Ok so I have an 86 TA and its having some trouble. Now, very little about this motor is stock. There is no ECM, fuel injection, etc. Its a 74 350 block bored 10 over, scat forged steel crank, comp xtreme energy cam, stock heads, full roller rockers, edelbrock performer intake, edelbrock 650 carb, hooker headers, stock hei distributor base with msd cap & rotor and accel hei super coil & control module, 8mm accel wires, and accel shorty plugs.

The issue I'm having has been around for some time. I've been trying to track it down so when I upgrade some stuff I replace the right thing first. At an idle I have a misfire, like a rough idle, and when accelerating at low rpm it bogs down and sputters unless I advance the throttle till the secondaries open then it kicks down and runs like a beast. Once the car warms up the bogging down gets better. Also there is a chuffing sound from #8 cylinder, like an exhaust leak (but I've changed all of the gaskets and inspected the header for cracks and found nothing). Now I have tried adjusting the timing and fuel mixture to no avail. I've even gone as far as adjusting each one of the rocker arms to make sure one of the valves wasn't out of adjustment. It runs the best when its rich, but the idle never smooths out.

So I've been doing some reading trying to make a list of possibilities.
-The chuffing makes me think possibly a burnt valve?
-Vacuum advance cuz the distributor base is pretty old?
-Gummed up primaries on the carb?

Oh and I have tried some simple things to narrow these down.
-Dollar bill by the tail pipe - Couldn't tell, or the suction wasn't strong enough
-Carb cleaner - No change
-Cleaned up spark plugs - Ran a bit better, but no irregularities at the look of the plugs
-Checked plug wire seating - Had some loose wires, but after fixing them no noticeable change
-Checked for vacuum leaks - None found
-Tried cleaning the intake with Seafoam through the vacuum lines - No change

Any other ideas? Any help I can get would be great, I can't do alot at one time as its my daily driver, but I do have the weekends. Thanks!

 

If it has the stock distributor then it is computer controlled and it will cause issues.

Make sure you get a regular distributor with vac advance.

Other things to check and do.

Tighten the header bolts.

Check timing

Get vacuum gauge and tune the idle circuit and swap the rod springs.

 

It is an HEI distributor from late 70s I believe.

I tightened the header bolts according to the whole tighten, warm the motor up, tighten again, etc.

What do you mean swap the rod springs? I am planning on getting a vacuum gauge and mounting it on the pillar, but I will see if I have one just to check the vacuum for now. Do you know how much it should be at? (The only vacuum I have really dealt with was an old ford straight six.) And do you know a good method to tune an edelbrock carb besides its stock screw it in all the way then back it out a certain amount setup? I tried that and ended up just trial and error testing it till I got it to run decent.

 

What is your timing set to? Are you using the vac advance?

You want to adjust the idle screws to get max vacuum.

Here is a decent write up

http://www.fordmuscle.com/archives/2...ockCarburetor/

After you tune the idle screws take your idle vac value and divide by two then install springs of that value.

 

I am not sure at the moment, I was messing around with it earlier. Yes, I am using the vacuum advance.

Wow, thats more in depth than I have ever gotten with this carb. Do you think its worth doing all that work on? I was planning on getting a new carb (a street demon or holley) cuz I figured this one is so old and has been rebuilt who knows how many times. How much does that rod and jet kit cost? I do have more time than money..

 

Nothing really wears down in a carb that is not replaced during a rebuild. Rebuild a carb is about $30. Is your accelerator pump squirting?

Again what is your timing set to?

 

Timing is at 7 degrees before tdc. That seems to be where it runs the best.

That is a good question, I will take a look at that.

 

Ok so what is the TOTAL timing how many degrees at what RPM. 7 is way to low for initial timing. You should probably be running 12 ish at idle and 36 at 3000.

 

Ok so heres an update. I found a spark plug wire not all the way on the distributor cap. Also, the electric choke was a little sticky. After fixing that and messing with the fuel mixture I got it to run like a champ. It drove great, ran smooth, and the idle was almost perfect. Then, after a few days of driving the idle just changed and it ran like crap for an entire day. The next day, it ran good again. Then today, it ran good going up to the store but when I went to leave it started fine and ran good for about 10 seconds, then the idle changed again and it ran like crap. I thought the choke might be hanging up but it seems fine. Then I noticed I can see bubbles in my fuel filter (it is between the tank and the mech pump) coming back from the pump. So I'm wondering is there something wrong with the pump? Or are the filters just getting dirty?