OK. I've got a '99 GMC Suburban with a 5.7 Vortec. The issue I'm having is somehow the timing goes 180 out. I turn the crank shaft till I feel the air on my finger, line up the dots on the timing gears and make sure the rotor is pointing to number one plug. From what I understand that's the correct way to time it. After I do all that and try to start it and 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 it that even possible?Update:The dizzy is already installed. It's not a problem with that. If I have it TDC and all the marks where they should be and the rotor is on the #1 plug. How could it possibly end up 180 degrees off is what I'm basically asking. I'm sure it's something simple. But, I'm not a mechanic. From everything I've seen on line I'm setting it the right way.. Created by stephen f. cars-transportation-en - car-makes-en - gmc-en

1999 5.7 vortec timing?

May 2021 6 138 Report

1999 5.7 vortec timing?

OK. I've got a '99 GMC Suburban with a 5.7 Vortec. The issue I'm having is somehow the timing goes 180 out. I turn the crank shaft till I feel the air on my finger, line up the dots on the timing gears and make sure the rotor is pointing to number one plug. From what I understand that's the correct way to time it. After I do all that and try to start it and 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 it that even possible?

Update:

The dizzy is already installed. It's not a problem with that. If I have it TDC and all the marks where they should be and the rotor is on the #1 plug. How could it possibly end up 180 degrees off is what I'm basically asking. I'm sure it's something simple. But, I'm not a mechanic. From everything I've seen on line I'm setting it the right way.

Cars & Transportation / Car Makes / GMC

Verified answer

OMG, he hasn't a clue. Dude, forget Yahoo answers. You are only going to confuse yourself more. Go to your favorite auto parts store and invest in a Haynes or Edmunds manual for your vehicle. It will be cheaper than all the money you are going to spend on aspirin.

doornobk

Don't worry about where its physically pointed. Also note with that stupid flat crab like cap where the wire connects may not be the closest terminal, you have to follow the bump in the cap to see which terminal they go to. With the cam sprocket at 6 rotor should be pointing at the #6 terminal. With cam sprocket at 12 rotor should be pointing at the #1 terminal. It seems dumb but that is just the way its always been. It would make more sense if they just put the dot at 6 for #1 but whatever.

Air pushing out the spark plug hole is a valid method. When that happens with the timing mark at 0 the rotor should then be pointing at the #1 terminal (assuming that your finger was on the #1 hole). You can use this method for #6 also because the timing mark lines up for both 1 and 6.

Your problem may be the 'indexing' of the distributor. Since the timing is computer controlled based on the crank position sensor all the distributor has to do is get the terminals lined up. The sensor in the distributor is the cam sensor but all that does tells the computer which half of the cycle the cam is on to allow for sequential fuel injection. Typical distributors used to have the pickup to trigger the spark internally so this was not an issue. It was only the 96-2000 trucks that had this system.

There is an official method and tools to index the distributor but the DIY way requires an extra distributor cap, timing light, and some general purpose implements of destruction. What you do is take an old cap, pick a terminal that does not have a internal line crossing over it and hack the plastic out on both sides of the terminal. You then install this cap and connect the timing light to this terminals wire. Start or try and start the engine. The timing light should flash when it gets to this terminal and based on the flash you can rotate the distributor slightly in either direction to get the rotor fairly well centered on the terminal. You then lock down the distributor and install a good cap. After you get some miles on it (next oil change?) you can look at where the crud is starting to build up inside the cap. If its not centered real well you can make a slight adjustment just by eye to get it centered better.

Shaun H-A

Cam turns half the speed of the crank. If you put the dot on crank gear at 12 and the dot on the cam gear at 6, that is only for lining it up to install timing chain, NOT for lining things up so you can put the dizzy in.

Once the engine is running, you have to also set the "cam retard offset".

Turning the crank until you feel air pressure on #1 is only a sign then that you are on the compression stroke for #1. At this point, turn the crank by hand and line up the harmonic balancer's timing mark with the pointer. That will get you into the ball park so then you can install the dizzy.

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Im with PATRICK on this one!!!!!!!!!!!!!!!

Somethings, certain people need to just leave it alone even if you do have the service manuals for it!!

Why are you putting finger & feeling air??? That means crap in this field!!!!!! A good technician would have marked the distributor & rotor position prior to ripping all that crap apart so we dont have to waste time with alignment. We also would have put it at #1 TDC as well.

First off, why did you rip into the timing???? How do you know the timing isnt correct & you have a different issue as to why it wont start???? Do you even own a timing light??? Have you even checked to see if your getting spark at the wires??? Fuel pressure??