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Engine will not start up?

Tiny
EAGLE2343
  • MEMBER
  • 1997 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 300,000 MILES
Just got done doing head gaskets on my truck listed above vortec motor. It would crank and try but wouldn't start. I sprayed starter fluid into the throttle body and it started. So let me back up just a little bit. After the gaskets were done I went ahead and replaced the fuel pump and strainer it didn't change anything so I did the starter fluid. Then I pulled the fuel filter out and used my air hose and blew it out then put it back on. Also pulled the upper intake off and took the injectors off and pulled out the fuel pressure regulator it has a thin layer of plastic where the holes would be so I used a paper clip and put a hole in all 6 spots. Put everything back together and started the truck and it idles really low rpm and when under the hood with it running it sounds like there's an air leak. I pulled the breather off the throttle body and it has a ton of suction. Is it supposed to have that much? Any help is greatly appreciated.
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Friday, September 27th, 2019 AT 6:03 PM

25 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome to 2CarPros.

If you hear an air leak, chances are it is a vacuum leak even though it has good vacuum. When you have a leak, it throws off the air fuel mixture because you are allowing unmetered air to enter the engine.

The first thing I suggest is to locate the source of the sound. It could be nearly anything, even an air intake tube not properly connected. Here is a link that explains how to check for a leak. Try this and let me know what you find

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

When you turn the key to the on position without cranking the engine over can you hear the fuel pump run in the tank for 5 seconds?

https://www.2carpros.com/articles/car-cranks-but-wont-start

Please run down these guides and report back.

Joe
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Friday, September 27th, 2019 AT 8:01 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
The sound of air is coming through the throttle body itself.
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+1
Saturday, September 28th, 2019 AT 5:32 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Do you have the induction tube connected so it has a reading from the MAF sensor?
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Sunday, September 29th, 2019 AT 4:52 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
Are you talking about the tube that goes from the valve cover to the side of the breather? If so yes I did and even unhooking it it didn't make a difference.
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Sunday, September 29th, 2019 AT 5:26 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Actually the tube between the air filter box and the throttle body.
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Sunday, September 29th, 2019 AT 8:19 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
Okay, yes it was on. It didn't make a difference.
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Sunday, September 29th, 2019 AT 8:55 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome back:

Okay, do you by chance have a live data scanner? Have you confirmed fuel pressure?

If you have a live data scanner, plug it in and first check for codes. If there are none, I need to know if it will still start with starting fluid. Also, I need you to check the engine coolant temp sensor's reading.

Let me know if that is something you have and can do.

Thanks,
Joe
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Monday, September 30th, 2019 AT 7:06 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
Took the plenum back off and put holes in the filter for the fuel pressure regulator and it starts and runs, but has no umph behind it. Gonna try to do compression test tomorrow and check out the spark plugs again.
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Monday, September 30th, 2019 AT 7:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome back:

If that has allowed it to run, I feel it isn't a compression issue. Have you confirmed fuel pressure?

Joe
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Monday, September 30th, 2019 AT 7:57 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
I have no way to check the fuel pressure. I just took the fuel filter off and blew it out with the air hose and put it back on. Could it still be the filter?
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Tuesday, October 1st, 2019 AT 5:52 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
If air blew through it easily, chances are it isn't the filter. I hate to ask this, but I need you to try something that will require you to be careful. Remove the fuel filter and cycle the key to the on position and see if fuel comes out at all. Please have a hose or something to direct the fuel flow from the pump. I have a feeling the pump is bad. If you are uncomfortable doing that, and I understand, we have to check it for pressure.

Joe
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Tuesday, October 1st, 2019 AT 5:18 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
It's a new pump. I did compression test yesterday and the passenger side was between 160 and 175 pounds. Driver side was #1 20. #3 0 #5 160 #7 175. So I loosened the rocker arm nuts on #1 and #3 and redone the compression on the 2 and it read 150 and 165. Would that be a bent or sticky valve?
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Wednesday, October 2nd, 2019 AT 6:12 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome back:

When you loosened the rocker, did it close the valve itself or did you have to do something?
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Wednesday, October 2nd, 2019 AT 7:09 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
Only thing I done was loosened the rocker arm nuts. Yesterday I took the intake off and the intake push rod for #7 was bent.
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Thursday, October 3rd, 2019 AT 6:55 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Wow! That is bent! Was there any noise prior to the issue? Any other issues specifically cylinders 1 and 3 considering those two had basically no compression?

Let me know.

Joe
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Thursday, October 3rd, 2019 AT 5:25 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
No noise. What don't make sense to me is that #7 is where the bent one came from n it had 175 compression. 1 n 3 had compression after I loosened the rocker arm nuts. I took the head completely off today and the 'new' valve seals I just put in was shot on #1 #3 n #7. Got head from junkyard and done the water test it passed. The seals on it are brass and rubber. I'll put picture of them up tomorrow after I get the new ones. I received my injector kit today. Is there a certain way the injectors are supposed to go back in the body?
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Thursday, October 3rd, 2019 AT 6:34 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Welcome back:

It doesn't make sense. Somehow the rockers got too tight on one side and most likely too loose on the other causing the bent push rod. When you put everything together on the head, was everything torqued to spec?

As far as the injectors, the new ones will go in the same as the old ones. What I always do to prevent damage to an o-ring is put a small amount of Vaseline in them.

Let me know if you have other questions.

Take care,
Joe
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Friday, October 4th, 2019 AT 6:09 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
Yes, everything was torqued to spec. It don't matter which way the pins go in? There's no way to mark them.
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Friday, October 4th, 2019 AT 6:16 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
When you say pins, what are you referring to?
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Friday, October 4th, 2019 AT 6:20 PM
Tiny
EAGLE2343
  • MEMBER
  • 14 POSTS
The 2 wires at the top of the injectors.
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Friday, October 4th, 2019 AT 6:35 PM

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