Starts, but dies when revved, now...

[Captainhaak]

after searching the forums i was unable to find anything that would help:

Here is my current situation:

Vehicle: 72 240z stock l24 w e88 head, 3 screw roundtops stock 4 speed manual, only modification would be a fuel pump mounted at rear of car.

Had the vehicle out one day, driving well, all was good. i hit a bump and the wire i have running next to the driveshaft for the fuel pump got caught on the driveshaft and tore, needless to say the car died. 

flash forward, fixed the wire, secured it better this time and all seemed good, fired her up, and she was once again idling. i hop in to drive after she was warmed up, blip the throttle and immediatly lose power, the car dies

wait a couple minutes, start her up, same thing, idles, rev it up, and it dies. 

 

a week passes, and now she will barely start. battery fully charged. 

 

im assuming it is electrical, maybe i blew something when the positive wire for the fuel pump got tangled in the dri eshaft, but dont know where to look. 

 

any help would be much appreciated 

[Zed Head]

How long are you letting it idle?  Not clear if it's idling for ten minutes or ten seconds.

Could be that the new fuel pump doesn't actually have power and the engine is just starting on residual fuel.

[SteveJ]

You tell us. Where did you break into the wiring for the fuel pump? 

[siteunseen]

Possibly sucking debri from the fuel tank. After sitting it settles back to the bottom then when running sucks back up clogging the lines. It happened to me. Ran the fuel hose into a clean gas jug and it ran fine. Dropped the tank cleaned it with acid and lined it with red-kote. Zero problems in 5 years. 280 & 240 both.

[Captainhaak]

i let it idle for 10 to 15mn to warm it up. fuel pump is good and is working normally, tested by pumping gas tank into gas can via fuel pump, gas tank was recently cleaned,  filters recently changed. the wire was broken near the differential and driveshaft meet. 

[SteveJ]

2 minutes ago, Captainhaak said:

i let it idle for 10 to 15mn to warm it up. fuel pump is good and is working normally, tested by pumping gas tank into gas can via fuel pump, gas tank was recently cleaned,  filters recently changed. the wire was broken near the differential and driveshaft meet. 

Allow me to rephrase. You added a wire. Where did you tap into the stock wiring harness?

[kayinsunz]

air, fuel, spark to start. since you knocked your pump wire out it's safe to assume that its fuel. when you give it throttle, do the carbs cough? or do they wizz fuel? or niether?