Help! Can't find problem of not running
- Thread starter 2000sportv8
- Start date
04_Sport_LS
Dedicated LVC Member
Hmmm...
- seconary chain tensioners replaced, and engine supposedly is in time. Condition of primary tensioners not mentioned... and unknown
- fuel pressure is in spec
- o2 codes showing lean
- exhaust looks like it got hot... a sign of running lean
- harder to start with colder temps... when it needs more fuel... a sign of running lean.
- muffler delete... which can cause a lean condition without a reprogram on the fuel trim.
There IS a theme here.
Are you sure that the primary chains and tensioners are in good shape? As suggested by Joe... a compression test would prove this.
If that checks out... then you most likely have a large vacuum leak.
It could be the brake booster or hose, or check valve, (you never confirmed you actually checked these).
It could be an issue with the intake manifold, (maybe cracked)... or the crankcase vent hose that plugs into the intake manifold.
It could also be a completely failed EGR valve, allowing full flow of exhaust gas back into the intake manifold, (which is basically similar to a vacuum leak).
All of these would cause an extremely lean condition, and cause the symptoms you described in your first post.
- seconary chain tensioners replaced, and engine supposedly is in time. Condition of primary tensioners not mentioned... and unknown
- fuel pressure is in spec
- o2 codes showing lean
- exhaust looks like it got hot... a sign of running lean
- harder to start with colder temps... when it needs more fuel... a sign of running lean.
- muffler delete... which can cause a lean condition without a reprogram on the fuel trim.
There IS a theme here.
Are you sure that the primary chains and tensioners are in good shape? As suggested by Joe... a compression test would prove this.
If that checks out... then you most likely have a large vacuum leak.
It could be the brake booster or hose, or check valve, (you never confirmed you actually checked these).
It could be an issue with the intake manifold, (maybe cracked)... or the crankcase vent hose that plugs into the intake manifold.
It could also be a completely failed EGR valve, allowing full flow of exhaust gas back into the intake manifold, (which is basically similar to a vacuum leak).
All of these would cause an extremely lean condition, and cause the symptoms you described in your first post.
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