1977 Cordoba 400 Edelbrock 4brl 1906 - LB delete

[Diesel01]

During my purchase of my Cordoba, I was told the Lean Burn was deleted and a new carburetor was installed. The breather has the LB module completely removed and metal tape is placed over the holes.

The Thermo-quad has been removed and an Edelbrock 1906 was installed. The car is running rich with black exhaust tip and black mark on the gargage floor. When it first starts, it lopes and revving it up seems to make it idle fine. On the road in my neighborhood, I have had it flood out to almost stall. I would throw it into Neutral and rev it up a bit and the gas would clean out.

I looked at several sites and 1906 seems to be sized right for my 400. Yesterday, I watched a couple videos on adjusting the fuel mixture with the two big screws on the front. One guy said start at 1.5 turns out. Mine are only a little over a 1/2 maybe 3/4 turn out.

I adjusted the screws in a 1/4 turn and it seems to be running better but I havent taken it out on the road yet. I am not smelling all the unburned gas smell as before but a more clean smell as what I remember.

So I am wondering if I have the correct size metering rods and was the LB delete done correctly? I have had now 2 times it load up with gas while driving to the point of flooding and almost stalling out. The electric choke seems to be free and working properly but did not check it when loading up.

 

[Don Frelier]

First make sure the choke opens quickly enough and fully when warm.
I think you need to take the top off and check the floats and needle valve and seat.
Seriously doubt richer rods would do what you've described.

I'd put a vacuum gauge on it. If the vacuum is too low and the metering rod springs are too stiff then the rods will always be in the up position.
But it sounds like way too much fuel at idle.
You can take off the metering rod covers press lightly and see that they move freely downward.
Another thing you can do is temporarily take the springs out of the metering rod holes.

Check the timing as well start with 10 deg. BTDC or more.

 

[Don Frelier]

If you have a phenolic carb adapter it's possible that the carb is not grounded.
Maybe the choke is not seeing 12volts?
Can't tell from the pictures.

 

[Diesel01]

I know this thing has set a lot so I am also wondering if it just needs to be ran and get a couple tanks of clean new gas through it. What type of fuel additive is recommended? Can I use STP for fuel injection? Maybe Lucus. I am thinking even though new, it is gummy.

 

[Diesel01]

If you have a phenolic carb adapter it's possible that the carb is not grounded.
Maybe the choke is not seeing 12volts?
Can't tell from the pictures.

There is both black and red wires going to the choke. I can test that there is 12v at the choke.

 

[Don Frelier]

I know this thing has set a lot so I am also wondering if it just needs to be ran and get a couple tanks of clean new gas through it. What type of fuel additive is recommended? Can I use STP for fuel injection? Maybe Lucus. I am thinking even though new, it is gummy.

If the air bleeds are plugged with fuel residue then it has to come apart get soaked and blown out.
Additive isn't going to cure it.

This would explain it.

 

[Don Frelier]

There is both black and red wires going to the choke. I can test that there is 12v at the choke.

The ground wire goes to one of the screws on the air horn of the carb.
But depending on the carb adapter it's possible you don't have a direct connection from the carb to the intake.
Maybe through the linkage but you don't want to depend on that.

 

[lewtot184]

Choke pull off may be sticking. Back off the black choke housing a little (counter clockwise) and see what happens.

 

[66fs]

Could be sticking open needle and seat if it has sat for an extended period with old gas.

 

[Diesel01]

Was it wise to remove the Thermo-quad? They were a good carb. The only issue I heard about them is if the resin body cracked or warped

 

[casey henson]

while your diagnosing you need to check your fuel pressure also. Most new mechanical fuel pumps are on the high side for some reason. 6 is max. really needs to be 4-5 psi.

 

[Diesel01]

while your diagnosing you need to check your fuel pressure also. Most new mechanical fuel pumps are on the high side for some reason. 6 is max. really needs to be 4-5 psi.

How do you compensate if it is too high? I have to get my vacuum/pressure gauge from my other garage this weekend.

