Stumbles - too lean code - what fuel pressure?
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Stumbles - too lean code - what fuel pressure? OK my car is running ruff for weeks. Finally, a code triped - Too lean, Bank One. It kinda shuts off at 3100 RPM and then resumes past that. Power is lower than normal.
I just replaced pugs, wires - no help.
Yesterday, it stumbled bad on acceleration and almost dropped dead. Then it was OK.
So what could be the issue:
1. Bad injector
2. Bad fuel pump
3. exhaust leak
4. Bad front O2 cable splice
5. PCM going south
6. Coil pack bad?
Rear O2s are turned off w/LS1Edit - LT headers.
I would like to check the fuel pressure at the fuel rail. What is normal? This is a constant fuel pressure system that does not vary with RPM; right?
I just replaced pugs, wires - no help.
Yesterday, it stumbled bad on acceleration and almost dropped dead. Then it was OK.
So what could be the issue:
1. Bad injector
2. Bad fuel pump
3. exhaust leak
4. Bad front O2 cable splice
5. PCM going south
6. Coil pack bad?
Rear O2s are turned off w/LS1Edit - LT headers.
I would like to check the fuel pressure at the fuel rail. What is normal? This is a constant fuel pressure system that does not vary with RPM; right?
Originally Posted by robertbartsch
I would like to check the fuel pressure at the fuel rail. What is normal?
Originally Posted by robertbartsch
This is a constant fuel pressure system that does not vary with RPM; right?
Normal Fuel Pressure is 55 to 60 psi.
Most generally a lean code is indicative of a bad O2 or a MAF issue, but you need to verify with a scan tool that everything is working properly first.
Most generally a lean code is indicative of a bad O2 or a MAF issue, but you need to verify with a scan tool that everything is working properly first.
Let me know when you figure this out. I'm dealing with a similar problem. Car started running rough and was getting worse. When changing plugs, #8 was fouled bad, and the car ran better for a little while. When missing started again, I pulled #8 and it was fouled again. I've changed the plug and the wire with no luck. I'm getting the same code as you only bank 2. I'm hoping its the coil pack on #8 but won't know until the new one gets here tomorrow.
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Verdad Gallardo Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
OK - so this is what I did on Sunday:
1. Replaced Bank 1 O2 sensor with new rear Vette O2
2. Pulled Cat - and checked for LT header collector air leak
3. Checked header bolts (OK)
4. Re-tightened intake bolts (loose)
5. Re-checked Bank 1 plug wires
6. Re-checked PCV plug on back on Bank one valve cover (loose)
7. Removed plastic bag from radiator
8. Checked bolts on air pump (OK)
9. Cleared PO171 (Too lean Bank 1) code with scanner
Results:
The car picked up ALL the lost horsepower it lost several months ago
I was very pleased
After I drove the car several times the PO171 code, returned on the scanner (no MIL light yet)
The car stumbled again too - the first few times I drive it no stumble, however.
So here is what I plan to do next:
1. Replace Bank 2 - O2 sensor (this cable harnice is sliced with an 6 inch extension)
2. Pull the manifold and replace the intake gaskets.
3. Swap Bank 1 and Bank 2 injectors
4. Re-check the ground wires on drivers side cylinder head
5. Swap the aftermarket MAF for the factory MAF
You guys have an other ideas?
Thanks...
1. Replaced Bank 1 O2 sensor with new rear Vette O2
2. Pulled Cat - and checked for LT header collector air leak
3. Checked header bolts (OK)
4. Re-tightened intake bolts (loose)
5. Re-checked Bank 1 plug wires
6. Re-checked PCV plug on back on Bank one valve cover (loose)
7. Removed plastic bag from radiator
8. Checked bolts on air pump (OK)
9. Cleared PO171 (Too lean Bank 1) code with scanner
Results:
The car picked up ALL the lost horsepower it lost several months ago
I was very pleased
After I drove the car several times the PO171 code, returned on the scanner (no MIL light yet)
The car stumbled again too - the first few times I drive it no stumble, however.
So here is what I plan to do next:
1. Replace Bank 2 - O2 sensor (this cable harnice is sliced with an 6 inch extension)
2. Pull the manifold and replace the intake gaskets.
3. Swap Bank 1 and Bank 2 injectors
4. Re-check the ground wires on drivers side cylinder head
5. Swap the aftermarket MAF for the factory MAF
You guys have an other ideas?
Thanks...
Is the lean code for one side or both sides?? That could help narrow it down. I had two lean codes...one for each side. I figured out that I had a vaccuum leak. I had the intake manifold off about 1 week prior to throwing the codes, and I guess it didn't seal up right when I put it back on.
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
Nah.... I think there are separate codes for "too lean Bank 1" and "too lean Bank 2"
Anyway, I had the intake off 12 months ago to replace the cam sensor. On Sunday I tightened up the intake bolts - they were loose.
I supose it could be a intake gaskets so manybe I will pull it and try that. If I pull the intake I can get at the electrical ground wire that is bolted to the driver head; right?
Anyway, I had the intake off 12 months ago to replace the cam sensor. On Sunday I tightened up the intake bolts - they were loose.
I supose it could be a intake gaskets so manybe I will pull it and try that. If I pull the intake I can get at the electrical ground wire that is bolted to the driver head; right?
