Fuel pump help.

[Todd Black 88]

You should have 12v there. If you have 9v that will overload the pump motor and kill it. Check voltage at your fuel pump relay, coming in, and going out with the ignition on. If its 12v coming into the relay and 9 coming out, replace the relay. Or just replace the relay with a known good spare, and see if its 12v then. If its a motronic car just pull the relay for your horn and swap it in, its the same

[E30SPDFRK]

I am getting 12v to the pusher pump though.

[E30SPDFRK]

I pulled the wires off the pump today and checked the volts and I got 12. When I reattached them I got 9 again, so I think the dmm starts to read something else when I attach the wires. Does that sound like a possibility?

[E30SPDFRK]

Ok, I still haven't gotten this problem figured out yet.

I am getting 12v to both pumps, both are working, but I am only getting 5-7oz out the return line in 30 seconds. When jumping the relay to check flow, they seem to have no pumping resistance until about the 27 second mark where they slow down. I have replaced both pumps with known pumps from working cars and there is no change.

My fuel filter only has about 1000 miles on it, but I am going to change it again. I guess something could have gathered there while I was doing the swap.

Any other suggestions?

[E30SPDFRK]

I checked the lines for kinks that might of happened during the swap, but found none.

[DCColegrove]

I haven't read through the whole thread...But...

As always check your electrical grounds

Did you put a strainer sock on the transfer pump?

Is there Mung in the fuel tank?

[E30SPDFRK]

Cliffnotes so far:
-Started blowing in tank pumps after the car sat for a year while getting an engine swap.
-changed the exterior pump thinking it might be pumping too slow. No difference.
-only getting 5-7 oz out of the return in 30 seconds while jumping the relay.
-blown about 5 transfers and replaced 3 exterior pumps and running out of $ fast.


All my grounds looked pretty good, I didn't see any corrosion. All the pumps have had the socks on them. Nothing bad in the tank.

The only things I can think of would be some kind of blockage on the top of the tank or a clogged fuel filter. I'm leaning more towards something between the two pumps as the transfer is the only one blowing and changing the exterior pump made no difference.

[DCColegrove]

Well...

Shit...

I guess you'll have to tear it all apart and look.

Triple check the tank it's self... Drain and flush...