Help with fuel pump issues

[lapaipaxxx]

I have a 86 c10 with LY6/4L80e. Returnless style. Recently truck would shut off while driving, but would start right back up again. Have had that issue for like a month. One day it just would not start, so i figured it was a bad fuel pump due to fuel starvation since tank does not have baffles and decided to replace it. Went ahead and ordered new ac delco ep381, 87 baffled fuel tank and installed them.

After installation truck turned couple of times before starting. Took it for a 10 min drive truck ran fine didnt seem to have any issues then came back home shut off truck and tried to restart. Truck did not start. Pump will not prime, so i replaced relays and checked ground but nothing. I dont know what else to check for.

I would appreciate any help with this issue
Thanks,
Jesse

[68GMCCustom]

you don't mention anything about your fuel filter?

[lapaipaxxx]

I have a fuel filter/reg 33737 wix. I have not changed that yet. Do you think that has something to do with fuel pump not prime.
Thanks
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[68GMCCustom]

if your old tank had something in it...and the lines then yes...it could have gotten clogged (not saying it did tho). No prime...where's the pump?

[BR3W CITY]

x2, wheres the pump located?

What your describing sounds like you have too much height or length before the pump and the pump can't draw hard enough so you cavitate and starve.

[lapaipaxxx]

Pump in tank with an 87 sending unit
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Filter is right about 1 1/2 foot from tank
Could a clogged filter burn out the pump?

[ls1nova71]

Originally Posted by lapaipaxxx

Pump in tank with an 87 sending unit
Posted via Mobile Device
Filter is right about 1 1/2 foot from tank
Could a clogged filter burn out the pump?

A clogged filter will definitley put a strain on a pump, and probably could cause it to fail over time, but I don't think it would do it that fast. Have you verified that you actually have power going to the pump at the sender? Checked grounds, especially where thwe tank/pump is grounded. Also I have seen the hose between the pump and sender blow off or get a hole in it and the pump will be running but not build pressure.

[lapaipaxxx]

Thanks for that info, but how do I check to see if the pump has power.
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[awhite4557]

I would start by testing at the relay for power. Connect a test light to the pump side of the relay and have someone turn the key to "on". The relay should have power for a few seconds before it turns back off. If you have power there, then connect the test light to the terminal/ wire at the pump and check it again. The test light should come on for a few seconds and then cycle off. You should also be able to hear the pump run for a few seconds when you turn the key to "on" as well. If you have power and the pump runs, disconnect the fuel line after the filter, unhook the wire to the pump and connect an external 12 volt source to the pump and check your fuel flow. Use a short hose and run the fuel into a clean container for re-use and let it run for a while to see if the pump stops or flow is low. You may also want to check the wire size going to the pump and check for amp drop. That will cause the pump not to work as well. If all works well, connect a fuel test gauge to the fuel rail to make sure you have adequate pressure at the rail.
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[Wasted Income]

I've had to replace at least 2 of those WIX "filter/regulators" that were f'n junk right out of the box.

My bet is on the filter/regulator.

What's the fuel pressure while running?

[lapaipaxxx]

well i think i have found the problem. fuel pump works but no power at wiring harness after rechecking wires and relays found this. Pretty sure its the problem i just need to replace harness. anybody know where to buy both fuel pump and sender harness.

[68GMCCustom]

a ground issue cause that?