69roadrunnerragtop
Active Member
Ok i hope you RR guys can help me figure this out. sometimes my fuel pressure drops to 1-2 psi. i been having this problem for 2 years now. it seems to be when my engine temp gets up to 195* or higher. this weekend i drove my car to Carlisle about 270 miles one way. i left at 4:30 am got there around 9:30-10 am. my RR ran 180* the whole way there fuel pressure sat at 9psi and only droped to 8psi for a second or two when i hit the gas this sounds normal to me. but later in the day when it hit 90+ the engine temp went up to 190* and thats when my problem came back. my pressure droped to 5 psi running at 2500 RPMs and in traffic it would go down to 2 psi. the next morning the fuel pressure was great again till the afternoon and it got hot again and the problem came back. i left carlisle early and about 1 pm hit traffic but it wasnt to hot out engine temp hit 185* fuel pressure held ok. today i drove it at about 3 pm and fuel pressure was down low again engine temp 190 outside temp 93. when i drove home at 9pm it was much cooler at night and pressure was great. this is what i did sofar. replaced fuel pump numurous times, all new fuel line 1 pice front to rear. new filter,new tank, new pickup, new tank vent tubes. here is a list of what is in my RR now BTW i have a 440.
what i have in my RR now starting at the front to rear.
1- Summit racing 750CFM, part number SUM-M08750MS mechanical secondary carb
2- Summit Racing SUM-230102 fuel filter
3- 6 -an fittings and braided hose connecting carb to filter to fuel pump
4- Carter street strip fuelpump 120GPH 9psi #GM4862
5- 1/2 inch aluminum fuel line routed as far away from the exhaust in stock location on outer lip of rocker panal and up INTO trunk and droped down right at the tank pickup
6- New 1/2inch pickup tube sender switch.
7- new tank with all new vent tubes. and new gas cap
can anyone explain to me why im having thease problems.
i never had thease problems when i had the old AFB carb, stock fuel pump, old rusty 5/16 fuel line, old broken sender pick up, and old rusty leaking tank, as far as i can remember.
what i have in my RR now starting at the front to rear.
1- Summit racing 750CFM, part number SUM-M08750MS mechanical secondary carb
2- Summit Racing SUM-230102 fuel filter
3- 6 -an fittings and braided hose connecting carb to filter to fuel pump
4- Carter street strip fuelpump 120GPH 9psi #GM4862
5- 1/2 inch aluminum fuel line routed as far away from the exhaust in stock location on outer lip of rocker panal and up INTO trunk and droped down right at the tank pickup
6- New 1/2inch pickup tube sender switch.
7- new tank with all new vent tubes. and new gas cap
can anyone explain to me why im having thease problems.
i never had thease problems when i had the old AFB carb, stock fuel pump, old rusty 5/16 fuel line, old broken sender pick up, and old rusty leaking tank, as far as i can remember.