fuel pump question (dual feed setup) and bad revving problem

[crazysupra2JZ]

Ok, so a couple weeks ago i ran into a little electrical problem. My fuel pump wires and relay burnt up on me and the wires melted and shorted out. Left me stranded on the side of the road. Well, today i go out there to rewire them using 10awg primary wire to a relay that is rated for a little better performance. I find out that one fuel pump is dead or is still shorted out. I'm running the new wire right from the top of the fuel pump hanger. I made a little hole in the trunk to access the wires. I get a spark when i touch the POS wire to the battery, it's just not pumping... the other one works fine.

i have 2 fuel pumps and 2 fuel lines going to my dual feed fuel rail. is it ok to drive it with only one fuel pump on? will the other fuel pump hold the pressure and basically act as a closed valve?


i started the engine, idles great, fuel pressure is holding a steady 35psi... when i rev the motor the pressure rises and doesn't fall.

i don't have the time or the money to take a look and possibly buy another fuel pump.



oh, and what does N.C and N.O mean on the wiring diagrams for relays.

COIL1= to positive battery terminal
COIL2= to ground
COMM= power input from battery
N.C= resting state for relay
N.O= accessory


the relay that failed on me said
>87a N.C 20 amps
>87 N.O 50 amps

does it mean NON CONTINUOUS. i don't know what the N.O means

the new one i bought was $13 more to purchase. so it must be rated for more current. it says continuous out 25 amps.

i know i could just wire it up to the battery, but i don't want this thick wire inside the car adding so many feet to get to the fuel pumps, i wanted the shortest path possible for it.


and also, my timing is 0 degrees for cams and 3-4 BTDC on the crank, should i zero it all out or will it be fine how it is? i'm also gonna rerun new wires from the coils to the igniter, they are all cracked and wire is exposed and looks corroded.



this is what happened to me before, i used 16 awg wire for each pump connected to one terminal on the relay.

 

[red91turbo]

N.C stands for Normally Closed and N.O. stands for Normally Open. Which means that when they have no power they will revert to this position.

Rich

 

[crazysupra2JZ]

N.C stands for Normally Closed and N.O. stands for Normally Open. Which means that when they have no power they will revert to this position.

Rich

that's good to know, thanks

i redid the wires for the coils but haven't noticed any improvement. still breaking up pretty good.

 

[crazysupra2JZ]

ok, i did a compression test and checked all the plugs.

all of the sparkplugs were gapped between .024 -.030
they are now at .035

1> 155
2> 160
3> 165
4> 160
5> 165
6> 155

it idles a little different, but idles too low, any way i can change this? timing is still at 3-4 degrees BTDC for the crank with the cams at TDC

i think i may have too small of a filter for the IAC valve, i'm using a breather filter for a valve cover for a V8. maybe i need a bigger filter so it can breath a little eaier at idle. if i revv it too much and back off it either dies or about to dies but catches itself and evens out again, itle is about 600-800 rpms. i know that may sound perfect, but it is having a hard time idle that low, again might be cause too small of a filter.

 

[tlo86]

hrm i routed my iac to the intake pipe. was that compression test done warmed up? do you have a voltmeter? i know my car sounds rough when it idles that low but maybe you hooked up your alt wire wrong and thats the cause for it sounding rough (my volts would dip below 12v and it started running bad, went away once i made the wire better)

 

[crazysupra2JZ]

engine was warm when i did it. my voltage is good, the AFC shows 13-14 volts, battery light isn't on. i'm gonna redo my wastegate and stop it from leaking


it's weird, once i start to build any boost at all it bogs down. it won't do anything. i'm watching my fuel pressure and AFR, it's not perfect, but the levels aren't dangerous at all.

 

[tlo86]

how does your map sensor look? hows the vac line to it?

 

[crazysupra2JZ]

how does your map sensor look? hows the vac line to it?

the vacuum is hooked up like stock, i just thought though, the line that normally goes to the stck FPR is feeding into a nipple on the side of the intake manifold

so it's got the one that comes from the filter and goes to the MAP sensor then the other end of the T fitting goes to another vacuun source. you don't think that could mess it up a little?, maybe i should hook it up like factory. i know if the MAP is disconnected it will not run, so it must work.


besides the poor revving, breaking up... when i try to build boost it bogs down, the turbo spools up, it gets to a little more than 5 psi. but i don't feel that power, it actually slows down. i'm gonna take a look at my BCC.

oh, and i don't know if it matters, but i didn't get a wire diagram for the injectors, how to wire them up, does it matter? it's just a solenoid.. and i wired up the fuel injector resistor with black wire, first two, yellow wire, next two, red wire last two. do they need to be redone in firing sequence? like the 7MGTE is. i think that's how i did it last time, it ran fine like that, this time, not so good.

 

[Van Diesel]

I have never done dual pumps on a supra, but on my FD3S (RX-7) I ran dual pumps. I had to run a larger fuel pump relay and thicker gauge wire to the fuel pumps or else it would cause the wires to overheat and melt the rubber insulation. I HIGHLY doubt that dual pumps are only rated to 25 amps. I strongly encourage you to run a much higher amp relay...unless you're running 25 amps PER fuel pump. I'm speaking from personal experience.

