4.3 Ignition Timing Problems

[slideways72]

GA_googleFillSlot("Forums_ROS_300x250_noad");I recently have completely rebuilt this engine. I am wanting to start it now and there seems to be a problem. I set both marks on the balancer right on spot with #1 at TDC. Put the rotor right on the number 6. I go to start and the motor clacks super loud (almost jamming sound) and wont start. The timing has to be off. I have checked my work over a dozen times. I have moved the rotor one tooth both ways. One way it clacks even louder and the other way it tries to fire every ten to twenty cranks but still bucks the engine. Any advice would be so helpful!!!

The Blazer set for 4 months with no battery if this makes any difference?

[MT-2500]

What year?
Did you get it on TDC compression stroke by holding you finger over plug hole and feeling for compression ?

[slideways72]

It is a 1997...I have done it with my finger and a compression guage.

[slideways72]

More info....Compression test is 155-160 on all cylinders...Pump pressure is good....All plugs are wet when I removed them...Ran OBDII no codes (Engine hasnt ran yet)...Do I need to unplug a wire before setting the timing?

[MT-2500]

The timing is not adjustable.
Are you getting good hot blue spark to all plugs?
Firing order i even on right bank and odd on drivers side withno 1 on front cylinder.
When you said you put the rotor to no 6 is that the 6 on dost housing or cap?

[slideways72]

Spark looks "ok"... I am putting it on the 6 that is molded into the lower section. I have actually broke the starter bendix it is kicking back so hard. Retarding the time helps but it still will not fire... It still bucks a little when it is retarted one tooth but no "piston slap" sound...

[slideways72]

The Blazer came to me with the engine already removed so I was not real sure on the wiring harness and vacum hoses. Maybe a vacum hose in the wrong place or an electrical plug? Would any of that play a role in the timing being so off?

[MT-2500]

Double check you firing order and check cap and rotor for cracks or carbon tracking.
You can not retard or adjust timing on it.
Does it have good hot blue spark to all plugs?

[slideways72]

Spark is good, gap set at about .040....Plugs on right, cap looks good....When I lift the rotor and if i turn it forward one tooth from the molded #6 it does not clack and bang, it still bucks it a little and it will fire every so often but still wont completely light off...Also when I move it one tooth forward it likes to try and fire as i let off the key...

[MT-2500]

What firing order are you using?
Spark to all plugs?
Good compression all cylinders?
Make sure all wires are good.
Try another dist cap and rotor.
Also make sure tdc pointer is right spot.
When no 1 or 4 cylinder valves are rocking one closing and one opening it should be right on tdc.

[slideways72]

New cap and a starter later it fires right up! I took the cap off for about the 10th time and found an extremely small smoke trail....Thanks I appreciate it!!

[MT-2500]

You are welcome and thanks for posting back what you found.
Them flat top caps are bad about that.
Glad you got it fixed.
The timing is not adjustable but you need to get it on a engine capable scanner and set the camshaft retard as close to 0 degrees - or + as you can get it.
If not set good it may missfire and burn up cap and rotor.
Good luck.
MT