My 172 Cup is starting to play up. Symptoms are misfire/judder at low rpm and high loads. Think around the 1400-2200rpm area and a decent amount of throttle. Has a bit of a miss when pulling away occasionally too. But most noticeable in 4th and 5th gear.
Idle is steady and as smooth as one of these can be really. So pulling injector leads off isn't going to narrow it down.
Pulls and sounds fine especially over 3000rpm.
I've so far ruled out the ignition coil as I've tried a known working one and it had no effect.
Resistance measurements through the injectors are all around 15ohms.
No1 HT lead has 3094ohms resistance
No2 HT lead has 2235ohms
No3 HT lead has 1778ohms
No4 HT lead has 2133ohms
Spray patterns on the injectors and volumes look to be equal too.
Unplugging the MAP sensor makes no difference.
Did have a fault code and EML on for pre-cat lambda probe. This came on a while after the hesitation started.
I've since switched the pre and post lambdas around. EML hasn't come back on but there is a code logged for the post-cat lambda (the old pre-cat).
When the engine is misfiring there's no EML at all. Not flashing or constantly on. Only code stored in the ECU is the post-cat lambda heater circuit.
Can anyone tell me if those resistance readings are about right? And what else should I be looking at? I've only got Torque lite app and a basic Bluetooth type dongle and a multimeter.
Idle is steady and as smooth as one of these can be really. So pulling injector leads off isn't going to narrow it down.
Pulls and sounds fine especially over 3000rpm.
I've so far ruled out the ignition coil as I've tried a known working one and it had no effect.
Resistance measurements through the injectors are all around 15ohms.
No1 HT lead has 3094ohms resistance
No2 HT lead has 2235ohms
No3 HT lead has 1778ohms
No4 HT lead has 2133ohms
Spray patterns on the injectors and volumes look to be equal too.
Unplugging the MAP sensor makes no difference.
Did have a fault code and EML on for pre-cat lambda probe. This came on a while after the hesitation started.
I've since switched the pre and post lambdas around. EML hasn't come back on but there is a code logged for the post-cat lambda (the old pre-cat).
When the engine is misfiring there's no EML at all. Not flashing or constantly on. Only code stored in the ECU is the post-cat lambda heater circuit.
Can anyone tell me if those resistance readings are about right? And what else should I be looking at? I've only got Torque lite app and a basic Bluetooth type dongle and a multimeter.
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