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1999 GMC Suburban 5.7 Timing Issue
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faust4456
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Feb 18, 2013, 12:32 AM
Post #1 of 15
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1999 GMC Suburban 5.7 Timing Issue
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OK. I've got a '99 GMC Suburban with a 5.7 Vortec with 156k. The issue I'm having is somehow the timing goes 180 out. I pull the #1 spark plug. I turn the crank shaft till I feel the air on my finger and make sure it's TDC, line up the dots on the timing gears and make sure the rotor is pointing to number one plug or the little 8 pressed on the dizzy. From what I understand that's the correct way to time it. I put the plug and wire back on and screw down the cap. After I do all that and try to start it, it cranks but won't start. I go back and pull the number one plug and feel the air once again. But, here's the weird thing. When I look at the dots on the timing gears the crank is at 12 o'clock like it's suppose to be but the cam gear is at 12 o'clock also instead of 6 where I set it and the rotor is pointed to the number 8 plug. How is that even possible?
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Discretesignals
Ultimate Carjunky
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Feb 18, 2013, 6:04 AM
Post #3 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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Takes two rotations of the crank to rotate the cam one time. If you have the dots together when you put the distributor in with it lined up to #1, the distributor will be 180 degrees out. You need to put the distributor lined up on # 1 with the crank dot at 12 and cam dot at 12.
Another words line the dots up and then turn the crank one revolution. Then install your distributor on #1.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Feb 18, 2013, 6:10 AM)
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Hammer Time
Ultimate Carjunky
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Feb 18, 2013, 2:20 PM
Post #5 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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Here is what the service manual says.............
It takes 2 revolutions to come back to that point.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Feb 18, 2013, 2:21 PM)
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Discretesignals
Ultimate Carjunky
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Feb 18, 2013, 6:06 PM
Post #6 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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If you put the dots together, #6 will be TDC. If you install the distributor pointing to #1, it will be 180 degrees off.
If you put both dots up, then install the distributor pointing at #1, it will run.
The only time you need to be concerned with the dots is when you put the chain on. The chain has to be installed dot to dot.
Note: #1 in the distributor cap doesn't point directly at the #1 terminal where the plug wire connects, it actually points to the opposite side of the terminal due to the cap's design.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Feb 18, 2013, 6:06 PM)
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faust4456
Novice
Feb 20, 2013, 12:43 PM
Post #7 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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Thank you guys so much. It turned out that with your help I was able to set it up right. The trouble was since I am not a mechanic I was told by a mechanic that I could start it up and run it for a couple seconds without putting it all back together. What I didn't know is that there is a sensor that goes into the timing chain cover that needs to be positioned in an exact spot to tell the computer that it's ok to fire. So, of course it wouldn't start. But, that's how we DIY's learn. So, now it's running better. But, still a little ruff. I've been told that I need to take it to a shop to get it fine tuned. I will if I have to. But, is that true?
(This post was edited by faust4456 on Feb 20, 2013, 12:48 PM)
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Tom Greenleaf
Ultimate Carjunky
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Feb 20, 2013, 2:28 PM
Post #8 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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I believe this engine does require special equipment to get timing perfect.
Long retired now so not sure for each but think this is one of them you can't just set exactly like much older ones,
T
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Discretesignals
Ultimate Carjunky
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Feb 20, 2013, 5:49 PM
Post #9 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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You'll need to have two things done. One is cam sensor angle offset and crank angle relearn. They both require a high engine scan tool to perform the procedures.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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Hammer Time
Ultimate Carjunky
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Feb 20, 2013, 7:18 PM
Post #10 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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I think this one is a one position lock down and not adjustable anyway.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Hammer Time
Ultimate Carjunky
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Feb 21, 2013, 8:14 PM
Post #13 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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The timing is not adjustable at all. If the distributor does turn, it changes the cam sensor synch and the synchronization of the primary ignition to the secondary. It's adjusted using a scan tool.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
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Feb 22, 2013, 5:52 AM
Post #15 of 15
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Re: 1999 GMC Suburban 5.7 Timing Issue
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Long retired now "faust" and own two of these engines. Never touched - yet (super low miles) I still have now old friends with shops with the stuff and would let that part go to them. Other things fine but not reasonable to own the equipment for something so primal now for a one or two time deal.
I support DIY and if you think about it we regulars in the trade all started somewhere not just born with the tools and skills. It's a talent to know when something is not worth DIY for cost of equipment or learning how to use it especially if just once.
DIY is both a chance at saving a buck and the satisfaction but has it's downfalls. I seriously doubt you can rent anything to finish this off.
Know that it costs a fortune for those in biz. That nasty bill isn't all profit by any means - not even close. I'm trying to think of a trade that requires such an up front investment like this and really can't think of one. Let the pros finish your perfect work. I say perfect because it's a ton harder to deal with something that was messed up!
T
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