So my new truck is doing something really weird. It seems to not want to start after I have just gotten gas. I've never had this happen before just wondering if anyone knows what's causing this.. Thanks. It's a 390 with a C6 and a four barrel if that helps at all..
sounds like water in your gas was it raning alot lately in your area ? did you buy gas when they were getting a truckload full take off fuel line at carb crank over into glass jar or suck it out of tank let it sit for a whyle if there is water it will seperate that is where i would start
Could be junk in the tank, putting fuel in stirs it up. Same idea as the water already suggested. But I would think if either of those were the case it would run rough at least occasionally, and not just at the gas station. It sounds like this has happened more than once? And I'm going to assume that the truck runs fine the rest of the time since you didn't mention it. Is the gas station the only place you shut it down and try to start it again while the engine is still warm? And does letting the truck sit for awhile fix it? Ie, did it eventually start? Just trying to narrow things down, ie, is it filling up the gas tank problem, or a warm start problem.
I think you might have nailed it.. It has only happened to me once but the previous owner told me about it.. He said to floor it when I was trying to start it after fueling up.. Totally makes sense now.. The filter is probably getting bombarded with crap stirred up by refueling.. I'll start there.. Thanks..
Warm start problem is my bet. Shutting down to fill up may stir up tank debris or end up watering the gas, but that's not gonna do anything to the fuel sitting in the carb bowls. I'd expect either of those problems to manifest as crappy running within a couple miles of fueling up, once the pickup tube is blocked abit, or the watered fuel gets pumped up to the carb. More details are needed: how long does it sit before it'll starts-what do you have to do to get it to start-is it repeatable each time (always works?). rick. edit: just read your last.. flooring it clears a flood- the flood that is probably happening when the heat of the mill warms the carb, dumping fuel in the manifold.
When you floor it and then turn it over, it prevents the idle circuit from letting more fuel in and the low vacuume created when turning over the engine wont let fuel in from the secondaries so you are rushing air into your cylinders until the fuel mix in the cylinders can ignite. Once the cylinders ignite, the engine fires and the rpms and vacuume increase and now draw air and fuel. You are most likely leaking fuel past the needle and seat causing this flooding condition.
Pop the fuel line off --take a glass jar --fill half full---let stand--you might see two layers in that glass---#1 Gasoline---#2 CORN SQUEEZ-IN'S
Also if it were running good and you shut it down. You still have clean gas in the bowls and fuel line which would let the truck drive a minute or so before running like crap if you did stir up crap in the tank while filling up. You are flooding!
i should think a flooding condition would happen any time you shut it down warm-ie getting gas, getting grocheries, getting a six pack, getting a piece of tail..... but if it only happens during gassing up? is it a pressureized system?
My exact thoughts too. Even if you had a tank contamination problem it would still start on the gas in the float bowls. It sounds like fuel percolation to me. My last 390 2 bbl. ALWAYS did that on a short heat soak. It would perc all the gas out of the carb and I would always have to floor it and crank for 15-20 seconds to get it started. I tried severel things to cure the problem with the old 2100 Autolite. Pitching it out and going to a Holley cured the problem.
Thanks for the input guys.. This carb from what I can tell is a Weber four barrel if that means anything.. Looking at the fuel lines they seem a bit big to me.. Markings say they're 3/8's..
The tank isn't venting out the fumes/air when you are filling the tank. You need to let out the gaseuos stuff. Now you are compressing it and forcing liquid thu the pump and past the neddle and seat, flooding the engine with extra gas. Filler neck problem not letting the fumes out the neck. How is the tank vented? Just a vented cap? or is there an external vent?
Does the truck have a solinode with 2 small termials. Ford had the 2nd terminal run dirrect to coil. What this does is puts more current to coil and only when starting.When you let off its goes back to running order. So that wire runs from 2nd terminal to pos on coil. I had that problem and worked for me.
It could be the starter getting to warm,exhaust to close. I had the same with a 289 in a 66 Galaxie. Started fine when cold
My F100 always starts right up after I get some tail...(I've had it for years, and it's conditioned to that by now...) Years ago, it knew it had better ignite fast to get out from under the hail of bullets from angry husbands! I love that truck...
