erik69&85

iTrader: (1)

Not so much as a question but documenting my recent experiences.... with both... and if others have had similar experiences.

Bought my 88 IROC vert LB9 2 years ago. Previous owner had replaced the MAF with a new Delphi unit. He told me it took 3 tries to get on that worked...

But the car was still having issues... mostly it would die when cold and coming to a stop. Also, getting numerous High Airflow error codes when driving. Would have to stop, shut the car off,,,wait... then restart in order to get the ECM to listen to the MAF again.... after working with the settings.. i got it to run better and not stall. Had to open up the minimum airflow on the throttle body and advance the TPS to better align with the false high airflow it was seeing with the Delphi unit not able to send the lower airflow signals.

So I recently acquired a used original BOSCH unit with the correct model number for an 88. When I just swapped them, the BOSCH unit resulted in poor, jumpy idle.. and the car felt like it lost a step... it felt and smelled rich to my TPI experienced brain. So I reset the minimum air and the TPS. That got the car back to how it should be... so much smoother.

with Delphi unit
TPS - 0.60 V
minimum air - advanced 1/2 turn

with BOSCH unit
TPS - 0.54 V
minimum air - back to base setting (1/2 turn behind Delphi unit)

Hope this helps anyone that needs to switch between the two... The Delphi unit seemed to require me to get it just right... a sweet spot.. otherwise... CODES.....

Vader

That is additional information which seems to support the idea that something has changed with the standard specifications for MAF units used by these systems originally, and it doesn't always work the same as a result. Since the beginning of 2023, and perhaps several months before, several of the group here have reported issues, some of which are possibly still not resolved.

Since the original MAF units for these were supplied by Bosch, it seems reasonable that those could be more reliable.

TTOP350

iTrader: (8)

One of my cars has picked up an odd issue of going lean in a 700rpm window at a steady speed. The light comes on, car stumbles and drops to idle unless i feather the throttle. Not sure if its the switch to the delphi maf or what yet. I have tested the tps sweep and that seems fine but haven't had time to go much farther.