Injectors stuck on after priming pulse
I hope to add more information to this page as the information becomes available during the week.
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 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. With the large injectors run in these cars it will quickly fill the cylinders and cause a hydro lock. Luckily they fill up quickly enough that engine damage seem to have been avoided. A significant amount of oil and time has been wasted.
One of the cars was has been running for two years and the problem was noticed when reviving the car after the winter. The other did it once right after the initial install but then would not do it again until a few days later. The problems seem a bit different on the two cars but the similarities are still striking.
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. The state of the fuel pump is not known on this car when the problem occurs.
Car2 is a Volvo 240. The problem doesn't occur when the injectors are not connected when the ignition is turned on. But when the injectors are connected during powerup they will get stuck in an on position. This car also leaves the fuel pump on forever when the problem occurs. I haven't diagonesed this problem properly yet, the customer is a skilled mechanic and found the irregularity with the disconnected injectors himself.
Trigger setup - sounds like VR signal noise (=> fuelpump on; might not explain injout though )
- please confirm it has primary trigger VR
- DC bias voltage of primary trigger ?
Planned tests:
I have come to suspect that both these cars have a double CLT sensor, which means that the sensor ground is connected to engine ground through one of the 2252 ohm NTC resistors inside the CLT sensor. I don't see how this could cause a problem but it may be a common denominator. I will see if the problems can be recreated without the sensor connected.
I will check that the ECU is not stuck in boot loader when this happens and that I can communicate with the ECU as expected when the problem occurs.
Configurations for both cars will be posted when they become available tomorrow.
- vemslog
- when something weird is thought to happen
- at least vemscfg