Nicke Nymans Volvo 242
News
2007-08-22
Started up tonight and got it running on all cylinders but the last in the ignition table, we moved the cam sync around but the problem still remained on the last cylinder despite moving it so that we had to re-arrange the ignition output table. See more info below.
Engine specifications
- Volvo B21ET
- 4 cyl, OHC, 2 valves/cyl
- Stock B21ET bottom end
- Volvo V cam (279 degrees @ 0.51 mm, 11.37 mm valve lift)
- Custom intake plenum and 65 mm throttlebody
- Low impedance 900 cc/min injectors used with 6.8Ohm/50W resistors and a30 V TS diode on the flyback wire
- COPs from an Audi S4
- Long tubular turbo exhaust manifold
- Holset HX35 turbo, 55 in/60 out with 12 cm² exhaust housing.
- Large front mount intercooler
- Primary trigger consists of two metal points for simple trigger using Honeywell GT1 Hall-sensor, signal goes low 60 degrees before TDC.
- Secondary trigger is a lobe on the balance axel found in these engines, same rotational speed as the cam. Signal goes low after cyl 4 TDC and high again before TDC + 90 deg.
- The lobe was originally made for driving a mechanical pump
- The lobe has been shaped to be 10 mm wide and ends abruptly to get a good metal piece for the sensor
Trouble
This engine runs separate coils which seems to work great, only I can't get the last cylinder in the ignition order to fire. We have adjusted the secondary trigger event both forward and backward and tested different ignition orders in the process, but the last ignition output in the table doesn't fire.
- We are running firmware 1.0.73
At the moment the cam sync signal will go low after TDC for cyl 4 and will have gone high again before cyl 4 TDC + 90 degrees. It should not race with the primary trigger event nor the ignition event at all. As the cam sync active edge (falling with the GT1) appears after the coil has been fired in the previous ignition event, we should be ok (with margin to spare).
- Can we use the trigger log to diagnose this?
- Is the information on any of the LCD display pages of any use to reveal the problem?
- Is a firmware upgrade to 1.1.x the way to go ?
Related info is found here : GenBoard/Manual/InputTriggerCamSync
Pictures
