General Bravo intermittent starting fault

[Nigmyk]

I have a 1999 Bravo SX which is showing an intermittent starting fault when the engine turns over but doesn't fire. This occurred more in the winter when it was damp and on one occasion the AA mechanic I called out got it going after cleaning out and drying some electrical connectors at the lower front of the engine. (sensor cable?) I even got it going myself one damp day by blowing a hairdryer on the cable connectors. However, it sometimes happens on warm dry days and nothing except leaving it (and charging the battery which inevitably gets run down trying to start it) seems to get it going again. Any ideas what exactly is going on and what I can do to get rid of this fault completely for ever? Thanking you in anticipation.

 

[Deckchair5]

That sounds like your rpm/crank sensor as that will give you no starting at all one moment and then act as if nothing has happened the next. That's also at the lower front driver's side of the engine




Check the connector, spray some contact cleaner (avail Halfords £4 a tin) on it, check air gap betweenm the sensor and the flywheel pulley "teeth", check the sensor for resistance.

It's a bit of a sod when it's intermittent though

 

[jug]

:yeahthat:

 

[Nigmyk]

Thanks for that. What does the crank sensor do? Can't recall any of my other cars having one. What does it detect and why does it stop the engine from starting?

 

[jug]

it tells the ecu what position the crankshaft is at, and what the speed of rotation is (rpm), which is critical for ignition timing. no signal means no sparks, and if your sparkplugs arent sparking it will never start.

cars that use a distributor do not need a crank sensor, so i guess you've previously owned older cars.