Insane Fuel Delivery "fail" -- DESPERATE

[virginwidow]

NOBODY around here has a clue.

 

It's a '79 620, sadly from California (I will never buy anything from there again) with the stock carb and all the other foo-tard crap (a whole bunch of vacuum lines and hozes and relays and sabotage)

 

What it does:

 

1.   There is fresh gas in tank

 

2. The Fuel pump runs.

 

3. Filters fresh, lines clear.

 

4. The fuel squirts eagerly from the line, taken loose as close as I can get to the Un-Carb.

 

5. The truck starts for 2 seconds on ether, electric is fine.

 

6. Had my kid keep his hand on the pump, while Fail-Starting -- the pump IS NOT CUTTING OFF (it's not a fuel PUMP relay)

 

So --- can someone please explain to me how the FUEL is NOT getting to bowl?

 

I know it has to do with California and 1979 (everything built after 1972 is fooobar... ) I want to know HOW to get the damn gas TO the carb (ie, go around whatever SABOTAGE is stopping it)... The truck was running okay-ish before what I first thought was a vapor lock -- then I realized no -- vapor lock wont start at all. It was starting WITHOUT ether, and then shutting down within seconds.

 

meaning, the DEMONIC force Within allowed it to start, then "realized its error" and cut the fuel. Now it wont let the fuel through at all.

 

yes I have a Holley 240 I can pull off the green truck -- but I've looked at the way the throttle cable runs not sure I'll be able to hook it up

(the holley is coming off a '76) and also there is (WTF is THAT crap for???) a fuel line running from engine back to tank -- I mean -- ??? WHY. If the carb is jetted adjusted right NOTHING is left over?

 

I don't want to go making matters worse, not knowing what OTHER booby traps are set with the intent of preventing a rational owner from removing the STUPID from their truck.

 

I'd love to just gut this nice body (I bought it for lack of rust) and stuff the good parts off the '76 in it, nicely like everyone else here does.

 

I just dont have that kinda coin.

 

ANY clues? WTF is stuck in the gas line (there is less than 16" that is full of U turns between the point I checked and the bowl) , or HOW do I get the gas INSIDE of the carb? Or for real, yank the Hitachi off and be done?

 

THANKS

 

vw

 

[Draker]

79 had an electric pump? Shouldn't it be mechanical?

[datzenmike]

The '79 had an electric fuel pump if it had air conditioning.

 

The return line is essential for good running in warm weather. The fuel pump merely fills, and keeps the float chamber full of gas. This is all it does. The carb removes gas as needed. The pump replaces it. When very warm the gas not used by the carb can get hot enough to boil into a vapor making running and restart very difficult. The return line has a restriction in it but allows a small amount of fuel to constantly be returned to the tank. This recirculation keeps fresh cooler fuel in the line to the carb.

 

 

 

Look on the front of the carb, there is a small round glass with a dot on it. Fuel level should be at the dot. Is it???

 

 

NO.... float is stuck holding the needle valve closed, no gas can get in. Needle valve is blocked or stuck.

 

Where the gas enters the carb is called a banjo fitting. Loosen and lift up and off carefully and you will expose a brass or plastic fine mesh screen that may be plugged. The Banjo fitting sits on the fitting holding the inlet needle valve. Unscrew and you should be able to shake it out and examine it. Below it is the float arm. The float moves down as the fuel level drops, allowing the needle valve to open and let more fuel in. As it rises it closes the needle valve.

 

To access the float remove the three screws holding the front cover holder on and lift away. Now carefully pry out the front cover to expose the float chamber. Have a care as there are tiny parts that can fall out. Suff a rag under the carb front to catch anything.

 

If it was the needle valve or float you should have found something by now.

[kelowg]

Idle fuel cut off working correctly?? (Anti dieseling solenoid) try give it 1/4 throttle while cranking. Be sure elect.choke is working as well.

[virginwidow]

Thanks So much --

 

I think I can get to to the basics you've outlined without pulling the stock carb -- the rag suggestion is somewhat re-assuring, dad taught me that when I was a little girl whenever and however possible get a drop cloth under your work "the tiniest parts are the hardest ones to replace"... Guys at work just think I'm a wierd old woman.

 

I realllllly don't want to pull it, not lazy -- the trouble is, putting it back on --  how could I do that, with a perfectly good Holley on the other truck?

 

Your description on the return fuel lines interests me -- reflects what I've read in the manual. And it makes logical sense.

 

This begs the question: When I replaced a hoplessly broken hitachi (on my '78) with a Weber, no return line, ran great even in hot weather. There's no return on the Holley installation. Runs great -- if I had fuel vaporizing due to heat would there not be a strong gasoline odor? We never have return lines on S&S or Mikuni's (motorcycles) nor on any aviation carb I've met. 

 

I am not saying you're wrong -- what I'm getting at is every other 'Normal' carb I've dealt with, fuel doesn't boil. They're designed with the possibility in mind, to NOT BOIL. I'm now wondering -- if the Hitachi carb can boil the gas, the possibility so great an entire second fuel rail and all that (Follow the Money, manufacture, changes to assembly line, special parts) Were these Hitachi/Late stock carbs DESIGNED to boil the fuel?

 

My son keeps saying "Mom, it's an electronicly controlled carb" -- there are 4 wires running up underneath on the coil side, what do they do? They look like they were cooked some time ago. Do the crispy wires do anything that could cut the fuel? Someone here (in TN) said some of those old carbs had that "feature"

 

I'll put up some pics of the Holley install before I do anything rash. Were there not what appear to be significant differences in the way the throttle linkage goes, I'd have already changed it out

 

THANKS

 

vw

[Draker]

Anti-dieseling valve perhaps? 

[willz]

I know a couple of them go to the choke assuming you've got the shitachi on there. There are some instances where the fuel can boil, especially since the carb sits right on top of the exhaust manifold. High temperatures, sitting in traffic etc could cause the fuel to get to a vapor like state and make it difficult to restart or run well. Most motorcycles I've had with mikunis have the exhaust ports on the front of the motor with the carbs hanging out in the back. Not to mention they get a constant supply of cooler air than a non moving engine bay. I would suggest checking the filter on the banjo fitting as well as making sure the carb is actually filling with fuel. I can't think of any other restrictions in the line.

[willz]

I would say, take the banjo fitting off, I think it's a 16mm or something. Pull it and put it into a jug and click the key on. Gas in the bottle? Good. Check the screen on banjo fitting and if that's clear, I would consider cleaning the jets. That should take care of your problem. Then toss the hitachi and get a Weber lol

[tr8er]

The fuel rail gets hot because it runs right along the block. I don't think it's got anything to do with the carb choice, just the engine bay design. I'd expect this design would benefit any carb choice if the supply pressure and orifice were right for the carb. I'm not convinced this is your issue, but it's worth ruling out. You could simply shield your fuel line well and see if the run time extends significantly. I think you may be flooding instead of starving

[datzenmike]

The fuel return isn't on the carb so you can run any carb you like and still have the advantage of the fuel return.

 

Here's another advantage of the return.... ALL the fuel is eventually recirculated over and over, and this means any dirt or rust is caught in the fuel filter and does not accumulate in the tank.