Engine Won't Start has fire has fuel

Tiny
JTGMFAN
  • MEMBER
  • 2004 CHEVROLET SUBURBAN
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 135,000 MILES
Engine has had intermittent miss at idle for a few weeks, and slight hesitation due to the miss from a stop but has not had apparent power loss at engine speeds above idle. I have not had hard starting problems. Today the engine would not start, it just cranks. Crank speed is normal. I pulled #2 and #4 plug wires, both have spark sufficient to jump at least ~1/2 inch gap to the exhaust manifold. I noted that the spark on both cylinders is orange, not white-blue as I expected. Pulled air inlet tube from throttle body and sprayed flammable brake cleaner past open throttle plate, still would not run engine. The theft light comes on solid when key is turned on but does not flash, and goes out when the ignition switch is in the start position. Have not had service engine soon light with the engine miss, but since it will not start the SES light is on now. I don't have a code scanner.
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Monday, January 20th, 2014 AT 2:40 PM

12 Replies

Tiny
HMAC300
  • EXPERT
Try resetting security system first see pic. Then if it still doesn't start get it scanned, check with autoparts they may rent the scanner. Also check fuel pressure with a gauge.
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Tuesday, January 21st, 2014 AT 5:51 AM
Tiny
JTGMFAN
  • MEMBER
I looked at the security system reset procedure, but the indicator light does not stay on after trying to start the engine. I also purchased an Actron PocketScan OBD II reader and fuel pressure gauge today. I scanned for codes and found 0 codes, even though the SES light is on. The code reader says the Malfunction Indicator Light is off. Fuel pressure gauge shows fuel system pressure of 48 lbs.
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Tuesday, January 21st, 2014 AT 5:56 PM
Tiny
JTGMFAN
  • MEMBER
It seems the fuel system pressure is low, but shouldn't the engine run on starting fluid?
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Tuesday, January 21st, 2014 AT 7:40 PM
Tiny
HMAC300
  • EXPERT
Unless you have the "Z " vin code your fuel pressure shold be 55-62 so you probably have a pump problem if you only have 38 psi. Starting fluid won't start them all the time and is really kind of dangerous to use on a gas or diesel engine. If you have the Zvin code then it shold be 48-54 psi which according to you is still low. You may not have a good connection with your tester as well so have a pro check it. Make sure key is on when you read codes.
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Wednesday, January 22nd, 2014 AT 7:05 AM
Tiny
JTGMFAN
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It has flex fuel and I'm seeing 48 lbs, should it be higher? The pressure decreases and does not rebound when the gauge bleed valve is opened with the ignition in the run position.
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Wednesday, January 22nd, 2014 AT 12:48 PM
Tiny
HMAC300
  • EXPERT
If you have the vinZ then the pressure is ok Look on the vin plateon dash and if 8th digit says Z it's ok if not a Z it' sto low. If it is Z and doesn't hold pressure for 5 minutes with in 5psi then you may need a regulator. Otherwise have a pro look at this.
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Wednesday, January 22nd, 2014 AT 12:57 PM
Tiny
JTGMFAN
  • MEMBER
You're talking about the fuel injector pressure regulator, correct?
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Wednesday, January 22nd, 2014 AT 1:31 PM
Tiny
HMAC300
  • EXPERT
Yes I am guess I should have been more specific
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Wednesday, January 22nd, 2014 AT 3:51 PM
Tiny
JTGMFAN
  • MEMBER
No problem, just wanted to make sure. It is a Z engine code.

New development - I put the battery charger on it all day and after work it started right up. There was an SES light after it started but that was P0101 MAF which was because I left the air horn off the throttle body. I installed that and cleared that code and now there is no SES light or code. Turned key to off, put pressure gage back on, turned key to run. The fuel pressure was around 52 psi while the pump was running, then after the pump shut off and after five minutes the pressure dropped to 46 psi, then dropped to 42 fairly quickly, then rose to 50 and held. Then started the engine, pressure was around 46 while running, but the gage needle was vibrating very fast, sometimes over a 10 psi range (40-50psi), sometimes over a 4-6 psi range. Shut the engine off, returned the key to the run position (engine not started) and pressure held steady at 50 psi for five minutes.
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Wednesday, January 22nd, 2014 AT 4:24 PM
Tiny
HMAC300
  • EXPERT
Sounds like you are good to go, keep an eye on the battery however. You can go to an auto parts store and have it tested for condition including load test. If it goes below 12.4 when they hook up tester then the battery shold be replaced. But sounds like you have it now.
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Wednesday, January 22nd, 2014 AT 4:42 PM
Tiny
JTGMFAN
  • MEMBER
Got in the car at lunch and it wouldn't start again. I heard somewhere that WOT bypasses some of the restrictions during startup, so I mashed the pedal to the floor and it started. Took it to the parts house and tested the battery, it was 12.9V with load. It's still running rough at idle but under hard acceleration it doesn't miss a beat. If the pump was bad, would the pressure ever make it to 52psi (when the key is switched on)?
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Thursday, January 23rd, 2014 AT 4:54 PM
Tiny
HMAC300
  • EXPERT
Yes it will go higher as you accelerate but get this scanned for codes I think you have something else wrong.
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Friday, January 24th, 2014 AT 6:43 AM

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