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No Voltage to Fuel Pump

Tiny
DANIJO123
  • MEMBER
  • 1995 TOYOTA TACOMA
  • 2.4L
  • 4 CYL
  • MANUAL
  • 102,000 MILES
Hello,
Hoping you can help me out, I can usually hear my fuel pump when I turn the key to on position and now I hear nothing, truck will crank over but wont stay running. I checked all Fuse's and EFI Relay and even switched the Tail light relay for the EFI and still checks out ok. Took the gas tank down and Fuel Pump out and gave it power and it turns on but when checking the wiring harness that goes to top of Fuel tank and Fuel Pump and No Voltage with Key in On position. Read elsewhere to check it with vehicle started but thought to ask here. This all started 2 days ago after getting Gas, the check engine light came on.
Thank You
Dan
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Monday, September 5th, 2016 AT 6:16 PM

20 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The first thing you need to understand is the pump only powers for 2 seconds and then shuts off when the key is turned on so don't expect to find power constantly.

Here is the wiring diagram to track the problem down.

http://i1198.photobucket.com/albums/aa448/Wrenchtech/62614214.gif

http://i1198.photobucket.com/albums/aa448/Wrenchtech/62614215.gif

https://www.2carpros.com/images/external/62614216.gif
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Tuesday, September 6th, 2016 AT 4:43 AM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
Hello again
sorry took so long to get bk 2 you. Finally got an OBD2 scanner and got a code of P0100 so on that we replaced MAF and still no start then using starter fluid spray were able to get it started then another code of PO110 just afraid if replacing another part is going to help or not.
Please advise
thank you
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Tuesday, September 13th, 2016 AT 3:44 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
That sensor can cause a lean mixture but I've never seen a MAF cause a no start.
The IAT is on the air filter box so make sure you plugged it back in while you were changing the MAF or you didn't turn the key on while it was unplugged.
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Tuesday, September 13th, 2016 AT 3:50 PM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
Well seems if we try starting fluid the car cranks over but then stalls, only other thing I can think of is the fuel filter but its late will try a go on it tomorrow morning.
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Tuesday, September 13th, 2016 AT 9:48 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,722 POSTS
Please let us know what you find so it will help others.

Best, Ken
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Wednesday, September 14th, 2016 AT 6:13 PM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
Well we replaced fuel filter put everything back together and it cranks but wont start. Also wanted to ask about the fuel pump we have no voltage going to fuel pump with key on, so does it get voltage only when started? And we dont hear it with key on. Changed spark plugs, dist and rotor, MAF, fuel filter. Will only start when spraying starter fuild then stalls after.
Frustrated
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Thursday, September 22nd, 2016 AT 1:57 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
What is your fuel pressure?
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Thursday, September 22nd, 2016 AT 2:40 PM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
Trying to borrow a fuel pressure gage as we dont have one and no funds to buy one at this time with all the new parts we bought. We have seen online how to ck it w/o one but really dont want to chance it
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Thursday, September 22nd, 2016 AT 3:18 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
You can't diagnose a fuel supply problem without a fuel pressure gauge. Many auto parts stores rent or loan them out.
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Thursday, September 22nd, 2016 AT 3:25 PM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
We are waiting on getting a ride to auto store for monday hopefully. We did check for spark and notice the spark was weak and orange in color not blue as they say, battery is cool 13.8v anything else we can check while we wait?
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Monday, September 26th, 2016 AT 1:44 AM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
No Fuel Pressure =(
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Thursday, September 29th, 2016 AT 11:50 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
OK, you're back to using the wiring diagram I gave you earlier to track down why you don't have fuel pressure. Remember, when you are testing for power to the fuel pump, it only power during cranking. Also, make sure you have spark and injector pulse to eliminate other reasons for the pump not running.
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Thursday, September 29th, 2016 AT 12:00 PM
Tiny
DANIJO123
  • MEMBER
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We do have spark, used spark tester over 10k V will ck injector pulse next. Im a 58yr old woman trying to do this, really frustrating lol
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Thursday, September 29th, 2016 AT 12:53 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
It's not your issue now but you should have more like 30-40K on a spark tester.
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Thursday, September 29th, 2016 AT 1:13 PM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
Sorry took so long had to get tools for all this no around here had what I needed. I have Injector pulse, and spark. So is it the fuel pump?
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Monday, October 24th, 2016 AT 10:09 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Not until you have verified power and ground arriving at the pump.
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Monday, October 24th, 2016 AT 10:15 AM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
I tried a digital meter and could not get a reading, think its not getting a reading cause it primes too fast going to try analog meter to try does this make sense?
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Friday, October 28th, 2016 AT 8:51 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
You will only see power to the fuel pump for 2 seconds when the key is first turned on and again during cranking when the computer see the RPM signal.
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Saturday, October 29th, 2016 AT 4:30 AM
Tiny
DANIJO123
  • MEMBER
  • 11 POSTS
Trying to verify voltage to pump from the connector on top of the tank unplugged of course being that it primes so fast a digital meter does not capture it. So i'm going to try an Analog meter that's what I was asking if that made sense. You have already told me about how much time it takes to prime, An Analog meter with a swinging needle is what I will try, turning the key on and off will it keep priming?
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Saturday, October 29th, 2016 AT 8:54 PM
Tiny
WRENCHTECH
  • MECHANIC
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A digital meter has always worked for me. You just have to be looking at it when a helper turns the key on. The power feed wire will be blue and the ground wire will be white with black.
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Sunday, October 30th, 2016 AT 4:06 AM

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