Hey guys. I have a question about the fuel filters on the 401. I recently purchased a new fuel filter for my '63 Electra. I bought it from the local auto parts store. It was a little difficult to find one that would work since the 401 apparently has a return line, so you have 2 hoses coming out of one side. Anyway, I found one that fit. Now I'm having a little trouble getting fuel. If you let the car idle and then floor it, it misfires. I played around with a few different things, and I think it might be this new fuel filter that's causing the problem. Is there anything I should know about the stock 401 fuel filter that could possibly cause this problem?
The inlet nipple is the single nipple. The outlet nipple and the return nipple are on the same side (opposite the inlet). The outlet nipple is the larger of the two, in the center. The return (vent) nipple is the smaller one on the outer side of the filter. If you do not connect up all of the hoses that way, you will be short on gas in the carb. I can send you a picture, if you'd like. Jim
Did the filter you came up with have the same diameter as the bracket it fits in? Everything I've found lately has been smaller in diameter than the original. Ed
Yeah, it was a little bit smaller than the original fuel filter. I don't think it would matter, though. o No: Yeah, I have it hooked up like that. I know it's not leaking, but I might be able to put the hoses on so they fit the nipple a little tighter.
Is the vent nipple restricted; or are you blowing your fuel pressure back into the gas tank via the vent plumbing?
I don't believe it is restricted. All the plumbing looked good when I put it in. I suppose I could double-check... Does anyone know why they put the return line on the fuel filters? I wouldn't think it would be necessary. Maybe you know something I don't. o No:
It's only on A/C cars from what I understand and it's there to prevent vapor lock from happening when using it. I think adding a clutch cycling switch to the compressor would also prevent it.
There is a small hole down inside the vent return nipple, restricting the flow of liquid fuel out of the filter, you just didn't see it because you did not know to look. It is there. As shurkey says, it keeps pressure up in the fuel filter to keep fuel flowing into the carb. The vent it there to pass any vapor that comes up in the fuel line back to the gas tank. It is only used on A/C cars because the underhood temperatures can get quite high and the fuel literally boils in the fuel lines. I'm not so sure this is vapor lock; maybe it is. Cycling the compressor will make no difference on this. If the A/C is on, it is hot under the hood.
So what can I do to fix it? Oh, and I should let you know that the A/C on this car isn't working. I don't know if that makes a difference.
Did it have this same problem before you put the new filter on? You could have a break in the fuel line from the tank to the pump.
Not really. The problem was drastically greater after I swapped fuel filters. I'm going to see what happens if I put the old one back on now that I've done some other tuning to the engine.
Is there any way that I could check that? I bought a new distributor cap, and points & condenser, but I don't know about the actual distributor. I think the problem lies in this vented nipple I'm hearing about. Because the engine never really ran completely smooth, but when I put that new fuel filter on everything went to crap.
The weights on the '63 distributor are a liitle different than the later ones becuase of the Dynaflow transmission. Kinda hard to tell without looking at them side by side though. Maybe the part no. tag is still intact on your distributor?
distributor part no. is on a strip of tin wraped around the body, quite frequently they're not intact or covered with grime.
I was a part of GM's 100 aniversery parade last Sunday and my car vapor locked Big time. The parade was stop and go for about an 1 1/2.
Ouch. That's really what I'm trying to avoid happening to me. People have been telling me it shouldn't hurt to bypass the return line, but I don't want to vapor lock while I'm driving in traffic.