 

[tlo86]

besides the poor revving, breaking up... when i try to build boost it bogs down, the turbo spools up, it gets to a little more than 5 psi. but i don't feel that power, it actually slows down. i'm gonna take a look at my BCC.

might be timing or your huge fuel injectors running rich

 

[crazysupra2JZ]

might be timing or your huge fuel injectors running rich

i don't think i have any stock injectors, but i'm gonna take a look in my storage unit and maybe try using them. i don't have the injector clips anymore though. you think the 7MGTE injectors would fit the HKS rail?

 

[tlo86]

give me about 3 weeks i'll send you mine to try ;p, otherwise im not sure

 

[crazysupra2JZ]

i did something today, still getting very rich when i try to build boost. it bogs down so bad.

but revving is a little more responsive, it idles higher, about 1000 rpms. but when i was driving around, it kept creeping up to 1600.

i found a vacuum nipple that was open, i thought it was a water nipple. i routed some vacuum lines a little differently. it drives better, until i try to demand any power from it.
and now it's not running so rich idleing. it's around 13.5 now vs 10.5-11.5

i found this thread, bu i never got an answer to it. i'm gonna check the wire he's talking about and make sure it's getting the proper voltage.

i don't know what happened, but i'm makin progress.

http://www.youtube.com/watch?v=1d_CvpiGH8g&fmt=18

 

[crazysupra2JZ]

here's a picture of what i am suppossed to get.

with ignition ON, car off. i don't get anything on the IDL1 wire. moving the throttle body doesn't change it. i tapped into it while it was running and still nothing. i applied 12 volts to it, it made the engine do smoething for a split second but still idles the same, i haven't tried driving it yet with 12 volts applied.

revving seems to be pretty smooth now, but slow. something is causing it to lag a little bit.

 

[tlo86]

Lol, what line was it?

 

[crazysupra2JZ]

Lol, what line was it?

it was pin 64 on the ECU. green wire. then i went in and teted between IDL1 and E2 and all i got was .03v

are you suppossed to have power to the BO wires going to the injectors and the coils with ignition off?

for some reason, i have 8.8 volts when i connect to the ends going to the injectors and touch negative.

should i hook up the resistor pack with the firing order? like the 7M is.

ugh.. this is taking forever, lol


http://www.youtube.com/watch?v=Qxxju5JcLcc

 

[annoyingrob]

Seriously guys, did nobody notice that he said the crank was 4* off from TDC? Cams and crank must all be at TDC at the same time. This alone will cause some fun issues.

As for only running one pump, most fuel pumps have a 1-way valve in them to prevent the line draining when the car is off. Running only one pump should pose no problem.

Third, holy crap, upgrade that wiring. The two pumps combined at high pressures will be pulling in excess of 30A. Hell, the stall current of the stock pump is like 18A. Two aftermarket ones, you'er looking at a lot of current. Way too much current for that little wire you had. This would be why it burned up. Run your pumps off of the battery through a relay, period. If you don't want to run the wire through your car, run it underneath, with the fuel and brake lines. There's a plastic shield you can slide the wire in.

I run 12ga underneath the car for my two pumps.

 

[crazysupra2JZ]

Seriously guys, did nobody notice that he said the crank was 4* off from TDC? Cams and crank must all be at TDC at the same time. This alone will cause some fun issues.

As for only running one pump, most fuel pumps have a 1-way valve in them to prevent the line draining when the car is off. Running only one pump should pose no problem.

Third, holy crap, upgrade that wiring. The two pumps combined at high pressures will be pulling in excess of 30A. Hell, the stall current of the stock pump is like 18A. Two aftermarket ones, you'er looking at a lot of current. Way too much current for that little wire you had. This would be why it burned up. Run your pumps off of the battery through a relay, period. If you don't want to run the wire through your car, run it underneath, with the fuel and brake lines. There's a plastic shield you can slide the wire in.

I run 12ga underneath the car for my two pumps.

in the morning i will zero it out. it's crazy how just a little bit can cause this kind of issue, if it's the fix, i doubt it though, there are a lot of problems causing this i bet. so far i made like 5 changes that helped out a little each time.

right now i have 10 awg wire up until it reaches the wire that walbro uses for the clip, know what i mean. the most the pressure goes, cause i can't build any boost... is 40 psi. it seems to run fne with one pump. i think it will be safe to boost up to 15 psi like this.

i'm having a hard time tuning with the AFC NEO. i have the Lo throttle at 15% and Hi at 60%. my understanding is when i'm below 15% throttle it will use the Lo throttle settings i make, then after 60% it uses Hi settings.


***** well, i got it as best i could, no difference. i give up... when i get back from deployment i might mess around with it. i'm gonna start saving for an MKIV, i should have about $6k saved up by december from deploying. that's half of what i need to get one, i'll probably swap the 2jz in my 89 into the mkiv. and start from scratch.

 

[crazysupra2JZ]

i just thought of something

i don't know if the O2 sensor i'm using for the ECU is the right one. i'm using a universal O2 sensor that was pretty cheap, i think less than $25. it only has one wire out of it, supra wasn't in the list of cars it was designed for. last time when i did this i used a sensor that came up in the search at advanced auto for a 94 supra, i paid $80 for it, it had 4 wires coming out of it. it did the job.

maybe this whole problem is the O2 sensor. is there a way to check to see if it's getting the correct signal? i don't want to spend $80 on something that isn't the problem,

 

[tlo86]

could do it. if you arent building boost it is a timing issue