help plz with 97 tahoe distributer

[tplow10]

recently replaced head gasket on 97 tahoe 5.7 vortex...upon compleation engine started ran very rough.. upon checking multiple things found that distributor had small crack in it...purchased new dist. installed to what i think was correct position(how do i check) now engine will not start at all. so i guess i need help with distributer install or correct positon.

Please help any ideas will be greatly app.

Tplow10

[16th hippy]

ok, either you didn't hook up some electrical stuffs, or dist is off time. do you hear ANY signs of starting, hiccups, chugs, or anything? since it ran before, gonna assume the dist is heart of problem. if you replaced anything with cam or timing chain while working on heads, then this could be suspect too.

to check is dist is timed correctly.
first, disable fuel and ignition systems
remove #1 spark plug. get engine to TDC COMPRESSION on #1. making sure it is on compression stroke is VITAL. remove dist cap, rotor shuold be pointed at #1 cylinder, if not, remove dist and re-install it so it is pointing at #1. reinstall all removed parts, making sure all electrical stuff is connected, and try to get dist set as close to ZERO deg as possible. try to start. if starts and runs, then set timing to spec on fan shroud, should be ZERO deg. follow instructions for setting timing on decal. hope this helps, please post back results.

[wafrederick]

You cannot do it with a timing light and the timing is not adjustable.You set the distribitor with a scan tool and the spec is 0 degrees.Look for Cam sensor retard in the data stream.It says on the sticker timing not adjustable and consult service manual.

[16th hippy]

timing is not adjustable as a spec. when replacing a distributor, it needs to be set to zero deg. the computer does the rest. a timing light CAN be used to set it to zero.

[jonnik]

16th hippy, what is the procedure for using a timing light to set the cam-crank offset? I had to replace my distributor and I'm getting the fault codes.

[16th hippy]

don't know, never had to set that, but wouldn't that be done mechanically with the timing chain? unless there is something major i don't know about setting timing(and ther could be), i have only ever used a light to set timing with a distributor. and the last 5 distributors i have replaced, i marked everything and used alot of visual cues and never had a problem.

now, you are getting fault codes, what are they? assuming this is also still a 5.7L in a tahoe.

[777stickman]

16th hippy. I think you're putting out some wrong advice for the '96 and newer OBD2 systems. Read the post by "wafrederick". What he says is absolutely correct.

The "cam offset or cam retard" mode can only be accessed by a high end scan tool. When this mode is selected it puts the VCM into a "base" timing mode. That is when the timing can be set to 0 degs as read from the scan tool, not a timing light.

As far as dist installation on these OBD2 motors, the rotor needs to be pointing at a small #8 cast in the dist ( for V-8's) when the dist is fully seated and the flat part of the dist is facing forward. This needs to happen with the #1 cyl at TDC on the compression stroke. There is a mark on the dampener and a tab on the timing chain cover to show TDC.

Hope this clears some things up.

[16th hippy]

Originally Posted by 777stickman

16th hippy. I think you're putting out some wrong advice for the '96 and newer OBD2 systems. Read the post by "wafrederick". What he says is absolutely correct.

The "cam offset or cam retard" mode can only be accessed by a high end scan tool. When this mode is selected it puts the VCM into a "base" timing mode. That is when the timing can be set to 0 degs as read from the scan tool, not a timing light.

As far as dist installation on these OBD2 motors, the rotor needs to be pointing at a small #8 cast in the dist ( for V-8's) when the dist is fully seated and the flat part of the dist is facing forward. This needs to happen with the #1 cyl at TDC on the compression stroke. There is a mark on the dampener and a tab on the timing chain cover to show TDC.

Hope this clears some things up.

actually it does. as i said, never had to "adjust" timing on any i have done due to marking the dist and so on. as for lining up the rotor with that #8 on there, makes sense as when dist gear meshes up with cam gear, the rotor will then be pointed at #1...or it should anyway. i have on the other hand had to do the entire process on older motors, and using the scan tool on a newer one seems to be the same as unplugging the "timing connector" on the older ones. in any case, i do appreciate the info and will have to remember that if i ever have to re-build one of the newer ones.