Clio 172 injectors HELP Please

[Shaun 172]

Hi guy's got a problem with my phase 2 172
it wont starts it cranks over fine it has got a good spark theres fuel upto the injector rail but i dont think the injectors are pulsing. What controls the injectors to pulse? Faulty ecu?
Any help will be greatly recieved thank's

 

[Fred@BTM]

crank sensor

 

[Shaun 172]

Its had a new crank sensor with the updated plug aswell
I thought the crank sensor only controls the spark ??

 

[Fred@BTM]

nope, controls the fuel too

 

[Shaun 172]

Right just let me get this straight the crank sensor controls the injectors aswell as the spark? I would have thought that if the crank sensor had gone down i would lose both spark and fuel not just one.

 

[Cup_Phil]

Is the immobiliser light on by any chance?

I bow to Fred's superior knowledge but I'm 90% sure that if the crank sensor is dead you wouldn't be getting a spark either.

 

[Fred@BTM]

injectors aren't firing, but spark plugs are?? (sorry didn't read the entire thing there!)

yes crank sensor sends signal to ecu so it know when to fire what

what are the lights on the dash doing? give the small relays in the engine fuse box a wiggle

 

[Shaun 172]

Yep immobiliser light goes out and stays out whilst cranking so i dont reakon its an immobiliser fault but the abs and service light start flashing when you've been cranking over for a couple of seconds. @Fred tried that one with the relays also checked the fuses in both the car and engine bay and all ok

 

[Cup_Phil]

It's gotta be a knackered relay or fuse

 

[Fred@BTM]

or the main braided earth, throttle body buzzing yeah?

 

[Shaun 172]

Checked all fuses with a continuity tester all good.
@Fred main braided earth all good just checked and no buzzing from the throttle body

 

[Fred@BTM]

no noise from throttle body means a relay has gone down normally

 

[Shaun 172]

Cheers Fred I presume it'll be one of the little brown ones in the engine bay fuse box?? I've commondeered our lasses 172 cup for tomorrow so im gonna swap the relays one at a time and see if it will fire up.

 

[franx]

My TB has been buzzing for as long as i can remember ? Or at least something is buzzing under the hood... coming from the throttle body area

 

[Shaun 172]

Finally got to the bottom of this problem last week after a lot of testing I found a broken wire in the main engine wiring harness between the ignition relay and ecu. In Renaults wisdom they made this wire too long in the loom and looped it back on itself and the break was in the loom so I cut out the broken section and rejoined the wire and all is good again the car fires up 1st time everytime so im a happy bunny again