Edelbrock 1406 problem

[1979C20]

My brother is experiencing what I believe is a carb problem. He has a 77 C20 with a stock, original 350 stock intake, spreadbore-squarebore adapter, 1406 Edelbrock carb. The motor is tired. Not sure how many miles, it blows a good bit of white smoke on start up and uses a good bit of oil. He said he was driving down the road and his exhaust sound went from being smooth to being choppy at 45. He didnt hear any pops, cracks, snaps, bangs, clunks, etc. It started driving like crap and had no oomph. I jumped in and went for a ride to listen to his problem, it sounded like it was starving for air or fuel and like a missfire. His fuel filter was beyond filthy, so we bought a new one. His set up is the original solid line off the pump cut just below the alternator, rubber line, fuel filter, rubber line into the carb. About 1-1 1/2ft of rubber line. When I pulled the line off the filter, the was a bunch of pressure in the line and it sprayed fuel all over the engine bay. I pulled the "In" line off of the filter, so I figured it was clogged and built up that much pressure. I put the new one on and it drove a little better, but still sounded like a missfire. So I checked his spark plugs. #2 and 3 were badly gummed up with black grease like residue, but #5 and 8 were burning alright, so I know that that intaje plane isnt too fat. I replaced those 2 plugs with the same typr, and I also replaced a bit of the rubber fuel line because it was the wrong size and pretty dry rot. When I went to pull the rubber line off the fuel filter again, it had a bunch of pressure built up again and I got sprayed with fuel and it got in my eye. Not pleasant, it burned and made my eye numb. So, im thinking that the built up pressure in the line is pushing fuel past the needle and seat and flooding the carb causing it to run like crap. Sorry for the lengthy post. Just trying to get the details out. Is there something inside of the carb that can clog causing the fuel pressure to raise in the line and flood the carb? I pulled off the fuel inlet at the passenger, rear, top of the carb and I saw a snall, like 1/16 of an inch diameter mesh tube and it looked clean.

[78 Chevyrado]

Does he have a fuel pressure regulator?  If not he needs to get one.  Edelbrocks REQUIRE one.  Set it to 5psi to 5.5psi.  The stock mechanical pump puts out 7-8psi If I remember right.  I had those sorts or problems until I installed my regulator on my 1406.

I have this one
http://www.holley.com/12-803BP.asp


As for the pressure still in the line, It will still be pressurized until either the gas finally leaks down past the needles or the diaphragm in the fuel pump.  this is normal.

Are you using the stock metal fuel line from the pump to the carb?  I had to put insulation on mine to stop it from vapor locking all the time.   

[bake74]

     As 78 Chevyrado stated, get the regulator.  I know what you are going to say ( I hear it all the time at work, everyday), it has been working without one for (insert time here). 
     That might be true, but it does not change the point that it should have one to be right.  Also as stated, pressure in the fuel line is normal, and 7 psi is a lot of gas pressure if you are just pulling it off.  Next time open the throttle body on the carb. a couple of times with the truck off to release the pressure so you don't get it into your eye's. ( where's your safety glasses ? )
     The other point I want to make, sounds like your brothers truck could use a good tune up.  With the symptoms you are stating, it will need a tune up more often than normal, just due to the fact it runs poorly.  The misfire could be from spark plugs.  Even though you cleaned them does not mean that they still are good.  (the core inside could have shorted out from being so dirty, shorted out internally and you would never be able to see it from the outside).  Wires would not be a bad idea either.

[ralphhemi]

 some Holley  carburetors have a filter in the carburetor where the fuel line is attached to the carb. Remove the fuel line than use a 1 inch. wrench and remove that fitting.   

[1979C20]

We replaced the bad sparkplugs. Would adding a fuel pressure regulator fix the constant stumbling problem he is experiencing. It sounds like when a truck that isnt tuned right, when you start accelerating hard and its got a little hesitation. But, his truck sounds like it all the time.

[1979C20]

Cap is new, rotor is in good condition, coil is new, spark plugs are all about 2 months old except for the 2 I replaced, they were burning nice for the first few weeks they were in. like a perfectly roasted marshmellow. The timing is set to 8-10° btdc, the vac advance is hooked up to full vacuum, but I tried it on the timed vacuum with no change. Good fuel pressure, good spark, firing order is correct, the exhaust manifolds are all hot, they evap water on contact. No vacuum leaks that I can find. The torque converter is going out. When hes accelerating half pedal and up, when the trans shifts theres a loud "Zzzzzzzzt" noise, it sounds like electric hair clippers. So what would you guys recommend for the constant hesitation? Just a fuel pressure regulator or do you have any other ideas?

[1979C20]

Alrighty! I figured it out! When the truck didnt run any different after the 2 new plugs, I figured it was the fuel pressure issue, or maybe something wrong with the carb. So today he brought his truck over and I looked down inside the carb to see if fuel was seeping out of the venturis, and it wasnt, so I ruled out the carb. Then I noticed his number 3 plug wire was off. Hooked it up and its running normal now. So I was right that it was a missing cylinder, but I messed up by not putting the plug wire back on. Haha. Ill still have him get the pressure regulator so there isnt any issues later down the road. Thanks guys, sometimes the only help you need is to recheck your work.

[bake74]

     Glad to hear you got it fixed.  Also nice to hear you are willing to help out your brother so much.

[buddyboy]

I run same carb on my engine , never had any issues with fuel pressure , with stock fuel pump or the edelbrock pump. when I  first got truck it had stock intake with adaptor for the 1406 and it ran good .then I swithed to edelbrock duel plane intake and was a big improvement.

[VileZambonie]

My first thought was you had a wire off. I just had this happen to me a few weks ago in my K20. Temp changes with an older set of wires they can slip off especially if they're around headers. You need to be carefull just popping fuel lines off like that and spend two bucks on a pair of safety glasses. Would you pay two dollars to see if you were blind? We do stupid things all the time so just slip a pair on. Harbor freight sells a pair for $1.49 that you can't even tell you are wearing and will forget you have them on. Please be careful!

[1979C20]

I have a pair of safety glasses I just have to find them, and the first day I went over to his house so the only tools I had was whats in my toolbox. Me and my brother are pretty close, but hes not as mechanically inclined as I am. He doesnt have a job right now, so I know he doesnt have them.money to take his truck to a shop. I have enough of an understanding on how our trucks work so I help him out with everything I can. Besides, I really enjoy working on trucks, so I help out everyone around me. Besides, theres nothing I cant do or figure out how to do with help from this forum.