I have a Holley 4160 that is driving be crazy. At least I can say WHAT the problem is, so that is something.

The "off idle circuit" on one side, doesn't work. It idles fine mostly, but as soon as you crack the throttle w/a load, it drops 4 cylinders and turns into a V4; it only runs on the 4 cylinders fed by one plane of the dual plane intake.

While it's doing this, if you manually manipulate the accelerator pump, the 4 dead cylinder jump to life -proof that they're starving for fuel just off idle. Open the throttle more, and as soon as the main circuit comes on line, it runs normally.

This started a couple years ago, and I took the carb apart, cleaned/shot air/shot brake cleaner through all the orifices in the metering block, and put it back together...same problem. Took it in to work (shop) and several mechanics played w/it, poking wire through orifices, etc, and after that, it ran much better, for one summer. Now...it's back to the same thing. Took it apart tonight, and I'm telling you...the thing is CLEAN inside. No residue, no varnish, it's clean. I started blowing though every orifice again, paying close attention to the ones that feed air and fuel to the idle and off idle ports. Found no restrictions or debris.

Any ideas?


One other thing that is odd to me, is that in the throttle body, there are two holes, forward of the primary bores. One has a TINY orifice in it that connects to the left side idle circuit. I can fit one strand of a coper wire through it, barely. The other side is blocked off. I can't get shop air or a wire through it. Thing is, when mounted on the engine both those ports are covered/blocked off by the base gasket. Any thoughts on these?

 

There has got to be someone on this forum who has fiddle-f'ed with Holley's....


Well blew air and brake clean through every orifice in the primary side I could shoot stuff through. Then stuck wire in any hole that I thought wire-sticking might help.

Put it together this am, fired it up, no diff. I DON'T "GET IT". How can passageways that move air and fuel, stop working or "wear out"?? Grrr. Apparently, metering blocks for '06 and earlier 4160's have been discontinued too, which is BS. I'm pissed. I don't like Holleys, I don't "get" why in the world this thing won't deliver fuel off idle, I don't like Edelbrock carbs either so what do I do now? I want to understand why this thing won't work.

 

,njkllk

 

Did you adjust the idle air bleeds?

 

If you're referring to the screws on the sides of the primary metering block, yes, I have adjusted them. 100's of times probably. I should have posted that fact above so sorry for leaving that out, but another indicator that something is f'ed up is that I have them both backed out to the point where further adjusting does nothing. I'm just not able to get enough fuel to the engine at idle.

If I screw them in, starting at about 1.5 turns out, it gets even leaner and won't stay running at all (at idle, of course), unless I stroke the accelerator pump. Basically it runs the best if I back them out until they become ineffective.

 

Well....I have to say....little disappointed in my fellow 3rd gen'ers. Thought I'd get a solid 4160 schooling here.

Anyaway, I decided to try something a little unconventional. I wanted to try creating the same effect as an aqueous parts cleaner so I tool the main body, the TB and the metering block, and:
*Boiled them in water for a while
*threw them straight into the DISHWASHER with two soap pellets and about 3 cups of vinegar, and ran it for two hours.
*After I "chased" every passage w/brake cleaner and air (again).

Put it together, and fired it up tonight.

Ran smooth as glass.

 

it had to be something in the passages because it an fine then not, its just a matter of getting it out. i like those carb cleaners you get that look like a paint bucket, a real bad carb leave in in there overnight and i havent had one that didnt come loose with that stuff

 

in all my years working on carbs in general holleys are a "headache in a box" and yes sometimes one must resort to unconventional methods to clean them. I use the boiling water trick along with a product called "greased lightning" works better than carb cleaner. glad you got some results. good luck with your carb