2:40 later and still no pump. More of a data point than an update.
CK5
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Black Betty - Formerly Blaze the Monster Machine
- Thread starter centexk5
- Start date
1984 K5 Project for Dad and kids
6:30 later and no pump.
pump jumped direct to 12v at sender and nothing ?
8:25 and still no pump.
Not direct at sender but bypassed relay and jumped straight to 12v yes.
16:30 later and no pump.
17:30 later and still no pump even when jumpered.
Is there 12V there?
fix it while it's still broken, don't wait for it to work again.
fix it while it's still broken, don't wait for it to work again.
Make a quick test light using a high beam headlight and plug it into your power and ground as close to the pump as possible and then jumper that relay. It will load test the circuit and tell you if it can handle the load of the pump. That way you know if the problem is before that point or in the pump/sender.
Yes there is.
This is at the pin on the connector.
This is at the connection going to the sending unit. One home run.
Can’t do much more as I’m checking stuff in between meetings.
This is at the pin on the connector.
This is at the connection going to the sending unit. One home run.
Can’t do much more as I’m checking stuff in between meetings.
I can try that but I’d be surprised if it couldn’t. It’s a 40a relay and 12ga wire all the way back. The only thing that hasn’t been replaced recently is the sending unit. Brand new Walbro and relay. I’ve verified the Holley is triggering the relay appropriately.
That was just the next logical step always when troubleshooting electrical after checking voltage. You would load test to verify that the voltage wasn't disappearing as soon as the load was added in. Seen it many times where a meter would show good voltage then it would go away with a load due to a tiny connection in the circuit somewhere that could handle open circuit volts but not a load. I'm betting your problem is in the sender.
That's a long the lines of my thinking. I've been thinking that for some reason there is something in the connection at the sender that somehow trips/breaks/whatever after I shut off the truck and it somehow resets itself after a period of time. It can handle the initial load but once that load is removed, it has to reset itself before it works.
It's the same sending unit I had with the previous pump and relay. It ran great for a couple hundred miles but then I had the fuel hose burst in the tank and ever since then I've had this problem. Maybe it was fine when new but after time that connection has just worn out from the load and is slowly failing.
So you're using the same sending unit from the previous pump, and you're still wondering if it is what is failing.
I think you have your answer there.
Assuming this is the TBI sender with a different pump in it for the LS.
Been a few days since I checked. I checked Thursday and it wasn’t running even when jumpering to the battery. Just checked today and it’s up and running again. I’ve got a new sending unit sitting in the garage I’m gonna swap this weekend. Gonna tear the old one apart and see if I can figure out what in the world is going on.
When I installed my current pump (Bosch) I had similar trouble with having power but no pump action, my problem ended up being a harness jumper (that was supplied with the pump) had loose connectors in the plug so you could wiggle the wires and get it to work / not work.
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Looks like the bulkhead fitting is coming off. That red wire is nearly out. Pretty confident here’s my issue.
Plus note, it fired up long enough for me to drive it around to the driveway so I’m not working in dirt.
I think you found the culprit
Yup. Replaced it and the pump kicked and the fuel level gauge works for the first time. But the return fitting is leaking at the connection at the -6 adapter. I didn’t like the way it threaded on. Didn’t feel like it went far enough to seal. Confirmed that thought. Always something.
More I think about it, the more I think it’s the flare and not the fitting. The fitting threaded fine but it never squished against the o-ring like the other one did. It just stopped dead.
