bubba68ss
March 2nd, 2013, 09:33 PM
Picked up a ZR2 Blazer with a rod knock, put my rebuilt 4.3 from my truck in it, got it running but it's a bit shaky at idle.
Here are the symptoms;
- bank 1 has sooty plugs while bank 2 has normal clean plugs
- LTFT on bank one is reading 25 while bank 2 is about 4 (normal)
- Idle rough (shaky) but drives
- engine smooths out and runs nice as RPM's rise but lacks a little power.
This is a fresh rebuild and I can't find any vacuum leaks. If it were a vacuum leak, wouldn't both banks be getting too much air since they feed off the same intake?
Am I looking at a bad O2 sensor which is telling the PCM that bank 1 is lean and it is dumping lots of extra fuel trying to compensate? O2 on bank 1 is reading low numbers while the O2 on bank 2 reads throughout it's normal range.
What's the best way to diagnose this using my tuning equipment?
Here are the symptoms;
- bank 1 has sooty plugs while bank 2 has normal clean plugs
- LTFT on bank one is reading 25 while bank 2 is about 4 (normal)
- Idle rough (shaky) but drives
- engine smooths out and runs nice as RPM's rise but lacks a little power.
This is a fresh rebuild and I can't find any vacuum leaks. If it were a vacuum leak, wouldn't both banks be getting too much air since they feed off the same intake?
Am I looking at a bad O2 sensor which is telling the PCM that bank 1 is lean and it is dumping lots of extra fuel trying to compensate? O2 on bank 1 is reading low numbers while the O2 on bank 2 reads throughout it's normal range.
What's the best way to diagnose this using my tuning equipment?