The table below shows a selection of 4 Gas Analysis samples, taken from vehicle case studies.
They were measured using a SUN DGA 1800 analyser.
RPM | CO% | CO2% | HC ppm | O2% | Lambda | Vehicle | Condition |
---|---|---|---|---|---|---|---|
Idle | 2.84 | 13.03 | 436 | 0.50 | 0.925 | 307 TU5 (1) | Engine just started from cold, illustrating rich mixture and cold catalyst (No Fault) |
Idle | 0.00 | 15.18 | 47 | 0.06 | 1.001 | 307 TU5 (2) | As above, approximately 1 minute later (No Fault) |
Idle | 0.38 | 14.28 | 153 | 0.69 | 1.015 | 307 EW10 (1) | Engine cold, catalyst not warmed up (No Fault) |
Idle | 0.00 | 15.12 | 0 | 0.00 | 1.000 | 307 EW10 (2) | As above, engine hot (No Fault) |
Idle | 0.00 | 14.08 | 0 | 1.46 | 1.073 | 806 EW10 | Injector misfire |
Idle | 3.47 | 12.83 | 269 | 0.03 | 0.896 | 306 TU5 | Forced Rich mixture, ECT High resistance & O2 sensor O/C |
Idle | 0.00 | 11.89 | 49 | 4.51 | 1.263 | 306 TU5 | Forced Rich mixture, ECT High resistance & O2 sensor O/C plus Injection misfire |
Idle | 3.30 | 5.50 | 2232 | 9.77 | O/L | 106 TU1 (1) | Massive air leak at the inlet manifold, caused by brake servo hose disconnected |
Idle | 0.38 | 14.29 | 168 | 0.60 | 1.011 | 106 TU1 (2) | After repair of above fault, the catalyst is shown to be inefficient |
Idle | 0.96 | 13.18 | 307 | 1.78 | 1.045 | 306 XU7JP4 | Vehicle is equipped with a motor factors replacement catalyst. The catalyst is shown to be inefficient |
Idle | 0.50 | 14.82 | 1591 | 0.06 | 0.931 | 205 XU5M | Hot engine with induced ignition misfire.(Plug lead disconnected). Unsure why the oxygen value is so low, I presume due to the catalyst action. |
2000 RPM | 0.05 | 15.16 | 67 | 0.06 | 0.998 | 605 xu10 j4 auto 1 | Hot engine, vehicle suffering from sluggish response and lack of power. Sharp acceleration created 1.5bar back pressure at catalyst. |
2000 RPM | 0.00 | 15.35 | 6 | 0.01 | 1.000 | 605 xu10 j4 auto 2 | Hot engine, new catalyst fitted. Vehicle returned to normal performance. |
Idle | 0.00 | 14.30 | 2 | 1.06 | 1.052 | 806 xu10 j2 High mileage (1) | Hot engine, partial engine misfire evident. Note the following; especially cylinder No 4. |
Idle | 0.00 | 12.96 | 14 | 2.83 | 1.153 | 806 xu10 j2 High mileage (2) | Hot engine. Cylinder No. 4 injector disconnected |
Idle | 0.00 | 12.05 | 17 | 4.02 | 1.233 | 806 xu10 j2 High mileage (3) | Hot engine. Cylinder No. 3 injector disconnected. |
Idle | 0.00 | 12.02 | 14 | 4.15 | 1.242 | 806 xu10 j2 High mileage (4) | Hot engine. Cylinder No. 2 injector disconnected. |
Idle | 0.00 | 12.14 | 16 | 4.01 | 1.232 | 806 xu10 j2 High mileage (5) | Hot engine. Cylinder No. 1 injector disconnected. |
Idle | 0.51 | 13.22 | 116 | 1.77 | 1.069 | 106 GTI (NFX)-(1) | Hot engine, MOT failure. New catalyst had been fitted. Not genuine and cheap!! |
2000 | 0.67 | 13.52 | 147 | 1.39 | 1.041 | 106 GTI (NFX)-(2) | As above, hot engine, MOT failure. New catalyst had been fitted. Not genuine and cheap!! |
Last Reviewed: 16 April 2021Copyright © 2004...2021 Mark Stammers