Have been asked to check this by another garage on Friday. So far I'm stumped. Will try to run closed loop when first started but after a noticable change in engine note, it gives and goes open loop.Tested so far -
CO 0% HC 0
CO2 7.60% 02 10.35%
Lambda 1.96
Manfold vac 9 in Mg
Fuel pressure 2.6 bar with vac on (what there is of it!)
Data taken at 900 RPM showing open loop figures in brackets
TPS 0.93 Coolant 82 deg C
MAF 3.32 g/s (1.66)
Maf volts 1.13 (0.54)
02 10 mV but does switch when rev'd
inj duration 6.4 m/s (4.5)
No back pressure in exhaust, blocked off servo take off and EVAC pipes, checked for air leaks. Compressions all good at around 180 PSI.
Its obviously got very low manifold vacuum and I assume thats why its not burning much fuel even with apparently high injector duration. I can find no reason for this low vacuum though!
Its doesn't appear to have an EGR system on this engine. (I may not be looking hard enough though)
Any ideas?