After running great for a couple weeks, Susan ('76 Cherokee w/360) has decided that starting is out of the question. Haven't sunk to starting fluid yet, though am probably going to have to. I have a motorcraft ignition, would swapping it out for something else be something to do? If so, with what? I have a 4-barrel carb on now and a 2-barrel that I can swap on. Do the 2-barrels seem to work a bit better for starting? Obviously I haven't had the truck very long so I have no idea what (if anything) else is contributing to the problem. Thoughts and ideas are welcomed!
One possiblity is that the fuel pump diaphragm is leaking and allowing the fuel to run back into the tank. How long does it sit?
I went through half a can of starter fluid before finally replacing the mechanical pump. No issues now.
A properly tuned 4 barrel will also yield better fuel economy and slightly better torque and response in low speed driving, naturally if you floor it and all 4 are open wide it will get worse mileage but make more power.
Another item to check (at least what I found on mine shortly after purchasing it) was the rubber sections of fuel line that are on top of the tank coming off the fuel sending/pickup that attach to the metal lines were so dry rotten that they had enough porosity to allow air to suck in with the fuel eventually getting to the point where the fuel pump could no longer siphon up the fuel from the tank. Then a second section of rubber that joins the front/rear metal lines right near the T-Case was also done for. With all the alcohol in the fuel today rubber lines just do not last long. Hit up a race shop for PTFE (Teflon) lines if you want to never change them again, or just get used to swapping them every 2-3 years. The other thing I found on mine was the fuel sock/pickup in the tank was toast. This caused it not to use the last 5 gallons of the tank at all. Literally ended up walking one day even though we had over 1/4 tank on the gauge. I went and got a small 2 gal can filled it up walked back and it primed and fired right up.
Naturally check the pump which is fairly simple you can pull off the fuel feed line and connect a rubber hose from the pump to a small jar/can of fuel and have someone turn it over. If it draws up the fuel quickly and fires up then you know its something downstream to the tank.
When I put the built 401 back in I am going with an electric pump on mine like Pleontks did. I have found that most carbs like to boil off the leftover fuel in the float bowls overnight or after sitting for an hour or 2 when hot. Especially here in Texas when its 110 deg 3-4 months of the year. The electric pump will refill the bowl as soon as you turn the key providing much quicker starts. For a carb application do not go out and buy the biggest most obnoxious electric pump you can find. A low pressure decent volume quiet pump is all you need, I run my setups with a regulator and return line to keep the fuel circulating and cooler.
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Another item to check (at least what I found on mine shortly after purchasing it) was the rubber sections of fuel line that are on top of the tank coming off the fuel sending/pickup that attach to the metal lines were so dry rotten that they had enough porosity to allow air to suck in with the fuel eventually getting to the point where the fuel pump could no longer siphon up the fuel from the tank.
I may be having the same problem with my 1991 Grand Wagoneer. At times it is difficult to get it to start... As if the carb is dry. It sounds that you guys prefer the electric fuel pump. How difficult is it to install and what brand would you guys recommend?
Thanks for the help guys! Just got back home after a couple weeks away and am going to be working on Susan a bit the next few days. The ignition (or what I assume is the ignition) is a blue box bolted to the passenger's side wheel cutout that says "motorcraft" then "regulator" (or "regulation" it is pretty worn) then a number starting 3277. There is an empty metal tab on the driver's side fender wall with a square-ish spot of un-worn paint that I'd guess used to hold some kind of engine item. The fuel lines in the engine bay are a little worn, but not terrible. They are marked as 5/16" does that sound like the correct size? Also there is some funky metal canister with a 't' coming off of it just free-floating and currently resting on top of the valve cover. Is this the fuel filter assembly? I'm guessing it goes somewhere else? I'll put a photo up in a bit. Then it's off to grab some new clamps and fuel hose!
I just replaced my ignition module. Its located on the left, drivers side, it is silver aluminum. Has two pig tails coming off it, one is a four prong and the other a two. Very simple to r and r. My local oriellys was able to test mine.
Backwards fuel filter? Sweet. So the side with 2 ports goes towards the carb?
In related carb news, should both flaps be closed down when the engine is cold? Seems like a silly questions, but the rear flap is closed and attached to some springs and the front flap is open and just kind of hangs there. It is not attached to any springs, however it does have a little linkage that it can attach to but seems to be missing a retaining clip. I re-attached this linkage and put a retaining pin on. Photos coming! Please excuse silly questions, it seems the more I dig into this beast the more interesting things I seem to be finding...
OK, some new fuel line in the engine bay and correctly oriented filter. Ignition module was tested at Oreily's and was fine. Pumping the accelerator does now squirt fuel. Got the other choke plate attached. Of course when all that was done and errands run it's a little late to be making a bunch of racket for the neighbors to enjoy. I just want to make sure that the filter is now oriented properly. The hose from the top of the fuel pump runs to the top port of the filter, same as before, just swapped which end of the filter went to the carb. When I did that, the funky S-curve piece of metal tubing wasn't needed to align the hoses. Will see if this gets Susan started up int he afternoon!
The fuel line from the pump should go into the inlet (single) side, the nipple offset from center (and smaller) is the bypass and should run back into the tank. The output to the carb is correct, swap the other two, the "clocking" of your filter is correct.
The ignition module cannot be reliably tested unless it is under warm, running environment.
The "other" choke plate shouldn't open unless the four barrel is opened up, it has no use until the lower secondary butterfly is opened.
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put a new filter on! If you turn it around now, the crud will be pushed out to the carb! I upgrade mine to an IC12 coil (NAPA's part number for a '77 Dodge coil) with brass contact cap and as long as the choke closes cold, see if you get a full power to the "I" terminal on the solenoid while cranking. If not, the 12VDC pickup contact inside has burned off.