98 Silverado 5.0 305/thought it was timing chain
October 25th, 2011, 7:37 AM
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98 Silverado 5.0 305/thought it was timing chain
Started my truck Sunday morning and it was like it jumped time. Ran bad, could barely keep it running and crippled it home from church about 1 1/2 miles. It was kicking and bucking and popping back through the intake. Having never had to tear down a fuel injected system, I immediately reverted to what I know about older chevies. Sounded and acted just like a timing chain. The engine has about 180K on it and has run good up to this point. I tore it down yesterday, found the chain to be very loose, and replaced it. That didn't fix it. Does anyone have specifics of what particular electronics on this vehicle might cause this problem? It does have some sort of trigger and switch that work off of the crank and I'm not sure what it controls. I also replaced the dist cap and rotor. Thanks
October 25th, 2011, 8:07 AM
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Sorry to hear that
It might be something with the EGR valve or some other sensor maybe. I remember for a few years in the late 90's the EGR valves caused problems liek you explained.
October 25th, 2011, 11:58 AM
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going to borrow a code reader and check it after work today. I was hoping someone had this very same thing happen and shed some light. Thanks
October 26th, 2011, 6:32 AM
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the crank sensor failed on mine and thru the timing out far enouph to destroy a flex plate and a starter i cut and pasted the bulletin
Engine - No/Hard/Slow Start/Backfire/Kickback
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 00-06-04-014
Date: April, 2000
TECHNICAL
Subject:
No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338
(Replace Crankshaft Position Sensor)
Models:
1999-2000 Cadillac Escalade
1995-2000 Chevrolet and GMC SIT Models
1996-2000 Chevrolet and GMC C/K, M/L, G, P Models
1996-2000 Oldsmobile Bravada
with 4.3 L, 5.0 L, 5.7 L or 7.4 L Engine
(VINs W, X, M, R, J RPOs L35, LF6, L30, L31, L29)
Condition:
Some customers may comment on one or more of the following conditions:
^ Backfire during crank/start
^ "Kickback" during crank/start
^ "No" start
^ "Slow" or "hard" start/crank
^ "Grinding" or unusual noises during crank/start
^ Cracked or broken engine block at the starter boss
^ Broken starter drive housing
^ Broken starter ring gear on flywheel
^ Any combination of the above
Cause:
A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.
Correction:
Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the "Service Engine Soon" light. If this code is stored, the Crankshaft Position Sensor, P/N 10456607, MUST be replaced and the remaining components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).
Notice : When DTC code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated inoperative conditions of the starter or flywheel.
Important : Some flywheel wear is normal; broken or missing teeth and/or cracks, are not normal.
Parts Information
Parts are currently available from GMSPO.
Warranty Information:
Engine - No/Hard/Slow Start/Backfire/Kickback
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 00-06-04-014
Date: April, 2000
TECHNICAL
Subject:
No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338
(Replace Crankshaft Position Sensor)
Models:
1999-2000 Cadillac Escalade
1995-2000 Chevrolet and GMC SIT Models
1996-2000 Chevrolet and GMC C/K, M/L, G, P Models
1996-2000 Oldsmobile Bravada
with 4.3 L, 5.0 L, 5.7 L or 7.4 L Engine
(VINs W, X, M, R, J RPOs L35, LF6, L30, L31, L29)
Condition:
Some customers may comment on one or more of the following conditions:
^ Backfire during crank/start
^ "Kickback" during crank/start
^ "No" start
^ "Slow" or "hard" start/crank
^ "Grinding" or unusual noises during crank/start
^ Cracked or broken engine block at the starter boss
^ Broken starter drive housing
^ Broken starter ring gear on flywheel
^ Any combination of the above
Cause:
A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.
Correction:
Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the "Service Engine Soon" light. If this code is stored, the Crankshaft Position Sensor, P/N 10456607, MUST be replaced and the remaining components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).
Notice : When DTC code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated inoperative conditions of the starter or flywheel.
Important : Some flywheel wear is normal; broken or missing teeth and/or cracks, are not normal.
Parts Information
Parts are currently available from GMSPO.
Warranty Information:
October 26th, 2011, 7:31 AM
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Sean, very similar problem with what is happening to my truck. When I crank the engine it's almost like something just locks the motor at times and it won't crank. I will check that also. When I ran the codes on my truck, it came up with about 6 pages of information and enough possibities of problems to fill a book. Thanks
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October 26th, 2011, 12:58 PM
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