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Old 04-25-2004, 12:17 PM
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Strange power loss

Bear with me while I explain this -

I have recently run in my new 383 and I gave it full throttle today. In first and second gears it pulled like a train all the way to the rev limit - great, but when I got to third, it accelerated for a 2 or 3 seconds - then it was like someone either turned the fuel off or the ignition got cut off. Then after about 2 or three seconds the power came back intermittantly - only when I slowed to almost sensible speeds did it restore entirely ! This is repeatable.

Now, before I built this engine, I had a highly tuned ford 302 in the car and guess what - I had exactly the same problem.

The parts that are common between the two engines are the ignition which is MSD 6AL with MSD Tach Adaptor, MSD Blaster 2 coil and the Carter fuel pump #4070 72gph, 4-6psi. Both engines also ran MSD distributor - albeit different models.

The 383 has DART 215 heads, Mighty Demon 750 (85P & 89S).
Cam is Crane 118581 (240/248 @ 50 & .543/.561 lift) and running about 10.75 comp. Timing is 16 initial - 18 mechanical.

Any one been here before and know what the problem is.

Mark

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Old 04-25-2004, 12:20 PM
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Sounds like fuel to me. Its possible that the spring in the pump is getting weak, (providing its a mechanical block mounted pump) or a ck valve is going bad. Might be time to "T" in a fuel pressure guage and give it a check. <p>
Another Mark.
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Old 04-25-2004, 12:31 PM
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I should have said it's an electric fuel pump
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Old 04-25-2004, 02:05 PM
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Fuel line too small? hose closeing off at full fuel pressure? Tank pick up at front of tank, not picking up when car is pulling hard?
or ignition box breaking up when full load. Or battery has dead cell not putting out full voltage when loaded hard I think most boxes and systems pull about 16 volts at max output.
Hope this helps some.
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Old 04-25-2004, 11:29 PM
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I had that problem in my car,fuel pump couldn't keep up with the carb.
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Old 04-26-2004, 12:12 AM
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yup, you're running out of gas for some reason-

K
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Old 04-26-2004, 01:15 AM
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If this was an automatic, and both engines showed the same symptoms, I would think the clutch pack in third gear was going away. Fuel could also be the problem, but that usually exhibits itself at the end of high gear, the car just stops accelerating..

BTW..where is the electric pump mounted? Since they are pushers, not pullers and work on being gravity fed.

Ron
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Old 04-26-2004, 12:39 PM
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Sounds like a fuel problem to me. Can you mount a fuel pressure gage in a location where you can view it while driving the car? Looks like you'll just have to use process of elimination until you find the problem. I'd start with fuel and then turn to ignition. Good luck!
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Old 04-26-2004, 01:34 PM
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74Ventura, I have 2 1972 Venturas, It is cool to see someone else with one.

Adam
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Old 04-26-2004, 02:00 PM
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Quote:
Originally posted by killerformula
yup, you're running out of gas for some reason-

K
YEP...................................
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