Technical All's well with the World - then .......................

[Factseeker]

Fiat Doblo 2005 Diesel MPV1.9 JTD Active.​

Hi All,

Purchased early April to use as a runabout.

Solved a final problem ref Smoking Exhaust with a replacement MAF - now very clean running - considerable increase fuel economy - now circa 43 miles / gallon = 9.45 miles/ltre.

All was 'well with world' - ready for winter - then this morning - no start up.

MultiScan - shows Fault - Preheating Control Unit ( feedback) - 'low signal' - see Attachment Image 'NO START 1'

eLearn not showing much for that sort of thing.

Engine Started OK using squirt of EasyStart into Air Inlet System - first time I ever used - however product description states >>

"Warning: Diesel and petrol start must not be used for diesel engines with preheater" - 1st Question does the Doblo have preheater?

I have found images ref Heater Plugs and their placement on Doblo Engine - but as MultiScan states problem is a 'low signal' - see Attachment - can that be caused by Faulty Heater Plug/s or better to first look at wiring and connections?

Engine starts just fine now warm - just as always previously.

This morning was cold - but certainly previously colder mornings - however it was extremely wet/damp.

The Car has been a real 'winner' so far - especially since MAF incident - so wish to persevere.

Any advice more than welcome.

Best Rgds.
Steve

 

[cris1117]

First thing I would check is power going to the glow plugs at the correct time, I think the control unit for the glow plugs can play up on these engines.

 

[jackwhoo]

For your engine preheater =glow plugs

 

[Factseeker]

First thing I would check is power going to the glow plugs at the correct time, I think the control unit for the glow plugs can play up on these engines.

Hi Cris,

Just looking at that this morning - as Multiscan detailed 'not displayed' on Dash Display - wondered if a clue for that.

Have you any dea where it is situated.

Best Rgds.
Steve

 

[Factseeker]

For your engine preheater =glow plugs

Hi,

Yes understand - the whole world seems to be afraid of extracting the glo plugs - certainly reading about it has worried me. ;o))

Of course they are sited right behind and below the inlet manifold by look of it.

But where is that control unit - any ideas where to start the search?

Best Rgds

 

[cris1117]

Sorry haven't worked on this particular engine, its a small black plastic box usually on the bulkhead.

If you google it you will get some pictures so you will know what it looks like.

Firstly I would use a circuit tester on the glow plugs to see if they have power, remember they may only be powered for the first few seconds when you turn the ignition on.

If as I suspect they aren't, then if the control box has incoming power but no outgoing power then you will need to check all earth points if o.k then I would suspect a dead control unit.

 

[Factseeker]

Sorry haven't worked on this particular engine, its a small black plastic box usually on the bulkhead.

If you google it you will get some pictures so you will know what it looks like.

Firstly I would use a circuit tester on the glow plugs to see if they have power, remember they may only be powered for the first few seconds when you turn the ignition on.

If as I suspect they aren't, then if the control box has incoming power but no outgoing power then you will need to check all earth points if o.k then I would suspect a dead control unit.

Hi Cris,

Just got back from checking - you are right - Control Unit on bulkhead - I recognised it from an eBay image.

So all good to do some testing with trusty multi meter - I did research all checking that can be done to the plugs yesterday - so ready to go see.

Thnxs so much for input - I will let you know how things go.

Best Rgds.
Steve

 

[Factseeker]

Sorry haven't worked on this particular engine, its a small black plastic box usually on the bulkhead.

If you google it you will get some pictures so you will know what it looks like.

Firstly I would use a circuit tester on the glow plugs to see if they have power, remember they may only be powered for the first few seconds when you turn the ignition on.

If as I suspect they aren't, then if the control box has incoming power but no outgoing power then you will need to check all earth points if o.k then I would suspect a dead control unit.

Looks like no power to Control Unit - tested it using engine as Earth and also Neg Battery Terminal as Earth - nothing at the big red cable affixed at the Control Unit with ignition ON to point of Dash Display.

So now to research if a Relay or Fuse for power to Control Unit

Thnxs for all - on with the 'motley'.

 

[Factseeker]

Sorry haven't worked on this particular engine, its a small black plastic box usually on the bulkhead.

If you google it you will get some pictures so you will know what it looks like.

Firstly I would use a circuit tester on the glow plugs to see if they have power, remember they may only be powered for the first few seconds when you turn the ignition on.

