Wide band O2 Sensor and tuning options

I am planning to add a wide band O2 sensor, gauge and computer interface to my Volvo 142E. This will be completely independent of the D-Jet system but can be used for monitoring air fuel (AF) ratios under different conditions. Here in USA, there are a few popular sensor setups including from Innovate and AEM.

I will have everything else in 100% working condition and complete tune up, etc. Trying to play around with AF ratios when something is wrong is pointless.

I am interested to know what possible ways exists to influence the AF ratio? I am not so interested in just cranking up fuel pressure and seeking something more. For example, a popular Volvo tuning company in USA (IPD) had an 'enrichment adjuster knob' they sold.

Thanks,
Peter.

1973 Volvo B20E
California

Hi Peter,

well as you know D-Jetronic is an open-loop control system. I know of the US fashion to monitor A/F and try to tune D-Jetronic. However this is a difficult one. D-Jetronic only has one tuning possibility and that is idle-run CO. The rest is given. I know that there are people playing with fuel pressure or MAP sensor adjustment. Both are wrong places. Why? You should look at A/F ratio in all revs and all possible load states. That is not possible without a performance test stand - as was done originally by car manufacturers. Just by noticing a too rich mixture during driving in one possible state does not imply that improving this state will not also influence all other possible load and rev states of the car.

The real place to adapt would be the right function blocks in ECU. Tuners like AMG did that to improved engines. But they had a test stand to measure and try out what they had done. I sometimes discuss with people you have completely changed their engine. Bigger bore, other cam shafts etc. They might even want to run their car in rallying and prefer an A/F smaller than 14. My best recommendation in such cases are after-market catalytic control devices for D-Jetronic as they existed in the 80s. In Germany we had Gutmann and GAT selling them. They use an O2 sensor (not broad-band) and either change engine temperature sensor value or supersede MAP sensor values (similar to idle-run potentiometer). They make D-Jetronic a closed-loop control system without a catalytic converter. So my recommendation: If you want to play, play it the right way and do not just fiddle around in one corner destroying the other corners.

Hi Dr-Djet,
Wonder what is the Gutman and GAT item you were talking about. Where do I purchase one? I searched for 3 hour and found nothing.

Hi,

those products were needed in 80s when tax on cars without lambda control and catakytic system were introduced in Europe. After 40 years no one needs them any more. Most cars are gone and the few that have survived are not hit by taxes any more when they have a so called historic number plate.

If I remember exactly I have one of the GAT lambda ECUs here as new.