It might just be a bad gas cap if it's a vented one. Just try starting it with the cap off next time you fill up. If it starts easy then get a new cap.
YES...Brilliant! Out here in CA and possibly in OR where the OP lives...we have these plastic hoods over the nozzles on the gas pump that seal on the filler neck to catch "vapor" or some eco shit like that...I can totally see that forcing fuel through the pump and the carb, flooding the motor. Incidentally that is a trick I use when I am trying to bring a barn find back to life...I put a little compressed air in the gas tank...not a lot..like 5-10 psi or something but enough to force the fuel forward through the lines...doing that will also show you if any of the rubber lines are bad as it will start leaking there...I am sure that the gas station nozzle has way more pressure than 5-10 psi.....that nugget is why I love this place!
A tank that wasn't venting right would cause the truck to stall out after a few couple of miles of driving. I had that with my 51 Merc years ago and it was a cap that wasn't venting. His problem is that after a quick stop for gas the truck won't start and most likely the problem is the carb perculating or otherwise leaking fuel from the bowls into the intake. Bad needle and seat, bad float or a missing insulator between the carb and intake. Most likely he doesn't make a lot of quick stops where he stops for five minutes and gets back into the truck and goes again. To work, back home and to work again with several hours between start ups except when he stops for gas. I'd say that you need to either rebuild or replace the carb to start and then go from there.
I would suggest fuel percolation too, however, I am not sure it is warm enough for this in most places. I had an issue with this last summer with an Edelbrock carb. I adjusted the floats lower, added a fuel pressure regulator, and it still happened. I had to add a phenolic baseplate to solve the problem. It did not just happen when refueling though. An ignition problem would cause this too. On occasion, my MSD will not fire with my electric fuel pump running. I can tell immediately if my tach needle isn't jumping and just shut off the pump for a few seconds while starting.
To force fuel past the needle and seat, that would take 7 lbs of pressure. Theres no way! Those closed rubber covers over filler nozzel actually suck fumes so thats an open source that wont allow pressure to build. Besides if you created pressure, after you removed the nozzel you'd be doused with a ton of gas. All my tanks are non vented and I have never run into this at the gas station. How many times has this happened? I'll bet all you need is a cheap carb rebuild.
Try filling it up with it running, and see what happens.I know your not supposed to do that...but I'd give it a shot just to see what happens.
I'm leaning towards the carb being the problem as well.. Now that I think about it she is kinda hard to start when she's cold too.. Takes a little bit of playing with the choke and feathering the throttle for awhile.. The carb is brand new so maybe I was a little too cqick to rule that out..
It's a carb issue. There is no pressure being built up while filling becasue you are not adding fluid to a sealed tank, it is open to atmosphere while filling it. If it had alot of junk in the tank, you would have problems more often then you are, and the fuel filter and carb should be full of crap. I had a similar case with an AFB on a 440 in my '37. I had problems with a hot restart. I shut it off and removed the air cleaner and just watch it. It started to dump fuel into the engine due to perculation. A 1/2" thick plastic spacer cured it. Try doing the same senario but without actually putting gas in the tank. Bet it still does it...
I tend to agree with those recomending a phenolic/plastic carb spacer as I've had to do this as well.
Well it's definately not bad/dirty gas.. Cleaned everything out and put a new clear fuel filter in and ran it for awhile.. No junk in there at all.. I guess I'll try putting a carb spacer on next.. I put gas in it today while it was running as well and nothing happened.. ran it for awhile afterwards then shut er down.. waited a couple minutes and it did the same thing.. Had to bury the pedal while turning it over to get it fired up.. Also put a brand new starter solenoid on just for shits and giggles
Hi, Sounds like your dumping fuel into the engine after its warm and you shut it off....Starting is easier if you open the throttle all the way because it clears the fuel out of the cylinders, eliminating the rich condition. If you can, pop the hood, and the air cleaner after its hot and you shut it down. Try to see if fuel is trickling down inside the carb. I've had this happen when Holley's got hot on me with a big block. Solution is to reduce heat to the carb, like suggested with phenolic spacers, or open the throttle every time to start it up after it sits for a bit (not a good solution, but it works to start it when it's giving you grief). Good luck...
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