Regal V6-252 4.1L (1984)
90 RICH EXHAUST READING
This example is the same engine running rich, in this case 90 is the designed limit. Rich exhaust (high oxygen sensor voltage) is indicated.
DIAGNOSTIC NOTE
Block learn and integrator numbers displayed an a Scan tool can be used to diagnose the fuel control system on fuel injected engines.
If the lower limits of Block Learn are reached, (example: 113 on 3.8L MFI) the engine is running rich for some reason and would be compared to a
"fixed above 50 degree" dwell reading on a (CCC) carbureted engine.
If the high limits (example: 150 on 3.8L MFI) are displayed the engine is running lean and can be compared to a "fixed below 10 degree" dwell for
(CCC) carbureted engines.
A Block Learn reading of 128 would be compared to a "30 degree dwell" on (CCC) carbureted engines.
As with the carbureted dwell checking procedures, the block learn should be checked at idle and 3,000 rpms.