runs mint to 3800, then falls on it's face
 

Fuel pump????? or what....


changed to the yellow secondary spring and it surges during acceleration and falls on it's face at about 4000, dropped it back to purple spring and it did the same, less the surging.....

------------------
84 GT,shorty headers, open dual's, bored .060, 10.5" clutch, T5, 89 heads, edelbrock Performer manifold, matched cam, 600 Holley..

The secondary spring is not the problem. What kind of fuel pump are you running? You should have 4-7 PSI (minimum) going to the carb. Check that first. Could be a weak fuel pump or a clogged filter or a crimped line. All those would show up as low fuel pressure. Get a vacumm guage at AutoZone or somewhere. Those have a pressure reading as well as vacuum. That fuel pressue reading should tell you something.

Rev

------------------
'66 Coupe, 306, 300 HP, C-4, 13.97 e.t., 100.3 mph
1/4 mi.

stock fuel pump, checked the pressure, 7 psi, manifold vacuum runs 19....

Holley Carb was brand new with the motor, only 300+ miles on it.....

replaced the power valve just to be sure.....

if i were you, i would convert to a fuel injection and trash the carb. Get a 75mm Throttle Body, and invest in a Holley Systemax Air Intake Manifold & Kit. Put on some 24# injectors, and go with a Competition Fuel Pump (this will eliminate weak pressure throughout the fuel lines. Also consider having your tranny checked, if you are surging then falling around 4000 RPMS. If that doesn't work, then get that baby to an ASE Certified Ford Tech ASAP!

on 2nd thought, take that back. My dad has been a mechanic for 20 years, and i asked him what the prob might be, and he said it would most likely be an exhaust restriction. Which means that your engine exhaust is not going where it should. so either your exhaust manifold is cracked and leaking, your heads are bad, or you have a leak in your headers. Something to get checked out.


Andrew

Andrew

no offence to your pop's, but 2 1/4 strait exhaust, nothing from start to finish!!! new headers with the new motor!!!

so, unfortunately, his theory (much like mine) is mute!!

replaced the fuel pump and filter(just to be sure)... no change!!!!!!!!!

It's gotta be something in the carb!! I guess Holley tech's are like ALL others, worthless!!!

Anyone wanna buy a Mustang "it has a new motor"?????????

------------------
84 GT,shorty headers, open dual's, bored .060, 10.5" clutch, T5, 89 heads, edelbrock Performer manifold, matched cam, 600 Holley..

yippee, thx PK, You-da-man!!!!!!!!!!!


can be proud of my mustang again, thus the name change....

------------------
84 GT,shorty headers, open dual's, bored .060, 10.5" clutch, T5, 89 heads, edelbrock Performer manifold, matched cam, 600 Holley..