First time in 115k miles: Good crank, slow start
Thread Starter
Safety Car
Joined: Dec 2006
Posts: 4,574
Likes: 1,651
From: Pearland / Houston Tx
First time in 115k miles: Good crank, slow start
07 Base LS2
No luck searching for an answer. Went to start it, just cranked and cranked until I shut off. Normal fast crank, battery is on a tender.
Went to start again, cranked for couple seconds then fired up, bogging down like an old flooded carburetor. Cleared up after a few seconds and ran normal. Down block and back and it restarted fine.
I woud suspect some fuel pressure issue but the way it chugged before clearing up and running normal seems like too much fuel.
No codes pending or set. Plug wires are tight. Could put a fuel pressure gauge on but doubt find anything. Car sat for 2 weeks which is longer than I normally go between startups.
Anybody?
No luck searching for an answer. Went to start it, just cranked and cranked until I shut off. Normal fast crank, battery is on a tender.
Went to start again, cranked for couple seconds then fired up, bogging down like an old flooded carburetor. Cleared up after a few seconds and ran normal. Down block and back and it restarted fine.
I woud suspect some fuel pressure issue but the way it chugged before clearing up and running normal seems like too much fuel.
No codes pending or set. Plug wires are tight. Could put a fuel pressure gauge on but doubt find anything. Car sat for 2 weeks which is longer than I normally go between startups.
Anybody?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,418
Likes: 3,974
From: Cape Coral, Florida
07 Base LS2
No luck searching for an answer. Went to start it, just cranked and cranked until I shut off. Normal fast crank, battery is on a tender.
Went to start again, cranked for couple seconds then fired up, bogging down like an old flooded carburetor. Cleared up after a few seconds and ran normal. Down block and back and it restarted fine.
I woud suspect some fuel pressure issue but the way it chugged before clearing up and running normal seems like too much fuel.
No codes pending or set. Plug wires are tight. Could put a fuel pressure gauge on but doubt find anything. Car sat for 2 weeks which is longer than I normally go between startups.
Anybody?
No luck searching for an answer. Went to start it, just cranked and cranked until I shut off. Normal fast crank, battery is on a tender.
Went to start again, cranked for couple seconds then fired up, bogging down like an old flooded carburetor. Cleared up after a few seconds and ran normal. Down block and back and it restarted fine.
I woud suspect some fuel pressure issue but the way it chugged before clearing up and running normal seems like too much fuel.
No codes pending or set. Plug wires are tight. Could put a fuel pressure gauge on but doubt find anything. Car sat for 2 weeks which is longer than I normally go between startups.
Anybody?
Sorry but can't diagnose this for you over the Internet...can be a crank or cam sensor...if you have even a code reader see if you have an RPM signal during cranking...if not probably crank sensor...a bad cam sensor can also cause a "hard" or extended crank...this would not cause a "rich" condition though...I'd check fuel pressure also...check that an upstream O2 sensor is not "stuck" lean which can cause an "overfueling" condition and also possible misfires on one bank...also maybe stuck open EVAP purge valve letting in gas fumes from the charcoal canister...just "follow the data" and don't guess...that will get your car running again...try removing the purge line going to the intake manifold and see if starts easier...just seal the fitting on the manifold so you don't have a vacuum leak...moving this to Tech for further discussion.
Last edited by C5 Diag; May 9, 2026 at 12:55 PM.
Drifting
Joined: Jul 2005
Posts: 1,627
Likes: 187
From: Austin TX
Hove and 05 with 113k. Same thing happens if I don't start it for a few weeks. It'll start slow, bog a little then run fine afterwards. Only thing different is if I restart it later that day or within a few days after, no issues. Mightbe the starter going south.
Thread Starter
Safety Car
Joined: Dec 2006
Posts: 4,574
Likes: 1,651
From: Pearland / Houston Tx
The crank is strong. Not a slow start, is a no start... then turn off and then it starts on second try with a flooded intake symptom. I hooked up Tech 2 to see if it shows RPM at crank but has started right up on first push ever since. So I can't duplicate the problem yet.
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