Brown/black advance wire - unplugged - idles better and runs about same.

[Jwernatl]

Hey All, a few weeks back I set my fully warmed 350 timing to 1-2degrees - to do so, you know we have to unplug the advanced brown/black wire- I did

Once I got done - I plugged line back together, idle jumped from 600rpm to about 1100rpm, and the truck runs 'rich' to much fuel - or not burning it -

I'm wondering if my ECM is reading my temperature correctly. - or distributor out of wack? or how about vacuum line? Is there a vacuum line going to distributor?

reason...

Just fyi too - the next day I double checked my the timing - unplugged the brown/black wire - checked timing - it was perfect. I shut the hood, not putting the line back together.

And for a week, I've noticed the truck idling perfect. And, there was no 'rich - too much fuel smell' -

A few days ago- it hit me I didn't plug the advance wire back together.

I immediately checked, sure enough, it wasn't plugged together. I plugged it together - the idle jumped from about 650rpm to 1000 - and that smell is back.

I put a 195 thermostat in a few weeks ago - seems to be perfect.

Also - the idle being up like that - it makes my tranny and driveline "CLUNK" when I put it in reverse. with wire unpludgged - sooo much nicer.

 

[Itali83]

You need to shut the truck off after plugging the brown wire back together. Not sure why but every TBI truck I’ve got. I had to do that.

this is the sequence I use for setting timing.
Unplug brown wire, start truck, set timing, shut truck off, plug brown wire back in then start truck and run it.

try that.

Ben

 

[Jwernatl]

I saw that somewhere too. So, I tried that - no difference.

 

[bucket]

Someone may have adjusted the base idle screw according to incorrect (retarded) ignition timing. You could also possibly have a vacuum leak.

 

[Jwernatl]

Would anyone happen to have a diagram of vacuum lines for the '87 350 tbi? Im looking but, having a hard time with finding something definitive.

 

[bucket]

The TBI diagram is very simple.

https://www.gmsquarebody.com/threads/under-hood-vacuum-diagram-and-tuning-stickers.3520/

 

[Jwernatl]

Tha

The TBI diagram is very simple.

https://www.gmsquarebody.com/threads/under-hood-vacuum-diagram-and-tuning-stickers.3520/

Thank you, it was right on my truck under hood!

Found it AND found the the lines from the canister - two lines going to the tbi. both were disconnected.

 

[Jwernatl]

here's ZLA emission/vacuum lines sticker off my 87CHEVY v10 350...