Is a slight sputter normal?
- Thread starter Fang
- Start date
Mine does the same, ive always wondered how "normal" it is though.
There is a thread here where the car will actually die when you take off from a stop light after idling for a while. Mine does that occasionally. It's from heat soak of the fuel in the rail...it actually tries to boil the gas. It's an issue with the returnless system. I simply raise my rpm for a bit before I leave, then drive away normally. That does it. It will actually miss and sputter for a second at times. That's because the fuel isn't solid at the injectors yet. Once cooler fuel hits the rails, it's just fine. I don't know of anyway around this with a returnless system and just consider it normal. But if it's doing it when the engine and outside air are both cold, you may have another issue. If you have a f/p guage, watch and see what it's doing when that happens.
FireRed04Vert said:
Can't be the only reason......heat? (questioning, not stating with any certainty)
Mine does it when cruising too, like when you are just doing about 2k rpms and you just need to accelerate a little, it will stumble slightly on tip-in.
My rails are like twice the volume of the stock ones so your heat theory would have me heating twice as much fuel to boiling. :shrug:
And that fuel is coming from a -8 line too.
I am going through this right now too. Last night my tuner moved my "closed loop switchover rpm" down and threw a bunch of fuel in at lower rpms and it reduced the stumble by about 50%. Theory is my cams are causing it, some vaccuum reading is off because of that, compensate as described, symptoms decrease.
Car works perfectly on the dyno, try power shifting or just shifting quick and it bogs too. Going to get an "on-the-road" wideband tune by Alternative, hope that does it.
I just cleaned my steeda filter and my mass air meter. Car seems to run alot better. Give that a shot, it is cheap and easy to do. My miss is gone as well.
My last cobra would do a little stutter at low RPMs. I'd clean the MAF and it would go away
postban said:
Doesn't sound like the same problem to me Post. Yours sounds more like a tune problem with the mods you have. This particular problem is only after idling. Yesterday I had the same thing happen again. It was in the high 90's here. I just missed the light and had to sit through the whole sequence. Then, just as it's about to go green, here comes an ambulance and screws up the light sequence. Had to sit through it all again. If I would have just taken off, it would have fallen on it's face and died. I rev it up to about 1500 rpm or so for just a couple of seconds and let it return to idle and leave. Usually that takes care of it. This time however, I had been there so long that even though the car left ok, it still sputtered for a couple of seconds. By the time I got across the intersection, the cool fuel hit and everything was normal. You can actually feel it. There is no doubt whatsoever that it's hot fuel. Ford actually used to have a system on some of their vehicles called Hot Fuel Handling that addressed this issue. It was on the last of the carburated vehicles. It consisted of the use of electric pumps and a bypass/return line.
The fact that you are using larger fuel rails would actually help this particular situation. It's harder to boil a larger volume than a smaller one.
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