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99 yukon 5.7l cam retard adjusting

Matthew Andrews

By Matthew Andrews
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Matthew Andrews New Member

Matthew Andrews

Posted
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Hey, so I recently changed the distributor in my 99 yukon 5.7l, and I am having a super hard time getting the cam retard back to zero. It is currently off by 30°. I have tried moving it a tooth forward and a tooth backwards and both situations result in a no-start, although at 30° it starts and runs daily but I'm pretty sure my mpg has tanked. I have reinstalled this thing like 4 times now trying to see if I can get any closer and its just not happening and I'm getting pretty frustrated. 

 

Is there something I'm missing or forgetting? Could it be two or 3 teeth I need to skip? I tried googling but couldn't find the number of degrees each tooth consists of. Also I'm definitely reading the cam retard at above 1k rpm, and I've tried just spinning the distributor clockwise but it cant go any further without hitting the plenum. 

 

Everything I read says this is so easy as long as you have a scanner, but theres something I'm not doing right lol. Also is there any way to try out different teeth without having to reset tdc to get it back? 

 

Thank you for your time! Sorry if I rambled! 

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

If I remember right, there was a trick to getting it set right by grinding the hold down stop, or part of the distributor housing to allow the distributor to rotate whichever direction it needs to move in. Been a long time since I've dealt with that, so I've forgotten exactly how it's done. I'm sure someone has a YouTube vid on that, or a Google search will turn up something. It was a common thing 10+ years ago.

 

Things were much simpler in the old days before all this computer controlled crap took over.

Matthew Andrews New Member

Matthew Andrews

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Posted
10 minutes ago, Jsdirt said:

If I remember right, there was a trick to getting it set right by grinding the hold down stop, or part of the distributor housing to allow the distributor to rotate whichever direction it needs to move in. Been a long time since I've dealt with that, so I've forgotten exactly how it's done. I'm sure someone has a YouTube vid on that, or a Google search will turn up something. It was a common thing 10+ years ago.

 

Things were much simpler in the old days before all this computer controlled crap took over.

If you're talking about the part that mounts the distributor, I am using one that allows the distributor to freely spin when loose, but the distibutor will only turn so far before the cap butts up against the plenum. This is why I've come to the conclusion that its slotted in the wrong tooth, but I don't know enough to get any further than that lol. 

 

Thank you for your response! 

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted (edited)

If it's hitting, you'll need to reclock it - in other words, go forward or backward 1 tooth (whichever direction gains the necessary clearance).

 

On the old school 350 before this computer crap, you could run the distributor base in any position you wanted 360° around, so long as #1 was timed correctly - you could swap wires around in the correct firing order to achieve this. If I'm remembering right, there was something on these newer distributors that prevented that. Probably the primary or secondary wires, but I vaguely recall something on the distributor shaft that prevented that as well. Going off my vague memory, if you hit the correct tooth, you had some wiggle room to get it +/- 2°.

 

Definitely need a good scan tool, though. Not only to dial in the retard correctly, but you'll have to do a crank relearn afterwards as well.

Edited by Jsdirt
Matthew Andrews New Member

Matthew Andrews

Posted
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31 minutes ago, Jsdirt said:

If it's hitting, you'll need to reclock it - in other words, go forward or backward 1 tooth (whichever direction gains the necessary clearance).

 

On the old school 350 before this computer crap, you could run the distributor base in any position you wanted 360° around, so long as #1 was timed correctly - you could swap wires around in the correct firing order to achieve this. If I'm remembering right, there was something on these newer distributors that prevented that. Probably the primary or secondary wires, but I vaguely recall something on the distributor shaft that prevented that as well. Going off my vague memory, if you hit the correct tooth, you had some wiggle room to get it +/- 2°.

 

Definitely need a good scan tool, though. Not only to dial in the retard correctly, but you'll have to do a crank relearn afterwards as well.

Ok I'll try again tomorrow, just one more question. If the cam retard is reading 30° (positive) then I need to rotate forward(clockwise) correct? 

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

It's been too long - I couldn't tell you for sure with any degree of accuracy ...

 

I'd just watch the scan tool as you turn it - that will tell you which way you need to go.

  • 3 years later...

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