If as I suspect they aren't, then if the control box has incoming power but no outgoing power then you will need to check all earth points if o.k then I would suspect a dead control unit.

Hi Cris,

Just a big thankyou for 'nudging' me in the right direction - the problem??

A big ol' Red 50A fuse which sits in the Engine Bay Fuse Box casing - thus no power to the control box at all.

New fuses underway - 5 just in case - should arrive tomorrow - only question now - what caused the fuse to blow??

Could a 'dodgy' Glo Plug cause that - maybe shorting or whatever??

No indication of trouble - shut engine off 3 nights ago - then NoGo the next morning.

Best Rgds

 

[cris1117]

Glad to help.
I would have a quick look at the connected wiring just to make sure its not rubbing on anything if it looks o.k and you're buying a few fuses I would just try one if it blows then you may have a short.

 

[The Panda Nut]

Look for an electronics repair specialist as the control box is probably repairable if its at fault. Fuse blown would most ;ikely be caused by a dying glow plug. Always replace in sets. or you may have to go back time after time. Very pleased to read you seem to have resolved all your issues. It hopefully will go for a long time. I once looked at a Bravo with a similar engine and it had 265,000 on the clock and was still sounding good.

 

[Factseeker]

Glad to help.
I would have a quick look at the connected wiring just to make sure its not rubbing on anything if it looks o.k and you're buying a few fuses I would just try one if it blows then you may have a short.

Hi Cris,

Yes exactly what I figure to do - bit worried ref Glo Plugs - practically invisible under what I presume is Inlet Manifold -all wiring I can see looks really 'healthy' - so praying more centered on Control Box if another Fuse pops.

 

[Factseeker]

Look for an electronics repair specialist as the control box is probably repairable if its at fault. Fuse blown would most ;ikely be caused by a dying glow plug. Always replace in sets. or you may have to go back time after time. Very pleased to read you seem to have resolved all your issues. It hopefully will go for a long time. I once looked at a Bravo with a similar engine and it had 265,000 on the clock and was still sounding good.

Hi Panda,
Thnxs for comment.

" Fuse blown would most likely be caused by a dying glow plug." Yep that is what worries me.

Glo Plugs - never mind to extract - difficult to even see them - practically invisible under what I presume is Manifold - all wiring I can see looks really 'healthy' - so praying more centered on Control Box if another Fuse pops.

Best Rgds

 

[cris1117]

A long time since I worked on diesels, if you have a multi meter you can test each glow plug individually, if one is faulty and blowing the fuse just unplug it and see if motor is happy on three.
Removing glow plugs can be a nightmare when you can see them, so hidden ones would be very problematic and expensive if one snaps off in the head.

 

[The Panda Nut]

Only ever had one set canged. Done at a Bosch diesel centre while I waited. Labour cost was minimal. I think they use induction coil heater before undoing. The right equipment seems critical. Alas its the most likely thing.

 

[Factseeker]

A long time since I worked on diesels, if you have a multi meter you can test each glow plug individually, if one is faulty and blowing the fuse just unplug it and see if motor is happy on three.
Removing glow plugs can be a nightmare when you can see them, so hidden ones would be very problematic and expensive if one snaps off in the head.

Only saving grace is that the Car starts very well indeed and at the moment literally the minutest puff of Easy Start into the airfilter box and we are off - rest of day no need for anything.

I took some time this afternnon and think I have now spotted them - - down through he arches of the inlet manifold - at least just the top cabling into what I assume is the top of the Connector down onto the Plug - I cannot even be sure of the type of Connector used to disconnect - no wish to damage those.
If I am right looks like a nightmare - cannot believe but think I am right based on a Youtube of a chap doing this work ( he managed OK ).

If this was Summer - I would in fact look at taking off the inlet manifold and really clear the way.
But at this time of year - no thankyou.

I cannot even get a multi meter prob in there to touch - so that I can check Ohms.

So my work will be restricted to checking the Relay out and if it is not that - off to garage.

Thnxs everyone for all the input.
Now to a problem i finding correct Relay.
Best Rgds

 

[Factseeker]

Only ever had one set canged. Done at a Bosch diesel centre while I waited. Labour cost was minimal. I think they use induction coil heater before undoing. The right equipment seems critical. Alas its the most likely thing.

I am placing my hopes on dodgy Relay - just tested the old - took off the car this afternoon.
Strange signal from terminals - trying to find circuit diagram.
"they use induction coil heater before undoing" - right tools and right skills - same for any job.

Thnxs reply.