Hey there I`m new to this club, but I figured If anyone can help me it`s a bunch of blue oval guys.Here`s the prob. Got a 1980 f150 4x4 with c6 auto & 351M. well for a long time after I bought the truck used , on cool\cold damp days only in the morning, the engine would start to lope & the idle drop off to nuthin at the first stop light.Now being a mechanic I checked all the usual stuff wires vaccuum , chock settings all the usual stuff. Well here`s the strange part. since the motor was tired, I dropped in a new long block right from ford.EVERYTHING was replaced. Dist & box, carb (now 600cfm holley)& man choke wires, coil , alt,fuel pump,int manifold (Weiand), starter modulator valve,plugs, absolutely everything is new.Guess what SAME PROB.Talked to Ford, Holley, Hot Rod , & lots of others NOBODY KNOWS.Truck runs great pulls real good just still has this idle prob.Sure hope you guys can help It`s drivin me nuts Thanx freedomrider

 

have you disabled all the ford computer stuff? I'd suggest an MSD 6 box to get rid of the ford wiring

 

Welp this might sound strange but I had a VW Bug that would do the same thing. On cool/cold damp mornings/nights if the engine had not been running for a couple of hours the damn thing would just lope and die. Sometimes it would take 20-30 minutes to before it would idle at all. But it sure pulled like a raped ape (for a bug that is). After owning the car for 5 years and replacing the engine 3 times (I could pull the motor by myself in 20 minutes) the problem never went away.

One day I was giving a buddy who was majoring in chemical design engineering a ride to school. I was sitting outside his home revving the engine and thoroughly pissing off his wife (old bugs sounded great with zoom mufflers lol). He comes out and asked why I had revved it for (he knew I didn't like his wife to much) was it because something was wrong with "Killer" or just to **** her off.

I explained to him the story, third engine; different carbs, yada yada yada and it always ran like this. The first thing he said is that it was icing up the intake manifolds and vapor locking inside the intake. I told him he was full of stuff and bet him a $50 and night of drinking if he could prove it and fix the trouble.

A couple of days later he comes over and we start Killer up. It ran for maybe 10/30 seconds and died. He then pulled both carbs off and sure enough there was some moisture on the intake runners. As the carb is sucking in moist air and mixing it with the fuel, the fuel is acting like a refrigerant. The fuel is “flashing”, removing the heat from the incoming air, and expanding in the intake (vapor locking the intake).

This cooled the moisture trapped in the air enough to make it ice up on the inside of the intake runners. I was running two Moroso Velocity Stack air cleaners on it at the time so to help fix the problem we split a ½ “ copper tube on one end strapped that as close to the exhaust port on the header as we could. We attached the tubes to the stacks by drilling a hole into the stacks and soldering the tubes to them. This allowed the engine to pull just enough hot air off the headers to stop the thing from icing up.

If you don’t have a warm air pipe hooked to your exhaust then you might be having the same troubles. Worth a shot anyways.

 

Wayne has the right fix.

It is called carburetor icing and aircraft flight engineers on piston engine planes have to fight it all the time. It happens whenever the humidity and temp is right. The first time I ran into the problem was on my 64 F100. I had checked everything also, but I did not do much replacement beyond points, condenser, rotor and coil. When the engine stalled for the hundredth time I moved very fast and pulled that air cleaner just in time to see that frost flash over to dew then vaporize. I fixed it by putting on a heated air intake off a more modern truck. The second time was on a 68 VW. There I just pulled my winter carb air intake off of the heated cooling air blowing off the cylinders. I knew what the problem was that time. I now use factory GM 454 or Chrysler 440 air boxes with dual Ford fresh air snorkels.

 

Yep thats what I had to do on my 78, get some warm air up there and she did great.

 

Your all right it is moisture in the intake. My Truck gives me the same problem. When you atomize fuel the intake and manifold temeratures drop this causes the moisture in the air to condensate on the intake runners. To further amplify the problem the fuel itself is cold and thus does not stay in suspension and also condensates in the manifold. Engines can't burn liquid fuel it must be atomized. so now you have water and liquid fuel entering the combustion chamber and it can't be burn't this is what causes "load up" and bad to no idle. To fix this you need a way to keep the carb and intake warm enough to keep water and fuel from condensating in the manifold. Hope this helps!

400m

 

Throw away those fancy chrome air filters! They don't do any good except look purdy on a trailer queen.

Get yourself a big GM 454 truck air box with the big 12" OD x 5-1/2" tall filter and stick a K&N E1420 in. If you haven't got space for that there is a chrysler 440 motor home unit that is 3.5" tall or other shorter GM units. Ford constipated their engines horribly in the intake air department as a poor man's rev control. Install dual Ford Air box snorkels with vacuum motors and a modified thermostatic vacuum switch to regulate the incoming air at about 75F. Tee the switch to both vacuum motors. Build or use hot air boxes around the headers or manifold on at least one side and block the other hot air intake if unused. Pipe in fresh air ducts from the radiator support as smooth and large as possible.

This will solve a lot of winter AND summer engine problems!

 

man sure appreciate all the help.checked it out & yup there`s the demon "frost ". I also had a VW, when I was a kid, a 61 & now that you mention it I remember a carb frosting prob on that beast. Forgot all about it Guess that comes with age lol.thanx again for takin time out to help.

 

[updated:LAST EDITED ON 18-May-02 AT 08:11 AM (EST)]Hummm Funny how a lot of us that have owned a VW bug in the past now drive a Ford truck. I wonder if it's something in the water?

 

Something in the fumes I think

Or maybe the pure simplicity of those old VW's

 

 

SIMPLICITY, that's it. I'm trying to get a VW bug off my neighbor right now, as he has several. But his dang relatives keep mooching them, and I'm at the end of the line.

 

Yes! KISS! Keep It Simple Stupid, -Absolutely the best policy. The old VW's had that one down to a science:-) I still have the engine (mothballed), tranny, rear suspension, and a lot of other pieces out of my old 68. One of the old repair manuals was great. Included in the instruction for the proper starting sequence for your VW was: After starting the engine take a break and "roll your own" B4 driving off as part off the warmup. And they weren't talking about Bull Durham either. Obviously written by an old Hippie.