How to check Timing on '89??

[Redbob45]

Please help.
CHecking the timing on my '89 L98, I read something like 25 degrees BTDC at idle. A friend says there's a wire I'm supposed to disconnect before checking, but my shop manual doesn't mention this - in fact, it doesn't even say what the timing is supposed to be at idle.
Is it 6 degrees? What wire do I disconnect? Help!

Thanks,
R

(PS: I'm also registered from my work address as "Redbob", but I forget my password - I'm not really such a newbie as you might think - judging by the dumb question...)

 

[Redbob]

It's me! And I still could use some help!
Thanks in advance, y'all.
- R

 

[mike 1985]

my 85 has a wire just to the inside of the brake booster that you have to disconnect to check and set base timing. Your base timing should be set with the car warmed up and off high idle, then unplug the (est) connector and check timing. You should have a GM sticker either on your fan shroud or on the under side of the hood that tells you what to set base at. Mine suggest 6 deg.

Make sure to re plug in the EST or you'll get a SES code and the car will backfire when trying to accelerate.

Hope this helps

 

[Redbob]

Thanks, but I was hoping for a little insight as to WHICH wire that is!
I see lots of them in that vicinity.

 

[Eagle85C4]

Should be a tan and black stripped wire with a connector just down below the booster near the rear of the head...

 

[CKA_Racing]

two wires, one tan or brown looking wire and one black.

 

[Redbob]

Gentlemen:
Thank you both!
I've found it now, and the timing is "spot-on" as we used to say when I drove Brit sportscars, before I saw the light!
(Sometimes the light at the end of the tunnel is just the headlight of an oncoming train!)

Regards,
- R