Most Lean Burn (or whatever the name is on the computer) problems is not because of the computer system.
9 out of 10 times, it is a “non-computer” problem or a problem that is making a computer sensor not work correctly (like an unplugged oxygen sensor, etc.). The 9 out of 10 figure might be too low – it might be closer to 29 out of 30 issues that are non-computer related vs. 1 out of 30 that is computer related.
Unrelated, I have never been a fan of any Holley carburetor (1-bbl, 2280/6280, any 4-bbl version and especially the 2245 (2-bbl used on 360’s and 400 engines)). I have worked on way too many of them and to the point if I have one, it will get replaced with something else – if a finger ever gets pointed to it.
I prefer working on and have had a whole lot less problems with Carter’s – not saying they don’t have their issues – but in general, I have had a lot better luck working on them.
About 10 years ago, the float sunk in my ’86 Fifth Ave – to the original 6280 Holley. At the time, I found a repop Carter BBD (it is a cheap Chinese knockoff – but brand new, and has been working good for me so far) on eBay. Not sure if they are still for sale (hadn't looked). At the time, several versions were being sold, so I picked a ’77 318 automatic without Lean Burn (no computer). It is ironic that about 7 years later I purchased a ’77 318 automatic, without Lean Burn (my station wagon), but back to the story. I think the ’77 might be best calibrated carburetor out there (ie: will fit most all 318’s without much fuss).
The Carter BBD has a different choke rod height to that of a Holley 2280/6280. Also, the fuel line is routed a tad different (fuel lines should work for either carburetor – but you might have to make a slight bend to do so. Also, the vacuum hose connections are at slightly different locations – so if you have your existing vacuum diagram and one from the car the replacement is coming from – you are fine (with a little detective work).
I changed the 6280 with a new BBD, changed choke thermostat and changed vacuum hoses accordingly. The plug-in to carburetor was left undone (nothing to plug it into) and car ran just the same as it did before my float sunk. The original 6280 is sitting on a shelf in my garage (and until now, forgotten about).
In your case, if you do not want to get rid of the computer controlled carburetor, you can fix existing carburetor (if that is what your problem is), replace with a Holley 2280 (should fit without any issue) or upgrade to a Carter BBD (non-computer controlled). Your computer will keep up with ignition timing and will be attempting to control the carburetor (but computer won't know if carburetor is working, or not).
Now back to your problem – it sounds like a fuel delivery problem (weak fuel pump or air leak in fuel lines (metal or rubber) – to me.
Let me ask this, it sounds like your existing 6280 was rebuilt. Did it work the same before rebuild as it did after the rebuild?
If so, I suspect you are close but pointed slightly off direction.
Two things I would do. Being your car is thirty years old - I would bet the rubber fuel lines are, well, way past prime. If hoses show any cracking – they can suck air (which is a lot easier to do than sucking gasoline) and not be leaking fuel externally. Also, hoses can disintegrate internally, in effect can restrict or stop fuel flow because of the deterioration.
I would go get about three feet each of 5/16”, ¼” and 3/16” fuel non-fuel injection hose. You can use fuel injection hose – but it costs about 3 times more. The fuel pressure on a 318 will not see more than 7 PSI (more likely closer to 4 PSI).
Then get under car (well supported – we want you to still be with us for a long long time) and replace those hoses.
There is 3 hoses at fuel tank, 3 hoses at the hidden junction where R/F tire/wheelwell and firewall meet (not hidden, per se – just not a location people look for, for fuel hoses) and a hoses by fuel pump and another at charcoal canister.
The fuel filter has 3 hoses to it. Most (not all, but most) fuel filters come with replacement hoses. Always change those hoses when a filter is replaced. One of those 3 hoses is the fuel return.
I recommend changing the fuel tank hoses first. I also recommend taking the (still un-cut) 3-foot length of 5/16 fuel hose and place on the fuel tank fitting. Then blow through that hose to check for restriction. There will be some restriction – but not a lot. If there is a lot of restriction blowing through it, then you either have a stopped up (in-tank) filter or tank has no vent action. If hard to blow through, first loosen (or remove) gas cap. If still hard to blow through, then time to change the in-tank filter. If a lot easier now – then need to check the 3/16” fuel line/hoses to charcoal canister for restriction, for damage and/or for rust. Also take off the hose off the charcoal canister (with your un-cut 3-foot-long hose) and try to blow through it. If a lot easier – then you definitely have a 3/16” line/hose problem.
There is a replaceable air filter on bottom of charcoal canister that sometimes get stopped up (not often) or a problem in canister itself (again, not common).
During or after hose replacement, visually check every inch of the metal fuel line from fuel tank all the way to engine, for crimps, physical damage and for rust. If you think you have a rusty area, take a small screwdriver, an ice pick or something similar, to prod on the lines. If a rusty area – your prodding will find it.
The in-tank filters look like this
from this website
http://billrolikenterprises.com/search.asp?nobox=&scat=23&stext=filter&stype=&sprice=&pg=3 . There are other locations to find one, as well. The Dodge part number is 1670694.
They pull off/push on – but generally, they come off in pieces. Generally, if the fuel sender is out of car, it is wise to replace this filter while there.
This is a (poor) picture of a typical charcoal canister air filter
I went to look of the number for a replacement filter for your car – and come to find out the filter is not available - it requires a canister replacement (which is part # 4241839 (stamped 4227010)) - or some other modification.
I hope this helps.
BudW
