Author Topic: Can i pull the fuel pump relay to drain gas from the rail?  (Read 731 times)

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MYSTANGT

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Can i pull the fuel pump relay to drain gas from the rail?
« on: January 15, 2010, 11:24:26 AM »
I am doing my injectors later tonight and I was wondering if i can just unplug the fuel pump relay once the car is running and let it idle until it dies in order to drain as much gas as possible from the rail?   ???

If anyone has a injector swap write up for a 2.5L TJ on hand let me know or ill try to search for one (im on my phone so its a meticulous process looking for it thats all, sorry for being lazy but it really is bothersome)   :smokes:

thanks gents!   :thumbsup:

PS - i cant locate the schredder valve - 1997 Wrangler SE 2.5L
« Last Edit: January 15, 2010, 11:25:01 AM by MYSTANGT »

Offline sharpxmen

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Re: Can i pull the fuel pump relay to drain gas from the rail?
« Reply #1 on: January 15, 2010, 11:44:49 AM »
I am doing my injectors later tonight and I was wondering if i can just unplug the fuel pump relay once the car is running and let it idle until it dies in order to drain as much gas as possible from the rail?   ???

If anyone has a injector swap write up for a 2.5L TJ on hand let me know or ill try to search for one (im on my phone so its a meticulous process looking for it thats all, sorry for being lazy but it really is bothersome)   :smokes:

thanks gents!   :thumbsup:

PS - i cant locate the schredder valve - 1997 Wrangler SE 2.5L

you could do that (unplug the relay) but it will not drain all the pressure or fuel out, will die before that - you can try to rev it so it will spin a bit more, that would work better i think but i never tried it.

it's fairly simple to remove and replace the injectors, it's in the FAQ injector thread - in a few words: remove the injector connectors (if you think you might forget which one's which mark them first, they are specific to each cylinder, although the way the harness is should be obvious), remove the pressure line (you only have 1 line, there is no return on TJ), remove the screws that secure the fuel rail to the intake manifold, remove the fuel rail with the injectors attached to it, remove the  securing clips that hold the injectors in place on the rail, replace the injectors with the new ones, put the securing clips back on, etc (prior steps backwards).

put a bit of dielectric grease on the o-rings if you have or just regular grease if you dont, that would help them slide in place.

i don't think you have a schraeder valve on your TJ, if you would it's hard to miss.

you should reset the computer, so better disconnect the battery ground before doing all this.

good luck.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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MYSTANGT

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Re: Can i pull the fuel pump relay to drain gas from the rail?
« Reply #2 on: January 15, 2010, 11:58:07 AM »
Yes, will disconnect the battery as ill be swapping the TB as well. Do i HAVE to disconnect the pressurized line. I dont have any fuel disconnect tools...  :'(

which brings up another question. Should i swap my TPS over to the 4.0 tb?
I know you have to replace the IAC and MAF but im not sure about the tps...i remember with my mustang i didnt and i read somewhere that the each TPS is specific to the TB

Offline sharpxmen

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Re: Can i pull the fuel pump relay to drain gas from the rail?
« Reply #3 on: January 15, 2010, 12:20:37 PM »
Yes, will disconnect the battery as ill be swapping the TB as well. Do i HAVE to disconnect the pressurized line. I dont have any fuel disconnect tools...  :'(

which brings up another question. Should i swap my TPS over to the 4.0 tb?
I know you have to replace the IAC and MAF but im not sure about the tps...i remember with my mustang i didnt and i read somewhere that the each TPS is specific to the TB

dude, don't change 2 things at the same time - fix your problem first. Leave the 4.0 t/b for later - make sure your injector swap fixed your issue.

but to answer your question - yes, you need your TPS and your Idle Air Control (IAC) valve with the housing from the 2.5L - on the YJ they have a specialized torx tool, first time i did it i had to knock the center pins in the screws with a miniature chisel, second time i took the IAC off a t/b i drilled a torx head (i think it's #20 if i remember correctly).

the P/Ns are on the items (IAC valve, IAC housing and TPS) so you can compare that with yours, if they are different then swap (and from what i know they are specific to the motor and PCM flash code).

do the t/b swap after you swapped and tested your injectors, you don't want to deal with issues like stalling, increased revs, won't stay at idle, etc and not know which change caused what

EDIT: i think only the IAC housing needs the drilled torx but you need that off your old t/b so don't cut corners b/c you don't have the tool, find a way to take it off - worst case scenario you can saw a channel on the screws so you can use a regular screwdriver, but that's the ugly way of doing it - would work though
« Last Edit: January 15, 2010, 12:24:32 PM by sharpxmen »
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

MYSTANGT

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Re: Can i pull the fuel pump relay to drain gas from the rail?
« Reply #4 on: January 15, 2010, 12:25:35 PM »
oh of course! I wasnt going to do them at the SAME time. I will swap the injectors 1st see if it helps the way the car runs and then i will swap the TB after.

All in the same day is what i meant, and that day is tomorrow !!!   :dance:

Im :bow: that i see some good results!


Offline sharpxmen

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Re: Can i pull the fuel pump relay to drain gas from the rail?
« Reply #5 on: January 15, 2010, 01:00:33 PM »
oh of course! I wasnt going to do them at the SAME time. I will swap the injectors 1st see if it helps the way the car runs and then i will swap the TB after.

All in the same day is what i meant, and that day is tomorrow !!!   :dance:

Im :bow: that i see some good results!



alright/ok, gotcha - let us know how it goes.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end