Fuel pump help please.

[YzGyz]

Hello and thank for looking.

Let me fill you guys in with some background information leading up to now.

BP v2.0 kit, no other furl mods other than what comes in the kit.

Last night on my way to work, my car broke down. I was at a intersection in neutral waiting for a safe break in traffic to tun right and merge into traffic. As I was waiting for a opening in traffic flow, the engine died. I tried to crank it a few times but she would not turn over. It was getting dark so I get towed home.

-I'm off today so I tried to investigate. My first thought was the relay for the booster cable connected to the battery must of went bad. I switched it with the oil sump pump and tried to crank her up, no good. So the relay checked out ok.
-I took out the fuel line from where it connects to the furl rail to see if anything comes out. nothing...
-I pull the fuel pump bucket and all out of the gas tank. I bench test the pump with the car battery and the pump runs no problem.
-Fuel pump fuse checked and it's ok too.

-I plug the fuel pump back up the the power harness and turned the car on. No power to the fuel pump.

This is the power booster cable I'm talking about




It's part of the BP kit. The bigger pump draws too much power and the OEM power wire could not keep up due to being too small in gauge.

I made a small cut on the red and green booster wire to see if I was drawing power in ACC. No power. I tried the multimeter with one prob on the red and one prob on the green, it read no power. I then tried the black prob form teh multimeter to a gournding source and the red prob to each booster cable. I first taped the red booster no power; then the green booster, no power. I'm not sure of what I'm doing but that's what I did.

I'm really don't know electrical so I'm at a lost. I'm thinking that booster cable is busted somehow or whatever signal the ECU sends to the furl pump to turn it on is bad. How do I test or find this out?

YzGyz

[dP3NGU1N]

Fuel pump isn't activated on ACC, it will prime on ON position for a few seconds and then stop. I would check for power during that time.

Any other variables? I'm not familiar with a power booster but if the stock wiring was too small a gauge to run the pump before I don't see how keeping the stock line is going to allow it to run after. Also, check your grounds if you needed to add any for the booster - recently had a whole ordeal where a faulty ground was my culprit.

[TechnicZ]

Ok from what you said:
-You have no power coming from the wires that are supposed to supply power.
-You made sure your multi-meter was on a good ground source to give you an accurate reading.
-Main fuel pump fuse is good.

Questions:
-Is there another fuse supplied by BP kit?

My next steps would be:
-Make sure fuel pump relay is good
-Make sure there's no opens (breaks) in the wiring that was installed there by doing a continuity test from source to fuel pump (make sure to isolate the wiring)
-Make sure the ground wire is good. No ground = not a complete circuit for amperage to travel.

Good luck! Definitely try and contact BP.

[Boosted Performance]

If the pump work on the bench, then there must be an issue with the power supply. It is relatively simple.

Old OEM fuel pump power supply now sends the "ON" signal to the relay, which toggles an internal switch, bringing power straight from the battery to the pump.

I would check your solder connections first.

[TopgunZ]

I had the WORST time figuring this out on my 350z many years ago. It turned out to be a fuse in the main fuse box, by the battery, that was the issue. It was labeled "int" or something close. I think it had to do with the fuel cut off in case of theft. This might not be your issue but i would pull anything you don't know what it is for sure in the main fuse box and take a look if all else fails.

[SouthArk370Z]

Originally Posted by Boosted Performance

If the pump work on the bench, then there must be an issue with the power supply. ...
I would check your solder connections first.

Start at the battery and trace your power lines. I suspect a blown fuse or bad connection.

[YzGyz]

Thanks everyone. I'll be checking the fuse box again then my solder joints. I'll report back later with results win or lose.

YzGyz

[YzGyz]

OMFG!!! WTF!! I'm so MAD and so glad at the same dam time!!

I think I found the culprit! It was a fuse between the battery and the relay leading to the bigger wire that powers the fuel pump! I took the whole darn car apart, pulled the fuel pump and everything because I did not remember that there was a fuse leading to the relay! It was hidden under the plastic by the fuse box. Naturally, I went strait to the car's main fuse box after removing the trim and not look up at the extra fuse inline to the relay.

FUK!!!! all that extra work for nothing!! Well almost.. now to go fix it. I'm going to go see if I can just buy a new relay thing and cut/solder it on since the old one is blown up good.

It started with this.


This is the inline fuse leading to the relay for the furl pump.



The darn thing blew up good! The plastic cover was melted onto the fuse seat. I had to use a knife and flathead to pry the darn thing open. It took me 10 minutes to open the cap.


Off to find a new fuse holder and get my car back together and on the road.

YzGyz

[YzGyz]

Yup, that was it. Ran out to the local parts shop and spent $3.79 for a new fuse holder. Got her home and soldered her in. I had my brother crank the car as I sat in the back with the fuel pump. The pump pumps so I'm good to go. Now to put the darn car back together.


Thanks for all the help everyone. Thanks going your way.
YzGyz

[SouthArk370Z]

You may have an intermittent short. You had a LOT of current going through the fuse/holder to burn it up like that.

[YzGyz]

yeah.. It's weird. I had a solder break near the pump before that's why I pulled the pump. Everything looks good with the bucket and pump. I just cut the wires and re-soldered the ones in the first post picture just to make sure that one is ok.

YzGyz

[TopgunZ]

Oh man. I thought you had checked that for sure when you said you traced the wiring back through and looked at fuses. Dang.

However, there is an underlying problem here. Fuses shouldn't just explode like that. Id take that whole line out and inspect it for a cut/rub through somewhere.

[ChaseZ]

This reminds me I still need to pull these lines to the pump. Left it open to test and make sure all worked beforeswapping in the new wiring and relay. Today's project!

[TechnicZ]

Originally Posted by TechnicZ

Ok from what you said:
-You have no power coming from the wires that are supposed to supply power.
-You made sure your multi-meter was on a good ground source to give you an accurate reading.
-Main fuel pump fuse is good.

Questions:
-Is there another fuse supplied by BP kit?

My next steps would be:
-Make sure fuel pump relay is good
-Make sure there's no opens (breaks) in the wiring that was installed there by doing a continuity test from source to fuel pump (make sure to isolate the wiring)
-Make sure the ground wire is good. No ground = not a complete circuit for amperage to travel.

Good luck! Definitely try and contact BP.

I asked this right!?

lol, Glad you found it. Now find a short to ground which increased the amount of amperage past what the fuse can handle.

Check that power wire through and through to any rough edges in your cars body.

Good Luck!