Have 98 v70 2.4l auto 110k miles and only get 21 mpg surburban / Intrstate, very little traffic stop and go. Have Actron attached. No errors. Plugs and air cleaner reciently replaced. Noticed that long term fuel trim reads -8.0 to 10.0%; o2 sensor #2 v. 0.00 (sensor 1 varies .1-.7); ignition advance seldom goes above 24.5 deg. Anything look abnormal or suggestions?

 

Put the Actron tool on my 350z for comparison. Ignition advance on Z is at 40 deg as often as the v70 is at 24 deg. Any ideas as to why so little advance on my volvo?

 

Ignition timing on a Volvo is carried out by the ECU and cannot be adjusted as in the 'old days'. The 2.3 litre engine is............I believe...........6 degrees BTDC.

r.

 

Timing varies at idle between 3.5, 5.0 and 6.x degrees as if the computer is adjusting timing to control idle speed which alternates from 840 and 870 as i recall.

The Actron analizer only checks the universal OBII codes and not any that my be unique to Volvo. Are defect codes set in the computer that only Volvo tools can read? Codes that may indicate sensor or other conditions that or out of range but not significant to turn on the check engine lite?