Too Lean Bank one?
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Too Lean Bank one? What can cause this:
1. bad injectos
2. Bad fuel pump, bad PCM
3. exaust leak, bad valve spring
4. bad O2
5. All of the above
6. None of the above?
Car stumbles at 3100 but recovers. Lost power - feels like a Vega ...seems to hit on all eight but not really sure...
Replaced plugs - no help!
What is the correct fuel pressure at the rail?
1. bad injectos
2. Bad fuel pump, bad PCM
3. exaust leak, bad valve spring
4. bad O2
5. All of the above
6. None of the above?
Car stumbles at 3100 but recovers. Lost power - feels like a Vega ...seems to hit on all eight but not really sure...
Replaced plugs - no help!
What is the correct fuel pressure at the rail?
Fuel pressure should be 50-60 psi. Could be a bad O2 sensor. Trash in the fuel rail. Bad ground on the wire harness. I had a similar problem that plagued me for three months on my 5.3. Except mine would intermitently run lean and stumble and sometimes run great. Making it extremely hard to diagnose. I replaced the o2 sensors, the fuel filter, the fuel pump, all 8 injectors and fuel rails, the pcm, the underhood fuse block, and last but not least the complete wire harness. After changing the wire harness the problem went away. Since all the injectors on one bank share the same ground, I'm led to believe a bad ground was my culprit. Wish you luck.
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Where is the ground on the wire harness; is this at the back of the head on the driver side (Bank 1)?
Where should I start?
I'm thinking:
1. Check ground wires
2. Check fuel pressure at rail
3. Check exhaust leaks - Bank one
4. Swap O2s left to right
5. Swap Bank One and Bank Two fuel injectors
Where should I start?
I'm thinking:
1. Check ground wires
2. Check fuel pressure at rail
3. Check exhaust leaks - Bank one
4. Swap O2s left to right
5. Swap Bank One and Bank Two fuel injectors
The ground on the truck motors is behind the head, and bolted to the block just ahead of the tranny bellhousing. Probably the same on cars. Sounds like a good starting point for diagnosing the problem, and definately cheaper than buying new parts.
