hefftone
I'm Awesome
This is in essence a follow up to a previous post:
http://www.gmt400.com/forum/showthread.php?11542-Loud-whine-brand-new-fuel-pump
In summation: 1990 TBI 350....replaced dead fuel pump with ac Delco EP381 (07+ vortec), ran great then started to fall on face sooner and sooner after start up. At one point the pump was howling, the sounded like an electric drill. Would idle and run with very light throttle, but more than that it just bogged and did nothing, often stalling. Using the ill fitting rental fuel pressure test kits, i figured the fuel pump must have crapped out....got warranty replacement from R0CK-@UT0.
So now....
I just finished buttoning everything up. New Delco EP381 fuel pump is installed with new delco strainer, all on a (spectre fuel sender and fram fuel filter new as of Feb. 2012.) The TBI was cleaned, and the FPR rebuilt with new spring and diaphragm, adjusted to 13 psi. I also spent some time on the harness. There were a couple of wires that had worn off insulation. I cleaned the wires, heated and soldered them, and wrapped with tape. There is still some voltage drop to the pump....engine running Battery voltage is 14.44v and at the fuel pump harness (& chassis ground point) i have 13.44v.
So I take it out, and its running great. Then it starts to act up after i stand on the gas for a few seconds.....it accelarated fine, then conked out when i let off the accelerator. A few seconds later after shifting into neutral it restarted immeditately.
I continued to drive it around, idle and part throttle were fine, but getting into the 50% throttle range was showing signs of power loss....( I mean feels like fuel starvation). I stopped and popped the hood, all connections at map and sensor plugs where good. After a couple minutes i started it up and it drove better.....but the power still drops off with increased throttle.
I'm at the point now of frustration....these fuel systems are so simple....the pump and the regulator.......then there is the ecm stuff, map, tps, 02, knock, espark control.
The fact that only acts up while driving and at heavy throttle makes it hard to troubleshoot.
CLIFF NOTES:
Problem seems to be solved. It was the filthiness of he tank contaminating the gas, and clogging the fuel filter.After removing and rinsing the tank, new gas and fuel filter she's running awesome. Shoulda have replaced the whole tank when I first did the fuel pump. Worst looking gas I've ever seen. If your filter clogs up with rusty dust, ya gotta Yank the tank.
http://www.gmt400.com/forum/showthread.php?11542-Loud-whine-brand-new-fuel-pump
In summation: 1990 TBI 350....replaced dead fuel pump with ac Delco EP381 (07+ vortec), ran great then started to fall on face sooner and sooner after start up. At one point the pump was howling, the sounded like an electric drill. Would idle and run with very light throttle, but more than that it just bogged and did nothing, often stalling. Using the ill fitting rental fuel pressure test kits, i figured the fuel pump must have crapped out....got warranty replacement from R0CK-@UT0.
So now....
I just finished buttoning everything up. New Delco EP381 fuel pump is installed with new delco strainer, all on a (spectre fuel sender and fram fuel filter new as of Feb. 2012.) The TBI was cleaned, and the FPR rebuilt with new spring and diaphragm, adjusted to 13 psi. I also spent some time on the harness. There were a couple of wires that had worn off insulation. I cleaned the wires, heated and soldered them, and wrapped with tape. There is still some voltage drop to the pump....engine running Battery voltage is 14.44v and at the fuel pump harness (& chassis ground point) i have 13.44v.
So I take it out, and its running great. Then it starts to act up after i stand on the gas for a few seconds.....it accelarated fine, then conked out when i let off the accelerator. A few seconds later after shifting into neutral it restarted immeditately.
I continued to drive it around, idle and part throttle were fine, but getting into the 50% throttle range was showing signs of power loss....( I mean feels like fuel starvation). I stopped and popped the hood, all connections at map and sensor plugs where good. After a couple minutes i started it up and it drove better.....but the power still drops off with increased throttle.
I'm at the point now of frustration....these fuel systems are so simple....the pump and the regulator.......then there is the ecm stuff, map, tps, 02, knock, espark control.
The fact that only acts up while driving and at heavy throttle makes it hard to troubleshoot.
CLIFF NOTES:
Problem seems to be solved. It was the filthiness of he tank contaminating the gas, and clogging the fuel filter.After removing and rinsing the tank, new gas and fuel filter she's running awesome. Shoulda have replaced the whole tank when I first did the fuel pump. Worst looking gas I've ever seen. If your filter clogs up with rusty dust, ya gotta Yank the tank.
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