fuel pressure droping ???

Hey guys !!!!! Need some help with my fuel issue .... I got a 440 with a mechanical hv pump and when I first start my car the fuel pressure goes to 6 psi and stays there....once the motor gets hot I start losing fuel pressure ..it will go from 6 to 2 psi and the car will idle but if u go to accelerate it wants to die ! This pump worked on my other engine great so I Know that's ok ....what should I try next ? Anyone have this kind of problem ?? Thanks !!

Not much help here but I will day good luck!

I had a Carter HV pump on my car and could not get it to work. Tried 2 of them. Same problem as you and I did a bunch of troubleshooting and hit a dead end - and I don't give up easily. Ended up going electric.

I even insulated all the fuel lines in the engine compartment and it did not help.

plumb a can of gas in the eng compartment to the pump inlet & retry it. this will eliminate everything rearward from the pump as the culprit (2 short neoprene hoses/long hard line/pickup sock/tank venting). I've heard of the Carter Curse (referring to their mech fuel pumps) but you did say the pump worked fine before (but was it sitting on the shelf along time?)

It's a Holley pump and it Sat for about 3 yrs ....I will try the can of gas n see what happens ! Thanks

B4 I do that tomorr .....any other suggestions ??

got another pump you can toss in for a quick test (even a stock airtex)

I would check the line and where it is routing next to before the pump.

recent exhaust change?

I ran my fuel lines and stuff first then had exhaust put in.
had an electric pump along the frame rail infront of the wheel well.

genius exhaust guy routed the new exhaust as close as possible without touching.

could be something similar since it only happens when hot. could also be after the pump if the line is too close to the exhaust or block.

Check this out.


https://board.moparts.org/ubbthreads/ubbt...tml#Post2065508

Had the same issue on my hauling truck i came to the conclusion that the diaphragm in the pump had a rip in it while it was pumping cool gas the rubber was stiff enough to prevent too much back flow bur as fuel got more warm from being circulated the rubber got softer and just couldnt make enough pressure also had similar issue with the mud truck but that was too much dirt in the tank clogging the sock hope this helps