Timing/advance problem

[steveabn82]

My 86 XJ with 2.8 has interesting problem with the timing. First of all when setting the timing , when I advance past 8 BTDC the engine will slow down and at a point it will stumble. Next when changing my vacuum line on the vacuum advance to a port with constant vacuum the engine will slow down considerable amount.
Ideas ???
;) :)

[Eagle]

What does the factory service manual specify for the timing setting, and how does it say to set it (vacuum connected or disconnected)?

[steveabn82]

The manual says 10btdc and vacuum disconnected. I cannot even get it to 10btdc .

[Eagle]

When you disconnect the vacuum, are you plugging the vacuum line? The engine still needs vacuum to operate, -- they just want you do disable the vacuum advance on the distributor. You can't pull off the hose and leave it open.

[steveabn82]

When the hose is pulled off it is plugged.

[Runnin'OnEmpty]

Steve, no offense, but are you sure you're going in the right direction? When you retard timing, the engine will slow down. Maybe you're retarding it instead of advancing.......?

Sometimes timing marks are hard to decipher. :)

[steveabn82]

No offense taken , It advances for a while then it will retard and slow down.