Badart
Senior Member
One thing that I have not changed is the factory ignition box. Do you think that I need an orange box? Could this be the problem?
One thing that I have not changed is the factory ignition box. Do you think that I need an orange box? Could this be the problem?
My motor seems like it is running out of fuel at high rpms sometimes. It can pull hard to 6K in first and second sometimes, but other times it seems like it is running out of fuel. It acts like someone turns off the key at around 5 K for a couple of seconds then it cuts up then runs normal.
Here is some specs on the motor. 318 9.0-1, 904, magnum heads, XE 256 cam, hookers, 3" exhaust, holley 4160 600 cfm, fuel cell with sump, holley red pump.
I have a fuel pressure gauge before the carb and I am getting a constant 5 1/2 psi and flows like a river when disconnected. I am running a high capacity fuel filter before the pump and another filter before the carb. I have checked both filters and they are clean. I am feeding my first filter from the fuel cell with 8an and also 8an to the pump, then I am going to 6an then to the factory fuel line. Is the factory fuel line too small to power my little 318? Should I step up to all 3/8"?
Sounds like you are totally running out of fuel or spark. Not sure if incorrect jetting or anything else mechanical (valves, springs, etc) would make it totally shut down. If it were something like that, I would expect it to miss but not cut out completely.
Could it be something simple, like your fuel system needs to be vented/non-vented, etc? Since you changed the fuel system, you could be doing opposite of what is required.
I have mounted my fuel pump and filter below and behind my cell and about 1' from it. So it is pushing fuel to the pump. The cell is vented fine, because I can fill a gas can pretty quick with just the pump running.
Is your pump by the tank (push) or by the engine (pull)? Should be closest to the tank for maximum fuel delivery.
Can you reproduce the problem by just mashing the throttle when you standing still, or does it need an actual load on it to do it?
I would think the stock 66 jets that come in that holley would be close, I wouldn't think you would need to go down 4 jet sizes, but what elevation are you at?
the ignition box stock or orange is a pos for what you are doing
[over 5800rpm], I mean to say that there are better units out there
[chome box/MSD]and why mess around.
unless you have acceleration/off the line issues, leave the shooter alone.
like T said though you would normally see a 35+ or so nozzle with 3000 stall.
Either way your jets are easy to change as is your ign box. Let us know if it makes a difference. It could be spark scatter or leaning out but it's real hard to tell from here! Change something and get back to us bud!
Does it do it if you leave the car in high gear and run it up light throttle, then nail it to 6K? If you are looking for a budget module, find a Standard Ignition LX-101. It wont pull out timing like the orange box and the quality is more consistant. I've got 3 potential spots.. The carb.. is it new? Crap in it somehere? The ignition box... Is it grounded well? Is teh egnine grounded well? The valve springs... I think you should have enough with the GM 3100 springs but I can't recall what the presures are. Which is why I ask if it will ever rev beyond 6, or just in first. If it never would... I'd pull a spring and test it.
Thanks W&C. I live at 5,500' elevation, so I thought the jetting would be about right. I have heard that for every 2,000' that you go down 1 jet, so 62 seemed pretty close, but they are easy to change and I will play it them.
That's assuming that it's jetted right to begin with at sea level. Don't forget that with all the changes you've made it's sucking way more air up in rpm range. I'm at a mile high and am running 74's all around on a .040 over 360 with a Lunati 60401 cam, 10.2:1 comp ratio and a 650 dp. The stock jets were 68's.
It really only does it when I hold it to the floor for an extended period of time. I still think that it may be getting lean or running out of fuel.
not to side track but we both know that carb is too small if you've up'd the jets 5 sizes.
you are running pv's , explains the 74's across, otherwise 82 secondary.
I don't think his 256* cam'd 318 is gonna pull that 600 very hard.
he may be fine with the jets, but has he done any vacuum checking and have the correct pv installed?
I would keep the jets no more 9 sizes apart, so find out what secondary plate you have to convert the # to jet#'s and see if you are too fat on the secondary side, along with timing...find out when [rpm] the full advance comes in.
just a drunkin ponder.