Clio 172 ph2 not starting

[Blackdavid]

Hello.
Ran into some gremlins a couple of days ago.
Car was running on idle for about 10 mins while i ran some diagnostic software just for the sake of it.
I notices the rev gauge was a bit weird as it jumped from 500-2000-1000 etc, while the car was idling fine and running great.
I shut it off, and after about 10 mins went to start it again, cranking but not starting.
After some tries, it cranks for a couple of secs then stops.
Fuel pump isn't priming, no power at the pump. Got it out and checked on a battery, works fine.
I'm assuming no power at the coil either.
Relays work, tried swapping them around, fuses are good.
Could this be caused by the immobiliser? The red light is not coming on or blinking, basically dead, but since i got the car recently i didn't pay attention if it was working ever.

 

[Touring_Rob]

Hello.
Ran into some gremlins a couple of days ago.
Car was running on idle for about 10 mins while i ran some diagnostic software just for the sake of it.
I notices the rev gauge was a bit weird as it jumped from 500-2000-1000 etc, while the car was idling fine and running great.
I shut it off, and after about 10 mins went to start it again, cranking but not starting.
After some tries, it cranks for a couple of secs then stops.
Fuel pump isn't priming, no power at the pump. Got it out and checked on a battery, works fine.
I'm assuming no power at the coil either.
Relays work, tried swapping them around, fuses are good.
Could this be caused by the immobiliser? The red light is not coming on or blinking, basically dead, but since i got the car recently i didn't pay attention if it was working ever.

Normally I would say pull the fuse box out and take a look at the white connector underneath. Usually this corrodes and causes immobiliser issues - it certainly did on mine. Cleaning the contacts and putting it all back together worked.

But the gauge cluster mucking about is odd. I'm fairly sure when the immobiliser light should be solid on when the car is immobilised so that's another odd bit.

Perhaps start off with the white connector anyway as its quick, 30mins and rules that out.

 

[Blackdavid]

Normally I would say pull the fuse box out and take a look at the white connector underneath. Usually this corrodes and causes immobiliser issues - it certainly did on mine. Cleaning the contacts and putting it all back together worked.

But the gauge cluster mucking about is odd. I'm fairly sure when the immobiliser light should be solid on when the car is immobilised so that's another odd bit.

Perhaps start off with the white connector anyway as its quick, 30mins and rules that out.

I've already checked the connector, looks fine so didn't do much. Just a quick contact spray on it.
The cluster playing led me to believe the crank sensor is done, but changed it and the connector today and still no luck.
Also, the live data from the diag shows 0 rpm while cranking ( with the new sensor, and the old one) so i'm assuming there is something wrong with the ECU?
A new coolant temp sensor also didn't change the data that stated the coolant was -40°C, and the fans turn on at max when i plug their relay back and turn the key to acc.

 

[Blackdavid]

Also, diagnostics gives me a couple of codes that i can't quite relate, that leads me to to ecu again;

-throttle potentiometer ( intermittent)
- +30 voltage ( intermittent)
- throttle control valve ( present)
Codes can't be cleared, sometimes it gives a couple more but can't remember which ones.

 

[Blackdavid]

UPDATE: got the UCH checked, loose solder on all three connections, fixed a couple problems, it now reads rpm, but still no start.
Also, now i can crank it without pressing the button. Anyone?

 

[Blackdavid]

Any help?

 

[hopgop1]

If it's still doing the same as in the OP, as in "it cranks for a couple of secs then stops.", the immobiliser is active, that's where I'd start looking.

 

[Blackdavid]

Just sometimes. No rule really, sometimes it cranks for how ever long i hold the key, sometimes it cuts out after a couple of secs.