Engine not running

Tiny
RON1MOONEY
  • MEMBER
  • 9 POSTS
Yes I changed it when I changed the fuel pumps.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
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  • 9 POSTS
Can I get another answer please?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
How do you know that you're not getting sufficient fuel. What is the fuel pressure reading when this happens?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
MOYESTOY
  • MEMBER
  • 1 POST
  • 1999 GMC YUKON
Engine Mechanical problem
1999 GMC Yukon Two Wheel Drive Automatic 175000 miles

I have already changed the fuel pump fuel filter and the fuel senser under the hood sometimes it cranks and my run fine for a while and the next time you go to start it all it will do is turn over and will not start.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Next time it refuses to start do below to determine what's causing it and get back with some results we start here.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
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  • 9 POSTS
The car will not start and the fuel pump primer is not coming on. I can normally hear the fuel pump primer come on when I turn the ignition key to the on position but now it is silent.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
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That's what I thought. You need to use a fuel pressure gauge.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
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Not sure I am following you, the car will not start, therefore there is not fuel pressure, the guage will reflect 0, will it not? I need to know what is stopping the electrical current from getting to the fuel pump. I can apply 12v straight to the pump and it turns, the fuel pump relay is good, what stops the signal to the fuel pump relay?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
J.GRAY
  • MEMBER
  • 1 POST
  • 1999 GMC YUKON
  • V8
  • 4WD
  • AUTOMATIC
  • 93,000 MILES
When I turn the key the engine turns over, but that's it.

I've changed the plugs & wires, and the Fuel pump relay.

I've sprayed the the throttle body with starter fluid, and

still nothing.

Some-one told me there may be an issue with a "fuel shut

off switch. The problem is, I don't know where that is

located in my truck.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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I've sprayed the the throttle body with starter fluid, and

still nothing.

If you had spark it will fire up -lets do the ignition system.

Disconnect a sparkplug wire or 2 and ground it to the engine -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, distributor pick-up coil, ignition control module, cam and crank sensors-
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
You don't know that you don't have any fuel pressure. You haven't checked it.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
YELHATS ANDY
  • MEMBER
  • 7 POSTS
In the engine compartment fuse box check ign and ecm fuses if no power have easy fix email coprsweet@yahoo. Com
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
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  • 9 POSTS
For conversation sake, let's say the fuel pressure is 66 lbs at 1200 rpm. What could be telling the fuel pump relay to not engage the primer when the ignition key is turned on? Are there sensors that feed a signal to the VCM or is it a bad VCM?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
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I'm sorry, I don't work that way. I'll let someone else deal with this if they choose to.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
  • MEMBER
  • 9 POSTS
The fuel pump relay is not engaging at the turn of the key. There is no audible click and the fuel pump itself doesn't come on. When I test the fuel pump relay it works fine, I replace it with a new one and it still doesn't engage. I simply want to know what component of the vehicle sends the signal to the fuel pump relay to engage the fuel pump primer when the ignition is turned on to start the car?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
THEMIDGET_76
  • MEMBER
  • 1 POST
  • 1999 GMC YUKON
  • V8
  • 4WD
  • AUTOMATIC
  • 132,000 MILES
I was backing out of my driveway today and it stalled and now it wont start, there is also no electricity getting to any part of the car. I have charged the battery a while.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
GEEBI18
  • MEMBER
  • 25 POSTS
My 96 Yukon did this right after I bought it, pulled up to a gas station and it died and I mean dead. It would not do a thing. The negative battery terminal was loose and caused my problem. Check your cables first.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
http://i1198.photobucket.com/albums/aa448/Wrenchtech/78553822.gif
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
  • MEMBER
  • 9 POSTS
Thank you. So as I read this schematic, the dark green/white wire, at pin 85, coming from the VCM should send an electric signal to the fuel pump relay for 5 seconds when the ignition key is turned on, which sends a signal to pin 87A activating the fuel pump primer connector, then that current stops, the relay flips the other way, activating pin 30 and the current from the orange wire coming from the Underhood fuse block passes through the fuel pump relay to energize the pump during normal operation of the engine. And pin 86 is to a ground. Is that how you see it?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
I will be having no further involvement in this question.
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-1
Monday, January 13th, 2020 AT 12:49 PM (Merged)

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