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Thomas, Chevy Technician
Category: Chevy
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Experience:  certified mechanic for 15 years
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99 chevy tahoe: 5.7 engine wont start,has good spark, smells..cranking

Resolved Question:

99 chevy tahoe, 5.7 engine wont start,has good spark, smells of excess fuel after cranking for short time?
Submitted: 6 years ago.
Category: Chevy
Expert:  Thomas replied 6 years ago.
Hello and welcome to Just Answer! I will do my best to help you fix your automotive problem today. Does it have alot of miles on it? If it has fuel and it has spark, I think the next check you should do is compression. I wonder if the timing chain has jumped time.
Customer: replied 6 years ago.
more info, the engine started fine last saturday, drove to station, filled up with gas, drove home no problem. went out sunday,all it would do is crank no start, did the same thing about a week before also. tried today, engine cranks, no start has 245000 miles?
Expert:  Thomas replied 6 years ago.
Ok lets start over you are sure it has good spark but are you sure it is getting fuel?
Customer: replied 6 years ago.
have not tested fuel system, does have smell of raw fuel at exhaust, fuel filter was replaced this past spring
Expert:  Thomas replied 6 years ago.
Crank on it then pull a spark plug and see if it has fuel on it. That will tell you if your getting fuel but it does sound like you are.
Expert:  Thomas replied 6 years ago.

I have had the crankshaft position sensor cause similar concerns. Since you have had this problem come and go it could be your problem. Chevy has issued a TSB for the sensor here is a copy of it.


Engine - No/Hard/Slow Start/Backfire/Kickback

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 00-06-04-014

Date: April, 2000


No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338
(Replace Crankshaft Position Sensor)


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)


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


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.


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:

For vehicles repaired under warranty, use the table.

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