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| I have two 4 cylinder cars which has developed similar symtoms. Both have Volvo 4 cylinder red engines, both run 1.2.31 firmware, Bosch Motorsport waste fire coil, 60-2 VR trigger. One of the cars did it first with 1.2.20 firmware but continued doing it after upgrading to 1.2.31. The problem manifests itself by leaving one or more injectors on when the ignition is turned on.Everything indicate that all injectors are left on, the only indication that two of the four injectors were left on was caused by injectors that were stuck in a closed position after not being used for a long time. A light tap with the back of a screwdriver brought them back to life. |
| I have two 4 cylinder cars which has developed similar symtoms. Both have Volvo 4 cylinder red engines, both run 1.2.31 firmware, Bosch Motorsport waste fire coil, 60-2 VR trigger. One of the cars did it first with 1.2.20 firmware but continued doing it after upgrading to 1.2.31. The problem manifests itself by leaving one or more injectors on when the ignition is turned on. |
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Car1 will NOT do it when tested on the bench, or when the prime pulse is not used. This has been a successful workaround. It will also NOT do it when the trigger sensor is disconnected, which probably explain why it doesn't do it on the bench. After reviewing the config and checking that no check valve was present in the fuel system we now know that the fuelpump kept running on this car as well. An injector output is used for the fuel pump relay. |
| Car1 will NOT do it when tested on the bench, or when the prime pulse is not used. This has been a successful workaround. It will also NOT do it when the trigger sensor is disconnected, which probably explain why it doesn't do it on the bench. An injector output is used for the fuel pump relay. |
| * this is the key... Very clear indication that it's a HW artifact caused by the injector current (not some firmware cli problem, or similar which does NOT know about the injector currents). It seems very likely that GND5 jumps above 1V (maybe >2V ?) during the priming pulse when injector currents add up.. Make very strong ground (eg. 5 x 1.23mm2 wires connected 12cm from EC36 receptacles), and if necessary, connect grounds inside ECU (and if it's VR sensor, maybe get a dedicated gnd wire for the VR sensor, from a mainboard GND pad, near the LM1815). |
| * this is the key... Very clear indication that it's a HW artifact caused by the injector current. It seems very likely that GND5 jumps above 1V (maybe >2V ?) during the priming pulse when injector currents add up.. Make very strong ground (eg. 5 x 1.23mm2 wires connected 12cm from EC36 receptacles), and if necessary, connect grounds inside ECU (and if it's VR sensor, maybe get a dedicated gnd wire for the VR sensor, from a mainboard GND pad, near the LM1815.I don't think that the problem is found there, the 5X1mm2 grounding has worked on cars with five times the GND5 current. But it's simple to make an internal ground connection to be sure. I think that the actual ground point on the chassi is in an unsuitable location, causing the ECU to reset, it's common to see very strange ground potential problems in Volvos. |
| As the fuel pump relay is driven from different output groups I think that we can concentrate on other things then the injector outputs themself => yes, eg. concentrate on grounds ! |
| ** good idea, but it cannot. |
| ** good idea, but it cannot. Thanks for confirming this. |