1998 yukon Mystery p0300 and rough idle still

[OilBurner2003]

Yep, but a quick check is to see if the dimple (below the pin) in the gear lines up with the paint mark and shows the rotor pointing to the “starting” spot before it drops in.

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Roger, I’ll look at that too.

 

[exp500]

If you want a self taught camshaft math lesson, remember you are starting with 720 degrees divided by #of teeth on dist gear. So Yeah pay attention to the engage gear, oil pump and seated dist rotor positions so any change necessary you know where to move pump and rotor. OR you can feel for them but that takes days.

 

[OilBurner2003]

If you want a self taught camshaft math lesson, remember you are starting with 720 degrees divided by #of teeth on dist gear. So Yeah pay attention to the engage gear, oil pump and seated dist rotor positions so any change necessary you know where to move pump and rotor. OR you can feel for them but that takes days.

It’s certainly a hassle. I will keep this in mind, thank you!

 

[OilBurner2003]

Yep (assuming you haven’t been off a tooth) but a quick check to see if your distributor was assembled wrong is to see if the dimple (below the pin in the gear) lines up with the paint mark and shows the rotor pointing to the “starting” spot before it drops in.

View attachment 386319
View attachment 386320

morning sir, this is the offset with the old distributor. not there and still hitting the intake, but its way closer. only 6 degrees out of spec instead of 19. Got it started first time!

 

[east302]

Hmm, interesting.

I’d check the dimple orientation on the new one when the rotor is at its “first” position before it turns when seated. Maybe the distributor folks messed up at the factory. Otherwise I’d swear you were off a tooth but you’ve probably stabbed this thing in a hundred times by now, lol.

Can you grab pictures of the new vs old ones installed showing rotor orientation and also one of the corresponding balancer/timing cover marks? Just making sure - you have the balancer line lined up with the center notch on the timing cover tab right?

 

[OilBurner2003]

Hmm, interesting.

I’d check the dimple orientation on the new one when the rotor is at its “first” position before it turns when seated. Maybe the distributor folks messed up at the factory. Otherwise I’d swear you were off a tooth but you’ve probably stabbed this thing in a hundred times by now, lol.

Can you grab pictures of the new vs old ones installed showing rotor orientation and also one of the corresponding balancer/timing cover marks? Just making sure - you have the balancer line lined up with the center notch on the timing cover tab right?

When I slide the distributor in, I have the balancer marked up with the timing notch. Then I wiggle the distributor onto the oil pump shaft, if it doesn't slide in I rotate the crank slightly until it falls in place. I will take pictures when I can! Gonna take a break and then go do that.

 

[east302]

Sounds like that’d be the same as bumping the starter and a lot of people do it that way. Don’t know for sure. Maybe something’s happening in the process.

Try leaving it at TDC and not bumping the crank at all. Rotate the oil pump shaft with a long screwdriver to align with the distributor tang and then drop it down.

I’ve always stabbed it with the rotor at the starting point (4 o’clock ish where the dimple and mark on the shaft align) and flat part parallel to the intake (cap wires thus perpendicular to the engine centerline) to make sure that I’m in the right spot. Eyeball and get the pump shaft into the right orientation.

This one time (at band camp) it actually fell into place the first try. Usually takes me two or three or fifteen tries depending on my mood.

It sort of helps to draw a sharpie line on top of the screwdriver in the same orientation as the bit. Easy to lose track of where you’re turning, otherwise.

But yeah, compare those two distributors side by side and see where the rotors are with the dimples in the same spots.

 

[OilBurner2003]

Sounds like that’d be the same as bumping the starter and a lot of people do it that way. Don’t know for sure. Maybe something’s happening in the process.

Try leaving it at TDC and not bumping the crank at all. Rotate the oil pump shaft with a long screwdriver to align with the distributor tang and then drop it down.

I’ve always stabbed it with the rotor at the starting point (4 o’clock ish) and flat part parallel to the intake (cap wires thus perpendicular to the engine centerline) to make sure that I’m in the right spot. Then eyeball and get the pump shaft into the right orientation.

This one time (at band camp) it actually fell into place the first try. Usually takes me two or three or fifteen tries depending on my mood.

It sort of helps to draw a sharpie line on top of the screwdriver in the same orientation as the bit. Easy to lose track of where you’re turning, otherwise.

But yeah, compare those two distributors side by side and see where the rotors are with the dimples in the same spots.

What you just suggested was making me wonder the same thing, I was actually about to mention it. All my tools and I can't find a long screwdriver that will fit down there, Someone made a point that you can bump the starter because the distributor is already meshed with the cam gear therefore technically, "In time." But I'm starting to wonder if that's 100% true or not...I'll have to either find a screwdriver or something long that can fit in that slot. Maybe I should try installing the new distributor with that method and see what happens?

 

[east302]

Compare them and make sure that dimple orientation on the gear matches your old one but, yeah, I’d try this way.

 

[OilBurner2003]

Compare them and make sure that dimple orientation on the gear matches your old one but, yeah, I’d try this way.

Roger, got some work to do!