Cold blooded 1973

I am going to preface with the fact that I don't even have this truck yet, getting it this weekend.

1973 302 Holley carb manual choke C4 

When I purchased it in 1987 it was always cold blooded.  It has been parked for many years and I am getting ready to bring it back to life.

My plan it to clean the entire fuel system and rebuild the carb, R/R distributor, plugs, wires and anything else I can think of.

My question is would an upgraded ignition system help with the "cold blooded" or is that a fuel issue?  Manual choke upgrade?

Thanks....

Is the "Heat Riser" system still installed?

 A manual choke will help, but a remanufactured carb will take care of the choke problems which are not addressed by a rebuild kit.  However, especially in areas of the country that get chilly or cold, the heat riser system that came from the factory needs to be installed to get good start and run characteristics.  Not being real familiar with the early Bronco's, I don't know what came on them.  The heat riser system feeds warm air and recirculates a small portion of the exhaust to the intake when the engine first starts.  As the engine warms up, the exhaust recirculation is shut off and continues with warm air off the manifold untill the engine gets up to normal operating temperature.   Some engines had a heat sensitive spring valve on the exhaust manifold for the exhaust recirculation and later they went to a vacuum operated pair of valves controlled by a VCV tapped into the water jacket.  The warm air from the manifold is controlled by 1 or 2 sensors on the Air Cleaner which control a vacuum motor located in the scoop which opens or closes based on the air temperature in the Air Cleaner.

Attached is a diagram for an 85 351W so you can get an idea what you might want to install.

The orange lines go to the Heat Control Valves which are controlled by that VCV at the bottom right with the red lines on it.  That VCV usually shuts off the exhaust recirculation when the engine gets up about 90 degrees F.  The effect of these sysyems is to help vaporize the fuel better and prevents ice from developing in the intake when it is cold. The intake air comming in through the carb  when the engine is cold is at freezing temperatures.  Cold air is not always what you want especially untill the engine gets up to it's normal running temperature.  If you are a pilot that flys normally aspired engine airplanes you will be familiar with the carb iceing issue, not normally understood by car drivers.

The Air cleaner warm air is controlled by the valves shown at the top left called "A/CL BI Met" and "A/CL DV" which are hooked directly to the Main Vacuum tree.  There is usually another one called an "A/CL CWM" (Air Cleaner Cold Weather Modulator) in series with them, not shown in that picture but in the small picture that zeroes in on them.  The BiMet and Modulator are mounted on the cleaer and the DV (Diverter Valve) is on the intake snout.  A lot of people rip these off thinking that they are part of the polution control system, but they are not.  They are there strictly to give you good start and run characteristics, that is if the component parts are functioning.  The main problem I find with them is that the HCVs (Heat Control Valve) tend to get carboned up after years of use, but if maintained they work just fine.  

Hope that little bit of bla, bla, bla makes sense.

P.S.

Here are two diagrams.  The first is a complete diagram for an 85 351W with polution controls, the second only shows the portion of the system that is there for start and run.  The black lined pirtion is for venting the fuel tank on a dual tank installation, a single tank system would eliminate one purge control vvalve and one carbon canister, (not part of the start up heat control).

I know the Land Cruisers had the heat risers but don't recall if the EB's had them. If they did, they were gone when I

took posession of the rigs. (headers & other mods)

However, it's unclear what you mean as "cold blooded" ..?

Do you mean hard to start.., or once started, sluggish & hard to get going..?  (Or both)

In proper tune, these rigs should start & purr (ever in cold weather) with a couple pumps on the throttle & the hand choke pulled.

If not, the accelerator pump may be shot, the idle circuit dirty, choke not moving, or in some cases, the

timing way off. Maybe even a vacuum leak, or a combination of these.

Slow to warm up.., could be a stuck T-stat, or it's not in there.

Thanks.  I haven't even looked at the timing yet.  I installed an Ignitor ignition and the coil was wired backwards.  Ignition to the Neg side of the coil and points on the positive.  I have installed a new coil and wired it to the diagram that Pertronix sent in the box.  Is there an ignition resistor in the bronco?  I haven't been able to find one.

"--Is there an ignition resistor in the bronco? I haven't been able to find one"

If you look at the + wire to the coil.., it should look fat/swollen so to speak. Usually "red".

That would be a "resistor wire" as I believe they eliminated the ballast resistor by '73

(This wire drops to 6V as well)

It's possible the pertronix  ign. runs on 12V   i.e. no resistor or resistor wire.  Might want to check that.

(My GM HEI runs on 12V)

The wire to (+) is a pink/green and looks to be "normal" size.  

The resistive wire doesn't go right up to the coil, it is bundeled up in a cable lace.  Attached is a typical Duraspark II diagram.

Good luck,

>-

Then the thing to do (I forgot to mention) volt-meter that wire with key on.

& again, what does Pertronix say to run it on --- 6V or 12V --- ?

It needs 12v key on.  I wired the positive lead to the Pertonix to the green wire the fed the solenoid to the original carb.  Since someone replaced the original carb with a Holley the green wire was not being used, so I spliced the wires together and the engine is starting and running very well.  Does anyone know if this is an OK wiring plan or should I find somewhere else to hook it up?

COLD BLOODED ISSUE IS GONE!!!  This morning I stuck my arm in the window and turned the key and it fired on the first crank.  This truck has NEVER run this well.....  I am sooo happy.

Sounds like real progress / ,  Any place you can get 12V key on will do for a Holley.

>-