Tune Up Direction

DPOK

New Member
Jun 28, 2020
17
I suspect this will all sound pretty basic, but it is where we are at.

We are getting our 81 back on the road after it sat for a long time. We have replaced everything from the gas tank to the carb with the exception of the hard lines. We rebuilt the carb, replaced the vacuum lines, replaced the plugs, cap and rotor. The plug wires are a few years old, but have literally a few miles on them and they look new.

Our two problems are that after it warms up a little, the idle is so slow that it wants to die if you don't give it a little pedal. Also, it is in the garage and the gas smell is pretty strong after running it for 4 or 5 minutes (nose in with the garage door open), so much so that it burns your eyes a little.

We have a timing light with a tach and a pressure gauge to use (although the car doesn't look like it has timing marks).

I don't want to do anything out of order and we are at a bit of a loss for tuning the carb. It is a Holley and I can grab the model if that would be helpful.

It would be helpful if somebody could give us some do this first, this second, this third kind of direction to get us started.

Thank you for your help,
Dave
 

DPOK

New Member
Jun 28, 2020
17
I didn't think in that way, but would be interested in that and would hopefully have something to offer in return. I am in College Station, TX.
 

ssupercoolss

Veteran Member
Nov 3, 2015
1,117
PA
i would start by adjusting your idle mixture screws. here is a good read.

might have 2 or 4 screws depending on the carb. use a vacuum gauge. make small adjustments, listen to the engine, watch the vac gauge. we will assume for now that your timing is ok.
 

tom3

Veteran Member
Aug 1, 1999
14,631
ohio
Did that 81 have a feedback Qjet and a computer to set timing and mixture originally? Have you replaced the distributor? Sometimes that eye burning mixture is actually a lean condition. I'd start by looking for a vacuum lean, then go with the carb adjustments as above, then dig out those timing marks and see what's going on there.
 

DPOK

New Member
Jun 28, 2020
17
Thank you for your help. It has been some time, but we followed the directions on your holley link and the car is running better than ever.

Still, I wouldn't mind checking the timing just in case we could dial it in even better. Are there different choices for timing marks? We don't have any attached to the timing cover.

Thanks again for your help.
 

need-for-speed

Veteran Member
Feb 7, 2003
1,270
Conroe, TX
First of all: College Station…
WHOOP ! Class of ’86 here!

EDITED:
Well that sux if there’s no timing bracket on the timing chain cover. You may have to add a tab as mentioned in post 8 and go through the exercise of finding TDC. This vid shows how to locate TDC. IIRC it doesn’t distinguish between TDC on the compression or the exhaust stroke. You’ll have to verify that its on the compression stroke. Set the timing with the vac advance disconnected.
 
Last edited:

grzewnicki

Veteran Member
Lifetime Gold Member
Dec 9, 2009
3,689
Gordon from Jacksonville Fl
Basic rule; dwell, timing, carb. dwell affects timing and timing affects carb. Taught that in 1979, gotta figure it still stands today, of course you got HEI so dwell is set for you. Can buy an aftermarket timing tab to bolt on, and some MSD balancer tape to get the timing set.
 




Top