Engine not running

Tiny
THE SALMON
  • MEMBER
  • 1999 GMC YUKON
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 207,000 MILES
I just completed the replacement of both head gaskets and a valve job. After I finished and tried to start the engine, it would not start. I know the timing is on. Checked compression and found I had 0 psi. I'm thinking I tightened the valves too much. I have taken off the valve covers to re-adjust the valves according to the GMC manual. (I've done this 6 times before and the last time was 20 years ago!) I believe I made a mistake!
I do not see any bent push rods or bent/broken valves.
Will over tightening the valves cause 0 compression?
Thanks in advance.
Carl
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Tuesday, December 31st, 2019 AT 2:08 PM

62 Replies

Tiny
SCGRANTURISMO
  • EXPERT
Hello,

I don't believe so, and if it did you would have a bent valve and/or bent pushrod. Did you lap the valves into the cylinder head valve seats?

Thanks,
Alex
2CarPros
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Tuesday, December 31st, 2019 AT 4:18 PM
Tiny
THE SALMON
  • MEMBER
Yes I did. I'm going to try to adjust the valves using the GM repair manual. I did adjust them using their method, but went 360 again, a quarter turn at a time, and tightened them again! After I adjust them again I'll shoot air into the cylinder and feel or hear for leaks.
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Tuesday, December 31st, 2019 AT 6:02 PM
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

Okay, so in the diagrams down below I have included the specs. For the valves on your vehicle's engine and the instructions from the vehicle manufacturer on the procedure for adjusting the valve lash. Please go through these guides and get back to us with what you find out. Also, did you use the same head bolts when you reinstalled the heads on the engine block? I have found doing a search of Technical Service Bulletins[TSB][s] for your vehicle one that deals with the head bolts. Please get back to us with how things are going.

Thanks,
Alex
2CarPros
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Wednesday, January 1st, 2020 AT 12:03 AM
Tiny
THE SALMON
  • MEMBER
Hello again!
Yes. I used new head bolts. I have the same manual as you are showing. I'll let you know when completed.
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Wednesday, January 1st, 2020 AT 9:18 AM
Tiny
TOUGHDIVER
  • EXPERT
Hi,

The best way to adjust valves is to start on number 1 cylinder TDC loosen both intake and exhaust rocker arms so there is plenty of free play hold the push rod with two fingers and rotate the push rod between your fingers as you tight the rocker arm until you have resistance than stop that valve is adjusted. Do this in firing order each cylinder at a time and the vehicle will start. (The best way is to adjust valves is with the valve covers off vehicle running). Let us know if this info. Was helpful and if it fixed your vehicle.

Thank you
Joe T.
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Thursday, January 2nd, 2020 AT 4:45 PM
Tiny
THE SALMON
  • MEMBER
I've adjusted the valves per the GM repair guide and I now have compression in every cylinder! I've put it all together but will not try to start it until the distributor arrives. Hopefully tomorrow! I believe it will start now as it is cranking more freely and have good compression in all cylinders.
I'll let you know.
Thanks to everyone for the help, it's much appreciated!
Carl P.
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Thursday, January 2nd, 2020 AT 7:09 PM
Tiny
KEN L
  • ADMIN
You are welcome, DUFFDIVER is one of our newest experts, he is quickly shaping up to be one of our best!
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Sunday, January 5th, 2020 AT 1:09 PM
Tiny
THE SALMON
  • MEMBER
I had to go out of town until Thursday. I had bought many new parts during the rebuild, except for the distributor! (My memory must be fading as I get older)! Anyway, it will be waiting there when I get home. I mentioned that I checked after re-adjusting the valves that I had good compression so I'm sure it will start and run great. I'll follow up when I'm done.
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Monday, January 6th, 2020 AT 11:25 AM
Tiny
TOUGHDIVER
  • EXPERT
Thank you look forward to hear from you.
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Monday, January 6th, 2020 AT 1:33 PM
Tiny
THE SALMON
  • MEMBER
I knew I should have looked at the new distributor that was delivered before I went out of town. It was for a 1980's Chevrolet! Anyway, using the old distributor and guessing on timing, I turned the key and it fired right up! No ticking, knocking or backfiring! It sounds like new! Only issue I have is that when I replaced the timing chain, I probably should have dropped the oil pan so that I could have put a lot of gasket sealant where they butt up against each other, because I have an oil leak there (Dammit)! I tried spraying some sealant there but no dice! I'm gonna pull off the fan again so I can get a closer look at the cover to make sure the leak is in fact there. I torqued the timing chain cover to GM specs so that should not be an issue. I am getting a code for the crank position sensor, but I believe that is because the timing is out. It does drive great, though. I need to take it to a garage, because my scanner does not have the Cam retard option, so they will need to set the timing.
Thank you everyone for your help, It was much appreciated.
Carl P
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Sunday, January 12th, 2020 AT 12:13 PM
Tiny
KEN L
  • ADMIN
Nice work, we are here to help, please use 2CarPros anytime.

