• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Holley Secondary's won't open

tarafied1

tarafied1

Well-Known Member
As long as the engine is apart I thought I would dig a little more into my carb issue. I have a 18 year old Holley 770 Street Avenger vacuum secondary. After my disappointing low 13 second passes at the track I have verified the secondary's won't open. I used the paper clip on the linkage and it didn't move. I bought a new diaphragm but when I pulled the housing off before splitting it open, I checked it with my vacuum pump/gauge and it works. So I replaced the little gasket between the housing. Blew some carb cleaner back thru the hole and verified the passages are open. I put it all back together and it still didn't work.
Since I can't road test for a while and it's off anyway, I tried blowing air thru the venturi above the small port. Stiil didn't work. I replaced the diaphragm with the new one anyway, still didn't work. I took the no color "out of the box" spring out and put a yellow spring in (lightest). Still didn't work. Took the spring out completely and it moved but didn't open. I have an old 750 on the shelf so I checked it the same way. It worked. I swapped the housings between them and the 750 will work with both but the 770 will not work with either.
Any ideas what's wrong with the 770?
cQjNOVx.jpg
 
Mach1Rider said:
Did you see the check ball in place? without it it will not work.
Click to expand...
the check ball is there. What's weird is I can swap the whole diaphragm housing assembly from the 770 to the 750 and it works on the 750. I can take the working assembly from the 750 and it will not work on the 770.
If I take the spring out completely, the 770 secondary's will try to open so it's not binding. I can manually move it freely. It seams like it's not getting the pressure drop to create the vacuum needed to open the secondary's.
 
If the gasket is not blocking the port, Then run a thin wire thru it to see if has some sort of obstruction.
Yes I saw where you cleaned it with spray and air but any drop in vac is not the same as liquid or compressed air flowing.
It works on the 750 but won't work on the 770, the problem is in the 770 passage.
 
Mach1Rider said:
... the problem is in the 770 passage.
Click to expand...
that's what I am thinking too. It doesn't look like a straight shot but I will try a thin wire and see what I can do. thanks
I may also take it all apart and buy a gallon of carb cleaner and soak it
 
SWMBO doesn't let me get a word in edgewise at home so I try to make up for it here. You guys got an issue with that? My typing out extended, unnecessarily long posts? I suppose I could try and cut back on the volume of words I use. I will try and keep that in mind from now on now that you have made me aware of what might be considered a forum breech of etiquette. I really didn't mean to offend or take up valuable post space. Promise to try and do better. I will. Honest. Starting right now.
 
Horseplay said:
SWMBO doesn't let me get a word in edgewise at home so I try to make up for it here. You guys got an issue with that? My typing out extended, unnecessarily long posts? I suppose I could try and cut back on the volume of words I use. I will try and keep that in mind from now on now that you have made me aware of what might be considered a forum breech of etiquette. I really didn't mean to offend or take up valuable post space. Promise to try and do better. I will. Honest. Starting right now.
Click to expand...
you're good, just messing with ya.
By the way, here is a little video of the issue
 
Horseplay said:
SWMBO doesn't let me get a word in edgewise at home so I try to make up for it here. You guys got an issue with that? My typing out extended, unnecessarily long posts? I suppose I could try and cut back on the volume of words I use. I will try and keep that in mind from now on now that you have made me aware of what might be considered a forum breech of etiquette. I really didn't mean to offend or take up valuable post space. Promise to try and do better. I will. Honest. Starting right now.
Click to expand...

Jesus, just shut up already.
 
Patrick Stapler said:
Ditch it and get a DP
Click to expand...
I have been thinking about that. The car weights 3400 lbs. It has 3.25 rear gears. Right now it's a C6 with TCI 2400 stall converter but I will be switching to a TKO 600. Honestly I have never had a car with a double pumper. I have heard they can be really tricky to get the size and tune correct.
 
tarafied1 said:
I have been thinking about that. The car weights 3400 lbs. It has 3.25 rear gears. Right now it's a C6 with TCI 2400 stall converter but I will be switching to a TKO 600. Honestly I have never had a car with a double pumper. I have heard they can be really tricky to get the size and tune correct.
Click to expand...

Not if you're willing to spend a little extra and get a custom setup!

I bought a custom 650 dp back in 08 and all I've done since is change the squirters for the new engine.
 
You must log in or register to reply here.
Back
Top