Strange Problem

Stubby

Famous Member
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65 Mustang

68 200

DSII dizzy, DSII module with blue strain releif, Pertronix flame thrower coil running on 12 volts, new wires, cap and plugs, all good connections.

Weber 32/36, installed new and jetted about 2500 miles ago, mounted with fuel bowl facing forward. Factory fuel pump and no regulator. :roll:

V8 T5 trans. 2:83 gear.

With everything good and hot, cruising at 65 in fourth gear. Floor it and at 75 to 80 mph it will fall on it's nose like you turned off the key. Ease off the throttle and it will cdruise on, mash the gas, again at 75 mph, Flat on it's nose.

If you start at 65 and accelerate from there gently, it will start running ragged at about the same speed. If you keep playing with it, it will eventualy start acting up at 70 mph.

Slow down, put it in third gear, stand on it, at 80 mph it noses over. That would be more rpms and less strain, but at 10 mph more, it would be about equal strain.

I didn't pay real close attention to possible connection with secondaries. I know that when I stood on it, I was useing the secondary. However, I don't know if I used it while easing up to the problem.
I do know that after setting and waiting for me to arrive, I was able to run it thru the gears hard up to 65 without any problems. That was shifting way above the problematic cruising rpm. I actualy drove it about three miles before I ran it hard enough to cause the problem.

It feels like it is running out of gas. However, I suspect the ignition. Mainly the coil. I have had a small intermitent miss. It is kinda like a slight lean missfire at idle. While trying to find the missfire, I was able to make the Pertronix coil leak a little blue stuff.

OK I admit it, I actualy suspect the fuel system, but I don't like CHROME ignition parts. :lol: So I will atack the chrome first, then I will play with the fuel system.

Any thoughts or similar experiences?

How embarasing :oops: I posted this in the wrong area. :lol:
 
Gary, why don't run a fuel volume check & a fuel pressure check.
Another option is blow 25# of air pressure back through the fuel line, with the fuel cap off & listen. If you hear bubbles great, if you blow the sock off the fuel pickup you will hear a bluh sound. If the fuel system checks ok go to the ignition system, do you have 12 volts at the coil??
Good luck, driveability problems can be a MF to diagnosis. Keep us informed. Bill
 
sounds like the engine is building vacume and pulling the powervalve shut. does those carbs even have powervalves?
 
Any kind of standing wave or pulse reversion occurring with the intake? A manifold vacuum gauge would be interesting to watch at the fluctuation point.
 
Thanks for the input guys. I usualy like to attack these things alone. Try to solve the puzzle.

With the new job I will be on the road. I will be showing this post to the pilot of this Mustang. Then I will supervise and let him discover the power of Fordsix. 8)
 
We have a winner. It was the fuel filter and pump. The filter was stopped up ( Edelbrock inline filter before the pump) This eventualy led to the demise of the pump.

Interesting observation.
The Edelbrock inline filter uses a quadrajet filter with a check valve. Since this filter was mounted before the pump, it was restricting the suction side of the pump, which is bad news for a pump.

The winner gets a well used fuel pump. It works well below 80MPH.
To claim the prize, you must send me three of your credit cards and your social security card, not the numbers, the actual cards. :P For a speedy delivery, include a check book and ID. :lol:
 
If you got that much junk BEFORE the pump, there is probably still a lot left where that came from. Pull the guage sender and replace the intake filter and clean out the tank.
 
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