need help-engine barely starts when warmed up

Ignition modual maybe The VV carbs are pretty foolproof. It's all the crap they stick on them to get them to idol correctly. Check your fuel pressure with the system hot and with it cold.and then make sure the timing is close, if not right on. You could do the "rev the engine with the air cleaner off and toss a big rag onto the top of the carb." That sucks the crud through the fuel ports in the carb. Remember to remove it afterwards. Really sounds like it is starving for fuel. Thus the vaporlock thing I mentioned. Other than that, I can't think of a thing?

 

Dave have you bypassed your fuel supply , but make sure your timing is correct first we often remove all the polution garbage on anything after 1976 . good luck from downunder

 

The engine generally runs a bit rough as well. As I drive down the road, I can feel the car jerk very slightly, as if the carb is not providing a constant amount of fuel. I will check the timing, although as I said earlier in this thread, there is a sticker saying that the timing is not adjustible, plus there is a metal box which will make it difficult to access the dizzy hold down nut.

 

sounds very much like a fuel problem i had one years ago that ran on leaded fuel when we went to total unleaded its our belief that breakdown of lead deposits in the tank/supply lines created my problem , good luck from downunder hope its sorted for you soon

 

Timing

Sonny leave the timing along and throw that junk carb away

 

I would love to know what that box is at the base of the distributor. I have a funny feeling it is part of the barometric pressure compensator system. How many leads are there on your ignition control module? Are there 2 plugs or 3? If 3, that is the one with the barometric pressure sensor beside it, and that box is part of the early timing adjust set up. If I am right, there is also a knock sensor on the intake manifold. It may have given up the ghost. They are not hard to find or change. If the knock sensor is working properly, you will find a VERY light knock under heavy load. If you are getting no knock at all, on regular fuel, the knock sensor is not working right. The owner's manual warns that they are calibrated for light knock under heavy load.

There is one other way around this problem, but it means more work. Get the 351W distributor for a newer model, say 85 and up, that is adjustable easily. Eliminate the 'electronic' adjustor and knock sensor, and switch to a 2 lead ignition control module (The one for a 79 Thunderbird, for example). Then, set the timing for 12 degrees before top dead centre, and play with it from there. And do, for sure, eliminate the VV carb. Noone knows how that cockeyed system really works, and that includes the Ford tech support people! Get a carb set up for a 79 Thunderbird, LTD II or Cougar. All were available with a 351W and used the normal carb. If that works, you could then think of an Edelbrock Performer intake and carb. It works really well on these. Just talk to Edelbrock's tech support about which jets and metering rods to order with it. They are a snap to change with the carb off the car. You don't need to open the carb to do the swap. Then tune the carb properly, and you're good to go. Because your car has the carb kick down linkage on it, the Edelbrock 1401 body will work perfectly on it, and give fantastic fuel economy as well.

 

Mike I think you are getting to deep for Sonny

 

If swapping out to a "normal" carb I would go to a regular Ford DS2 ignition system.
Way simple, works reliably.

 

I greatly appreciate everyone's advice! I am going to start with just replacing the carb, and see how much that helps. MikeT - I will check on how many leads there are on the ICM and let you know. I will also take some better photos of the mystery box and post them here. Thanks again everyone!

 

UPDATE - I pulled out the cold enrichment rod and cleaned it off since it was a little gunked-up. Since I did this, I have not had this hard starting problem at all! However, the engine still runs rough, and I am planning on getting rid of the 7022VV carb. Here is a link to the August 1976 edition of Popular Science which contains an article on Ford's "new" Variable Venturi carburetor. Pretty interesting graphics.
http://books.google.com/books?id=EgE...%20rod&f=false

 

I know your pain with the vv carb system my brother had that on an old ltd. I think you could be right on the timing not being adjustable at all on that motor as there were two versions of distributors one had a key way that locked it in place and made it so it could not be adjusted at all. But we worked on it for a couple of days and when it was done it ran real strong. A little tweaking on some of the adjustment screws on the vv. $50.00 dollar car $50.00 worth of tune up parts and drove it for two years. It actually ran great. Dont know where it ended up after it was stolen, yep stolen a $50.00 car. Only in America....And this is what I looked like when I found out :dancingparty:

 

Me personally I hated that car

 

Take the vv carb and replace it.IF you have run the new plugs you installed with that carb malfunctioning and drown them out even 1 time,BEFORE YOU TOUCH ANYTHING ELSE replace the carb and PUT NEW PLUGS in it again Start it up clear it out (a good long drive honk on it a few times) and then consider any other suggestions here!


Another thing CHECK YOUR OIL! Smell it see if it smells like gas and change it if it does.My vv carb had about 2 gallons of gas in my oil pan when i got my 79!