Engine crank but wont start

Tiny
JAKE11913
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
Engine Performance V8 Four Wheel Drive Automatic 110000 miles

i have a 1999 suburban w/5.7L cranks but wont start checked fuel pressure pumps up to 64psi. And then falls to 54 psi. After which pressure bleeds of faster than I have ever seen in the past. Also had ic code and crank sensor code. I suspect the presure regular but have heard it may be the pump.
Thursday, June 17th, 2010 AT 1:19 PM

4 Replies

Tiny
INTERNETMECHANIC
  • MECHANIC
  • 700 POSTS
With the engine cranking, visually check for spark at the plugs, if you haven't already. You should be able to pull a spark plug wire, stick known good plug or spark tester in the boot, ground metal part of plug/tester to metal part of engine, engine cranking, watch for spark.

Here are a few guides to help us get the car fixed

https://www.2carpros.com/articles/how-to-test-an-ignition-system

and

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

and

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

As far as the fuel system,gasoline, 4.3--5.0--5.7, 60--66psi. Should hold at least 26 psi for one minute after key is turned off, according to MOD. So far your fuel pressure looks good.
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Friday, October 4th, 2019 AT 3:42 PM
Tiny
JAKE11913
  • MEMBER
  • 3 POSTS
This has good fuel pressure at 1st but it falls to almost 0 within 1 minute. As far as the engine codes P0336, and the other on was ic circuit voltage low but cant remember the code #. Engine fires but will not start. Im pretty sure this is a fuel system problem. Due to the fuel pressure falling so quickly.
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Friday, October 4th, 2019 AT 3:42 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
You could have two problem's I have seen it where the fuel pressure was bleeding down and it still ran good. You have a code for the crank shaft sensor so let's do this if you haven't checked for spark please do that now. If you have spark then we will concentrate on your bleeding down fuel pressure. If you don't have spark then we will work on that first. Let me know what you find.
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Friday, October 4th, 2019 AT 3:42 PM
Tiny
JAKE11913
  • MEMBER
  • 3 POSTS
Thank you for all the help in diagnosing this problem, a fuel pressure regulator was leaking which fixed the problem, I found out from your guide. Thanks again. This site is great!
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Friday, October 4th, 2019 AT 3:42 PM

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