amcmills I've got an LH2.4 Volvo 240 that's running so rich it often won't start. I think the ECU is faulty because it messes with the signal from the ECT (engine coolant temperature sensor). With the harness disconnected from the ECU the reading for a cold engine is approx 4K-ohm. The same reading with the harness plugged into the ECU is now over 10M-ohm. Can anyone please confirm if this is normal or is my ecu broken? Thanks Other Info: New plugs, leads, cap and rotor. Coil is good but came off lh2.2 volvo 240 (is there a difference?) Ignition module replaced a couple of years back New ECT sensor New Bosch oxygen sensor fuses and relays seem ok. Good compression No major air leaks Fuel pressure around 15% too high (probaly due to salvaged Commodore pump in-tank) Found some corrosion on the pins in the ECU connector but I cleaned them up and they pass a continuity check.
carnut222 Where are you measuring the sensor resistance? In case one I assume you unplugged the loom and are measuring 4K-ohm at the sensor between the 2 terminals. In case 2, technically I believe the manual states to back-probe the appropriate connections at the ECU (don’t stick the probes into the ECU connector, but instead remove the plastic cover and back-probe from the wire side (otherwise they state you can damage the connector). With LH2.4, one sensor terminal should go to ground (earth) and the other to the ECU, IIRC. I have the Bentley manual and also green books out in my shed. If you want I can give you specifics on the terminals to probe, resistance values, whether or not to do it with the ECU connected, etc. Lemme know. Greg
Kaziganth https://ufile.io/huerq I uploaded the LH 2.4 fault tracing manual I have on my pc. I hope you'll find it useful.