bdv

Have a 1990 Integra LS 5-speed manual transmission with B18A1 engine.

Problems:

Have been having idling problems: surging/varying idle

AND

Drive ability problems: cold runs fine, but when warms up below 2500 rpm have sputtering, loss of power and backfiring. Have to get above 2500-3000 rpm to run ok and stop sputtering and backfiring which engine is warmed up.

Fixes done so far:

Checked for vacuums leaks, none found.

Removed FITV = Fast Idle Thermo Valve and tightened plastic screw.

Replaced IACV = Idle Air Control Valve

Results

Surge/varying idle fixed.

What was not fixed was the sputtering, loss of power & backfiring when the engine warms up (temp gauge about ¼ way up).


Manual says: “Lag angle is adjusted in accordance with warming up conditions…”

Possible bad Coolant temperature sensor causing ECU to adjust timing wrong?

Thanks for the help. BDV