still having fuel issues

[Supra'85]

ok so ive posted on here before and i need more help. my car was cutting out at about half tank and i figured out that it is fuel related because as soon as i fill up the tank it runs like a top. so i replaced the fuel pump, cleaned the fuel tank out, and replaced the fuel filter and no luck. after i replaced those items i went to get on it one day and it immediatly died i fugured out that it ate the fuse in the engine compartment. i think it was a 15 amp fuse all i had was a 20 amp so i used that to try and get home and it has been in it ever since because it still pops the 15 amp fuses. the other day i was driving and my car sputtered just as i lost all of my park lights and tail lights and i figured out i must have some kind of short somewhere but im wondering if the lights and the fuel pump are related and i have a short in the wiring to my fuel pump. any input or help would be great the car will die very consistantly at half tank and im working on making a fuel pressure gauge like the tech article on tsc performance so until then what should i do?

Thanks
-Justin-

PS: i tried searching a bit but didnt find anything

[Dave A.]

Which 15 amp fuse keeps blowing?

Try loosening the gas cap just enough to where it doesn't seal on the filler when you reach 1/2 tank and see if that temporarily cures the stalling problem.

[Supra'85]

the EFI\ECD fuse in the engine bay

[Dave A.]

The 15 amp EFI fuse supplies power to the fuel pump. What fuel pump are you using? Stock? Walbro?

[Supra'85]

im using a stock replacement its only about 2 months old and even less than that has been spent driving because it sat for a while but the problem never changed even when i had my crazy old dusted pump in there 6 months ago

[Supra'85]

and i thought i would say that when the lights went out it blew the tail light fuse and its a 15 amp also

[jsn_ayers]

I would look at your ground wires from the battery to the frame. I bet the gas grounds the pump when more than 1/2 tank and when it lowwers past the ground clip on the pump it trieds to use other means.(senor ground/tail light ground) Look for a loose or cracked wire by the pump plug.

[Supra'85]

yeah that makes sense because it is so consistent and it happens when the fuel just breaks below the connectors

[Supra'85]

hey what would happen if i made a ground right above the fuel pump off of the power connector? i was thinking about just making a "T" and attaching a new wire to a good spot on the chassis and i want some input before in case im going to screw something up lol


Thanks
-Justin-

[Dave A.]

The wiring diagram shows that ground for the fuel pump is "located in back panel near door key cylinder". I'm not sure where that ground point is. In the hatch, or in the area below the hatch key cylinder? :whatever: I would try and find that ground point first and go from there.

[Supra'85]

k thanks i looked a little for diagrams on ALLDATA but they really suck and i just found my repair manual in the car this morning so ill check it and maybe do some replacing i replaced the ground from the battery to the chassis with a nice new 9 gauge wire so it should be working better

[Dave A.]

That same ground point is used for all of the rear lights as well.

[Supra'85]

hey hey i think we are getting somewhere i am going outside right now to find that ground and inspect it!! it all makes so much sense! thanks you so much dave!

-Justin-

[Supra'85]

ok so i found the ground (it is almost directly under the latch assembly between the taillights) and it looked alright but i took out the bolt and sanded all the paint off and filed the terminal a little so it is metal to metal contact. should i pull the loom apart and check for cracks or tears in the insulation and could the fact that they didn't have a very good ground cause it to blow fuses like that? \


thanks
-Justin-

[Dave A.]

Is everything acting normal now that you've cleaned up the ground?

[Supra'85]

i dunno yet im leaving for school here in a little bit and im going to test it because my tank is right around half and it should want to die. im going to throw a gas can in the back for now and if it dies ill just put more gas in. ill update you if it works or not


thanks
-Justin-

[Supra'85]

hey guys problem solved!! it was a ground issue but it was a little more than just the ground point. so first i found the ground, filed the paint off, and cleaned it and i saw a major improvement. it used to just die....and thats it, right up until i put more gas in. but now with the ground point cleaned and working better it just sputtered and i lost a lot of power. so i made it to school this morning and i followed the ground from the pump all the way to the ground point and you would not believe what i saw, one line came out of the pump and for some reason it split into two. one of the two was grounded and the other one was taped to the first one. just taped there. not doing anything. so i cut the second wire off and properly soldered all of the shitty connections and i am proud to say that i am in between half and quarter tank and she is running like a top! im going to clean and organize the wires better but now for the first time in a year i can go further than half tank! thank you guys for helping me i am very grateful!!


thank you,
-Justin-

[Dave A.]

The thanks should go to Jason for being able to pinpoint the problem. Nice work, Jason! Do all of your rear lights work properly now w/o any fuses blowing? Did you put the 15 amp fuse back in place of the 20 amp fuse?

[Supra'85]

well i put a 15 amp fuse back in the taillights and they work fine but i lost my excitement this morning when i was driving to school. i had been driving around a lot yesterday evening to try and test everything and it worked out. it didnt even sputter a bit. but this morning i was on the freeway and it actually died. it sputtered a bit like it was running out of gas and then died. luckily i had 7 gallons of gas in a can with me. i put that in and it started and ran great. i think im on the right path though so if anyone has more ideas i am open to them. and yes thank you jason you nailed it on the head with the ground wiring. i think im going to tear into the power portion of the pump and see if i have problems there too.


thanks
-Justin-