1.9jtd Doblo cranks but won’t start, tried everything

[Seagullrestorer]

My mk1 fiat doblo 1.9jtd won’t start, well actually once in a while it will start and run perfectly but then goes back to not starting just cranking
No errors apart from glow plugs
So far crank sensor changed
Cam sensor changed
Fuel pressure rail pressure fine
Timing belt correct position and fine
Swapped over relays like for like etc no change
Battery voltage fine
Disconnected maf and won’t start still. Then reconnected
Egr blanked off
Fuel pump fine and good flow through the filter

I don’t understand why on the odd occasion it does start it starts instantly, help I’ve run out of ideas

 

[varesecrazy]

Are you reliably getting power to the glowplugs..?

The error covers the whole circuit.. not just 4 x 'bolts that glow'

 

[Seagullrestorer]

Thanks for the reply, I thought glow plugs weren’t needed to start the engine apart from in really cold weather but I’m no expert on diesels

 

[Seagullrestorer]

Tested glow plugs and 2 are dead, would this cause it not to start? It fires sometimes but won’t start at all now

 

[jackwhoo]

Is the anti shudder valve sticking shut and so not allowing any air into engine ?

Will engine fire if you squirt easy start / brake cleaner into inlet air after air filter?

I wonder if it could be an imobiliser issue , engine will crank but not fire if chip in key not "seen" or "recognised". If you have multi ecu scan do you have any starts blocked by imobiliser or words like that?

I have couple or more glow plugs failed on my 1.9jtd 2003 and it does still start Ok.

 

[jackwhoo]

Try jump lead from battery -ve to engine metal and another jump lead from engine to chassis

 

[varesecrazy]

Tested glow plugs and 2 are dead, would this cause it not to start? It fires sometimes but won’t start at all now

I asked if they are getting power..

A bad relay will mean NO GLOW

 

[Seagullrestorer]

HI

Checked the relay and gives voltage for a short time after I turn the ignition on ( enough time for me to walk out the drivers seat and use a multimeter and then clicks off)

Will check the other things you’ve mentioned when the rain stops lashing down and get back

 

[Seagullrestorer]

I think I’m getting somewhere, my scanner is now saying timing revs synchronisation no signal... unsure why because ive replaced the crank sensor trying to solve the issue and I’ve changed the cam sensor too BUT the cam sensor was worryingly cheap compared to what they usually are at £9.50 made by HAAS maybe I’ve changed a faulty one with a new faulty one?

 

[Seagullrestorer]

Well well well the cheap cam shaft sensor was to blame, lesson learned don’t buy HASS cam shaft sensors, buy Bosch even though they are £65 more

 

[varesecrazy]

This turned out to be mechanical interference damaging the sensors..

Link here:
https://www.fiatforum.com/lets-talk-fiat/485083-camshaft-sensors-keep-blowing-2.html?p=4576130