I let a shop do my fuel injectors a few months back and I saw on the paper they charged for a cap and rotor too. Ever since, every once in a while the blazer will have a hard/rough start. I did research, saw that AC delco parts should be the only cap and rotor used. They put in master pro or something like that. Bought ac delco parts and put them in. But I've looked at some pics on the internet and does this look like it's in the right position? Thanks.

 

The rotor will only mount in one position. There are two locator pins on the under side of the rotor, and they must align with the holes in the top of the distributor. The rotor must fit flush against the distributor with no wobbling, before you tighten the screws. If the engine starts and runs with no check engine light, and no P1345 in memory, the distributor is timed correctly with the camshaft.


As for the direction of the rotor segment: The timing marks on the dampener must be aligned like this:





AND the rotor must be pointing at the "6" on the distributor housing, like this when #1 piston is at TDC of the compression stroke:

 

Ok, thanks! Well there has not been any check engine light on or anything. I'm hoping putting ac delco parts in will help. I'll report back.

 

Cap'n...isn't there the re learn thing to be done also or am I thinking about something else?

 

Good point! No relearn, but camshaft retard should be checked, & adjusted if necessary, when the distributor is removed. If it's out of spec, it can definitely cause a misfire without a check engine light.

 

Without a check engine light, the distributor is timed correctly, so replacing cap & rotor can't hurt, it can only help. Might want to check camshaft retard though, it can be out of spec up to ~25 degrees, (which is serious) before the check engine light will come on. It requires a scanner capable of accessing the data stream. You can hire it done for about an hour labor charge. Make sure the tech is aware of the adjustment, and how to do it.

 

I put in the ac delco parts. It started with no CEL. Of course it was starting before but after driving it to places, it had a rough start, have not driven it anywhere yet. I really want to do everything myself on the blazer if I can. I have been looking at the GM Tech scanner 2 to buy. I have to eventually replace the timing cover (oil leak) and I'm pretty sure it can do both (relearn for timing cover and scan camshaft) after googling and searching.