somewhere near the ballpark as the truck ran fine.

 

[dkennedy]

I also was able to fix this myself... there was a place that had an unusual amount of dirt buildup on the distributor that stood out enough that I was able to match it to the buildup on the intake and everything was A-OK.