One video I watched said to connect a vacuum gauge to the right plugged terminal in the front of the Edelbrock. Then tweak the left and right adjustment for max vacuum. I am wondering why one guy says to start at 1.5 turns out and mine are only a 1/2. Thats why I was questioning too small of rods.

 

[Diesel01]

Choke pull off may be sticking. Back off the black choke housing a little (counter clockwise) and see what happens.

Took it for a drive. Since I turned in the fuel mix yesterday 1/4 turn, it seems to be running better and responsive. Cold idle loped a little but not as bad. No flooding out or bogging. I checked the choke and it was fully open when up to temp.

 

[Diesel01]

The ground wire goes to one of the screws on the air horn of the carb.
But depending on the carb adapter it's possible you don't have a direct connection from the carb to the intake.
Maybe through the linkage but you don't want to depend on that.

There are 4 metal nuts that hold the carb down. I guess they could be composite studs. I would have to check ground with a meter.

 

[Don Frelier]

There are 4 metal nuts that hold the carb down. I guess they could be composite studs. I would have to check ground with a meter.

If the choke opens properly then it has a ground.
If you're at 1/2 turn or less from fully closed on the mixture screws then I would suspect something is blocking the idle air bleed.
Mixture screws and air bleeds are the only thing affecting idle air mixture.

 

[Diesel01]

If you have a phenolic carb adapter it's possible that the carb is not grounded.
Maybe the choke is not seeing 12volts?
Can't tell from the pictures.

If you look at my first front picture of the carb, you will see a black wire screwed down upper left and goes to ground.

 

[Tony Tee]

Almost the same situation with my 78 magnum 400. Previous owner installed a edelbrock carburetor. It ran rich. Ran fatter metering rods. But still ran rich. Then put in smaller jets. Twice! And it runs great. But I think one more jet change should be perfect.

 

[Diesel01]

Almost the same situation with my 78 magnum 400. Previous owner installed a edelbrock carburetor. It ran rich. Ran fatter metering rods. But still ran rich. Then put in smaller jets. Twice! And it runs great. But I think one more jet change should be perfect.

Yes it seems like metering rods or jets are wrong. Is yours a AVS2 1906? I am going to try this

Edelbrock Bog/Rough Idle

www.hotrodders.com

I am really thinking about putting the 9077S Thermo-quad back on it. You can get a rebuilt one for not too much.
Isn't there a chart somewhere to tell you what rods/jets work best with a Mopar 400?

 

[Geoff 2]

If you keep the Edel:
- remove the airhorn & check the float level. It is often incorrect. Should be 7/16". Unlike the brand H garbage, you will not need any gaskets if you are careful. Make sure needles & seats seal, seat is tight, floats do not bind & are not fuel logged. Once ready for install, invert the air horn & suck on the fuel inlet. If you can suck air, you have a leak with the n/seat.
- these carbs can work with 10 psi of fuel pressure; rarely is FP a problem with these carbs.
- I would adjust idle with the choke wired open to make sure it is not closing.
- I doubt you have a met rod problem because it 'revs up fine'. M/rods do not affect idle.
- once you have the engine idling, using a torch, look at the booster nozzles in the primaries. If you see fuel dribbling, it is flooding & the cause needs to be found & fixed.

 

[66fs]

Yes it seems like metering rods or jets are wrong. Is yours a AVS2 1906? I am going to try this

Edelbrock Bog/Rough Idle

www.hotrodders.com

I am really thinking about putting the 9077S Thermo-quad back on it. You can get a rebuilt one for not too much.
Isn't there a chart somewhere to tell you what rods/jets work best with a Mopar 400?

9077s is a 1977 high performance 400 TQ it should have 4098 primary jets, 5143 secondary jets, and 2159 rods (.070 x .062 x .040) should work perfect if in good shape. Not sure why you would swap out an 850 cfm carb for a 650 cfm carb. the TQ is one of the sweetest carbs ever made. Bowl problems are rarely encountered and easily fixed unless someone has messed up the primary jet inserts.