Chevy PU wont start

Tiny
MIKEURZ
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I have a 1997 Chevy half ton (5.7L) (135K miles)and the engine service light came on 2 days ago, although it still started. Today it started after cranking a while and then ran rough. Every 20-30 seconds, when idling you would hear the engine almost stall and then return to normal. Thinking it was fuel flow issues, I changed the fuel filter and also changed out the PCV valve. Now it cranks but wont start at all. Any suggestions? Ignition coil? O2 Sensor?
Friday, February 16th, 2007 AT 3:33 PM

28 Replies

Tiny
MIKEURZ
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Forgot to mention, when the truck did start earlier, the engine service light was flashing, not on steady. Dont know if that makes a difference
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Friday, February 16th, 2007 AT 3:38 PM
Tiny
CHEVY22
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Check fire from the coil, check fuel pressure should be 60-66 psi and go from there, if you can check the codes let me know what they are
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Sunday, February 18th, 2007 AT 9:04 PM
Tiny
MIKEURZ
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After a lot of cranking yesterday (battery almost completely discharged) the truck started. When it is idling is runs very smooth. When RPMs increase, the block is bounciing around and I can hear a metal clanging sound. I am getting a code reader in a few days to get more information. Can anyone tell me where I plug the reader in?
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Monday, February 19th, 2007 AT 10:13 AM
Tiny
CHEVY22
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Right under your legs under the dash is the connector, check the codes and let me know before we get into the noise, because what ever is turning the light on may be making it run bad causing this problem

thanks
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Monday, February 19th, 2007 AT 10:22 AM
Tiny
MIKEURZ
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Ok, I hooked up a code reader but there are no codes stored. I think running the battery down completely did not help with this effort. The truck will not turn over at all now. Doesn't even sound like it wants to.
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Monday, February 26th, 2007 AT 9:02 PM
Tiny
CHEVY22
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Put the charger on it overnight and recheck the codes when it is charged, no codes we will go from there
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Monday, February 26th, 2007 AT 9:12 PM
Tiny
MIKEURZ
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I had hooked up a "jump starter" while I was trying to retrieve codes 30 minutes ago. When this is attached I can crank the engine as well. Do you think there is any advantage of leaving it on all night? I dont know too much about the onboard computer but will codes disapear if the battery get completely discharged?
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Monday, February 26th, 2007 AT 9:15 PM
Tiny
CHEVY22
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If the battery is fully discharged yes it will kill the codes

thanks jim
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Monday, February 26th, 2007 AT 9:17 PM
Tiny
MIKEURZ
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OK, since I cannot get the codes, its back to basics. I checked the spark and I seem to be OK there. What is the best way to determine if Im getting fuel to the injectors?
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Friday, March 2nd, 2007 AT 7:05 PM
Tiny
CHEVY22
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THE ONLY REAL WAY IS WITH A FUEL PRESSURE GAUGE, YOU CAN TRY ONE OTHER TEST, CRANK THE ENGINE AND PULL A PLUG AND SEE IF IT IS SOAKED WITH FUEL, THIS MAY INDICATE A CAM SENSOR FAILURE, THE INJECTOR TIMING IS DIRECTLY AFFECTED BY THE CAM SENSOR

LET ME KNOW
JIM
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Friday, March 2nd, 2007 AT 7:28 PM
Tiny
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Two quick questions and Ill give it a try; how long should I crank and if the Cam sensor is not functioning, should there be gas on the plugs or should they be dry?
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Friday, March 2nd, 2007 AT 7:33 PM
Tiny
CHEVY22
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IF THE CAM SENSOR FAILS, THE INJECTORS HAVE A 1 IN 6 CHANCE OF FUELING THE RIGHT CYLINDER AND THEY WOULD BE SOAKED, AS THE SPARK MAY BE THERE BUT TIMING OF THE SPARK AND INJECTORS WOULD NOT BE THE SAME, I F YOU NEED THE FUEL PRESSURE SPEC OR SENSOR RANGES I HAVE THEM, JUST LET ME KNOW I DONT WANT TO OVERWHELM YOU

JIM
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Friday, March 2nd, 2007 AT 7:46 PM
Tiny
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OK, I tried doing that and the plug threads do have gasoline on them after cracnking. Its not like its dripping off but they are wet.
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Friday, March 2nd, 2007 AT 8:15 PM
Tiny
CHEVY22
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PLEASE DO NOT CUT THE EXHAUST OFF OF THE VEHICLE, AND THE CHECK ENGINE LIGHT FLASHING JUST MEANS THERE IS A CODE SET BUT NO HARD CODE,

ARE YOU ABLE TO CHECK FUEL PRESSURE?
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Friday, March 2nd, 2007 AT 8:28 PM
Tiny
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I do not have the equipment to check fuel pressure. What is your opinion of whether the camshaft sensor could be bad, basis my last test?
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Friday, March 2nd, 2007 AT 8:31 PM
Tiny
CHEVY22
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VERY POSSIBLE, AND I KNWO THIS IS TOUGH DOING IT THIS WAY BUT I DONT LIKE TO REPLACE PARTS UNLESS I KNOW THEY ARE BAD, BUT IT COULD BE YOU COULD DO THE OLD WIRE SHAKE ALSO WHILE SOMEONE IS CRANKING AND SEE IF SHE FIRES, AND ACTUALLY DO IT ON THE MAF AND THE TPS IAT AND THE IAC, THE FUEL PRESSURE REALLY NEEDS TO BE CHECKED IN MY OPINION TO RULE OUT AN INJECTOR, REGULATOR OR PUMP FAILURE

JIM
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Friday, March 2nd, 2007 AT 8:41 PM
Tiny
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Is there a port for attaching a fuel pressure gauge to our do I have to break the line apart somewhere (like at the filter)?
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Friday, March 2nd, 2007 AT 8:42 PM
Tiny
CHEVY22
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NO LOOK RIGHT BEHIND THE THROTTLEBODY THERE IS A PORT WITH A BLACK CAP, IF YOUR GOING TO DO THIS I THINK I HAD THE SPEC ON THE FIRST PAGE AND LET THE GUAGE STAY ON FOR A WHILE AND LOOK FOR LEAK DOWN, IF IT DOES WATCH YOUR CLOCK AND JOT DOWN THE INFO FOR ME

JIM
GOING TO GET THE KID SOME ICE CREAM BE RIGHT BACK
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Friday, March 2nd, 2007 AT 8:46 PM
Tiny
MIKEURZ
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I will pick up a gauge tomorrow and give it a try. Also, your acronyms, MAF (mass air flow sensor), TPS (throttle position sensor), IAC (Idle Air Control?), Correct? What is IAT?

Hey thanks so much for your help on this so far. I love doing the troubleshooting. Lets hope this baby fires up soon.
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Friday, March 2nd, 2007 AT 8:49 PM
Tiny
SERVICE WRITER
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Intake air temperature

Looks like a productive thread!
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Friday, March 2nd, 2007 AT 9:01 PM

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