Thread: Misfire
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Old 14th May 2014, 10:30 PM
Davidbolam Davidbolam is offline
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Join Date: Mar 2011
Location: Gosforth, Newcastle Upon Tyne
Posts: 856
Default Misfire

Is anyone an expert with mx5 engine.

My car idles fine but as soon as I touch the throttle the engine revs drop. This is the point where the throttle position sensor switches in. (I got my multimeter out to check). The engine misfires throughout the rev range and seems to be getting worse.

I have changed the coil and the ht leads.

The engine seems to be running rich as my plugs have black deposits on them and I've got the same in the exhaust. (Powdery deposits so not oil)

Has anyone got any ideas. I have checked everything I can think of apart from the temp sensor for the ecu which I will do next. I have also tried unplugging the lambda sensor but this didn't make any difference.

David
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Saturn MX5 Based Chassis, Limited Slip Diff & 2.4 Quick Rack.

Build cost.... seems to be spending more on tools than car bits at the moment! (they will be handy in the future though).
Car iva'd and passed 15/08/2014. Finished weight 572kg.
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