Please post your new question here, you must be logged in:

https://www.2carpros.com/questions/new

Cheers, Ken
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Monday, January 13th, 2020 AT 11:44 AM
Tiny
NAILZ
  • MEMBER
  • 1999 GMC YUKON
My 99 Yukon has trouble starting. Doesn't matter time, temperature, time since last started. Once it is running, it runs great!
Items replaced so far: throttle positioning sensor, coil, rotor, dist cap, spark plugs.
Most of the time manipulating the gas pedal will help it start. But sometimes it won't start at all. Wait a few hours and it starts right up. I am lost and will appreciate all help.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
SMOKINFLOYD4.3
  • MEMBER
It could be the fuel pump, sounds like a 92 gmc safari van I had to fix for a friend
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
NAILZ
  • MEMBER
Yeah, guess that I forgot to list that. New fuel pump too.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
SMOKINFLOYD4.3
  • MEMBER
Dont you hate the parts throwing game? It damn sure aint cheap. Have a crank sensor on that truck?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
NAILZ
  • MEMBER
Don't know, I am sure it does. You think this could be the problem? I'll check into it.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
NAILZ
  • MEMBER
Ok, I believe that your right on the fuel pressure regulator. Problem is that I couldn't figure out where it is. Looked all around the manifold by the fuel rails and couldn't find anything. Anyone where to look for this thing and maybe some tips on replacing it?

Thanks
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
RON1MOONEY
  • MEMBER
  • 1999 GMC YUKON
  • 190,000 MILES
1999 GMC Yukon 5.7 2WD intermittently will not start. After a few hours of sitting it starts again like nothing was wrong. It may perform fine for days, weeks, and months and then fail again only to work again after sitting for hours with no worked performed. The engine turns over just fine but is not getting fuel. In the beginning I changed the fuel pump (three times). But as I changed the fuel pump each time it checked out fine. I have checked all the fuses and they are good. I have changed and checked the fuel pump relay and it is good. Using a wiring diagram I have seen the next component to check that controls the fuel pump is the Vehicle Control Module (VCM). The way I read the wiring diagram I should be able to apply 12V to the 87A socket on the relay board and start the fuel pump prime, is that correct? Am I on the right track? I see literally thousands of post about this issue with 90 model GMCs but have not seen a satisfactory solution.
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
DRHERMAN
  • MEMBER
I am experiencing a similar problem to yours. The truck starts immediately when cold, runs great. Occassionally (every couple of days) the car will fail to start when hot. Allowing 2-4 hours cooldown, it will start right up. Any suggestions? Could this be a fuel pump issue; or would it just stop altogether?
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Monday, January 13th, 2020 AT 12:49 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Did you change the connector at the fuel pump module?

Roy
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Monday, January 13th, 2020 AT 12:49 PM (Merged)

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