Mechanical advice pls- Low Fuel Pressure

[Keith B.]

Experts: I have a 66 L-36, 40,000 org miles. Engine sits in the car as it left the factory. I have my baby into my trusted mechanic repairing my Holley Carb. Further check indicates that I have 1 LB of fuel pressure going into my carb. Bought new, correct # fuel pump and put on car. Same reading. My mechanic is perplexed with far more engines showing too much fuel pressure rather than 1 LB on two different pumps. Lines checked from the tank, steady nice stream of fuel coming out of line however once into mechanical pump, same 1 LB pressure that I'm told should be 4-5 LBS. Mechanic feels it is likely my CAM, fuel lobe is gone, however his experienced ear tells him the rest of the CAM sounds fine but why the low fuel pressure. In the interim I'm looking at putting on a electrical fuel pump........to buy me some time and $$$$.

Question: In your experience does it sound like the right diagnosis or are we missing something, is there a way to test to see if the CAM fuel lobe is gone w/out pulling everything apart?? ANy other thoughts as to why LOW FUEL PRESSURE??

Much appreciated......

[Rob Dame]

Re: Mechanical advice pls- Low Fuel Pressure

I'd go your local auto parts store and buy another fuel pump and give it a try first. Rob

[Mark S. Lovejoy]

Re: Mechanical advice pls- Low Fuel Pressure

You can measure the cam lift fairly easily, do that before taking the engine apart.

[Brian Monticello]

Re: Mechanical advice pls- Low Fuel Pressure

Be sure your mechanic checked the pressure before the filter.
Brian

[Clem Z.]

Re: Mechanical advice pls- Low Fuel Pressure

the pushrod should move about 3/8" in and out.

[Jack W.]

Did you rule out the fuel cap? *NM*

[Christopher R.]

Re: Mechanical advice pls- Low Fuel Pressure

Clem, 3/8" in and another 3/8" out for a total of 3/4"? Or, 3/8" total.

[Clem Z.]

Re: Mechanical advice pls- Low Fuel Pressure

the rods move about 3/8" from all the way in to all the way out. i have never seen a fuel pump cam lobe wear out even using very high pressure fuel pumps. pull the rod out and check the end for roughtness. i have seen the rods bent by improper installation of the fuel pump causing them the bind up in the block and not move the full distance. pull out the rod and roll it on something flat and smooth to check for bends.

[Verle R.]

Re: Mechanical advice pls- Low Fuel Pressure

It is possible to bend the pump rod by tightening a bolt too much when trying to hold the rod up when installing the fuel pump. I agree with previous post, check the rod.

Check to make sure the rod is straight and make sure the bolt in the upper right front hole is not too long.

Verle

[Clem Z.]

i was informed it was a bent pushrod

alway check them when changing pumps.

[Mike McKown]

Re: i was informed it was a bent pushrod

That's how they get bent. Changing the pump.