Author Topic: TJ fuel pump has no power and guages quit?  (Read 4225 times)

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JJ984x4

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TJ fuel pump has no power and guages quit?
« on: October 25, 2010, 10:24:35 PM »
Working on my 98 wrangler auto trans (3 spd 30rh) replacing the TCC. Finished the trans and started to fill w fluid, went to start it and run it threw the gears and it wouldn't start. Went and tried to track down the prob and she has no fuel pressure. Come to find out for some reason the fuel pump has no power going to it...?  Any ideas? I have checked - it has fuel, the fuel pump fuse is good and the fuel pump relay is good. Any thing will help...   Thanks     
 

lanulos89

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Re: TJ fuel pump has no power and guages quit?
« Reply #1 on: October 26, 2010, 05:53:07 AM »
pinched and or cut harness?

Offline sharpxmen

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Re: TJ fuel pump has no power and guages quit?
« Reply #2 on: October 26, 2010, 07:09:26 AM »
do you have spark? did you check the other fuses? (there should also be a main fuse for the PCM)
'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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JJ984x4

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Re: TJ fuel pump has no power and guages quit?
« Reply #3 on: October 26, 2010, 08:03:26 AM »
Checked all fueses as far as I know, the fuse block under the hood by the batt and the fuse block behind the glove box. I have looked around where I was working on the trans and have found no pinched wires. The only thing I havnt checked is to see if when I lifted it some thing got pinched. (to lift it I drove it up a ramp until the front drivers side corner was about 2 1/2 ft off the ground) and I can't imagine that that little amount of flex would kill power to the pump. I will continue on it today and keep an eye on the forum. Thanks for your thoughts
 

JJ984x4

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Re: TJ fuel pump has no power and guages quit?
« Reply #4 on: October 26, 2010, 08:10:43 AM »
And yes I do have spark just no power to fuel pump and the guages quit from what I can tell ( the fuel guage and voltage don't budge when I cycle the key) the oil pressure guage does move when I spin it over but that's the only guage i have seen move

Offline sharpxmen

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Re: TJ fuel pump has no power and guages quit?
« Reply #5 on: October 26, 2010, 12:32:08 PM »
And yes I do have spark just no power to fuel pump and the guages quit from what I can tell ( the fuel guage and voltage don't budge when I cycle the key) the oil pressure guage does move when I spin it over but that's the only guage i have seen move

just another thought - check the crank sensor and make sure it's plugged in, although you shouldn't have spark if it was unplugged or out of place

see if you have power to the relay (on both the high current side as well as the command side). You can also try to jump the relay (remove the pump relay and power the pump directly) to see if it starts or not
'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

JJ984x4

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Re: TJ fuel pump has no power and guages quit?
« Reply #6 on: October 26, 2010, 02:18:19 PM »
Have not tried jumping the relay but have sent 12 volts direct to pump and got nothing. So I will try jumping and see if there is any power at the pump connector. but If I get no power at the pump connector what exactly is between the relay and the pump and/or between the ign. Switch and relay that could be @$€#¥£ up?
I've got to be overlooking some thing.   Thanks  so far  hopefully together we can figure it out   W/out your ideas and thoughts I'm just about ready to give up.  Also is there anything that would kill both the pump and guages at the same time???   

Offline sharpxmen

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Re: TJ fuel pump has no power and guages quit?
« Reply #7 on: October 26, 2010, 02:46:05 PM »
Have not tried jumping the relay but have sent 12 volts direct to pump and got nothing. So I will try jumping and see if there is any power at the pump connector. but If I get no power at the pump connector what exactly is between the relay and the pump and/or between the ign. Switch and relay that could be  (at) $€#¥£ up?
I've got to be overlooking some thing.   Thanks  so far  hopefully together we can figure it out   W/out your ideas and thoughts I'm just about ready to give up.  Also is there anything that would kill both the pump and guages at the same time???  

a general fuse or power would cause that, but since the engine does not start it's hard to tell - not sure if the gauges are powered when you crank the engine, they might not be.

if you say you sent 12 volts to the pump and got nothing then maybe your problem is a ground. If you have good ground then maybe the pump is dead (can't see why but that can one problem)

did you look at the crank sensor to make sure is plugged in and the sensor is in place (bolted on properly)?
EDIT: have a look at the cam sensor too (at the connector i mean)
« Last Edit: October 26, 2010, 02:47:19 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

JJ984x4

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Re: TJ fuel pump has no power and guages quit?
« Reply #8 on: October 26, 2010, 02:58:33 PM »
BOth are pluged in and un touched (cam and crank) have not tested the sensors themself but can't see them just going out (but then again I can't see the PCM or fuel pump just going out while working on the trans) I have taken the day off today (spent the last 4 days 15 hrs a day on it so I needed a break) so figured I'd spend the day on the net poking around I'll return to the banging my head on the fender tomorrow. So  Any ideaS will be explored tomorrow

Offline Jeffy

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Re: TJ fuel pump has no power and guages quit?
« Reply #9 on: October 26, 2010, 04:42:55 PM »
Skimmed this thread but if the gauge and pump aren't working, I'd suspect something with the harness going to the tank.
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JJ984x4

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Re: TJ fuel pump has no power and guages quit?
« Reply #10 on: October 26, 2010, 10:05:19 PM »
Did all trans work w it still in jp no pinched wires that I have found but I Will keep looking. Thanks
        Justin

Offline sharpxmen

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Re: TJ fuel pump has no power and guages quit?
« Reply #11 on: October 26, 2010, 10:43:23 PM »
Did all trans work w it still in jp no pinched wires that I have found but I Will keep looking. Thanks
        Justin

check to see if the pump relay has 12v output when you crank it - that way you'll know if it's a problem before or after that relay and go from there.
'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

Offline Jeffy

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Re: TJ fuel pump has no power and guages quit?
« Reply #12 on: October 26, 2010, 11:09:28 PM »
Yeah, you're going to have to check them with a VOM.  I'm gonna guess an open-circuit someplace.  If you can't find a connection to tap, you can always shove a small pin through a wire to get a reading from.  Like Sharp said, start at the relay and work back.
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"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

JJ984x4

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Re: TJ fuel pump has no power and guages quit?
« Reply #13 on: October 30, 2010, 05:40:48 PM »
Ok worked on it a bit today... The fuel pump fuse blows every time I cycle the key. I checked it the other day and it was fine checked it today and it's blown. The relay is good, and when I jump across the relay the pump runs great. Got a short somewhere that will have to wait till next week sometime   Me and a VOM

cz777

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Re: TJ fuel pump has no power and guages quit?
« Reply #14 on: October 31, 2010, 10:50:54 PM »
i had something like this happen to me !the relay pack was bad -both relays gave up their soul and corrosion in the connections as well..........