Technical Multipla won't start - help

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Technical Multipla won't start - help

thunderbug52

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Feb 24, 2019
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FiatMultipla 1.9JTD 120HP 2008
Help
So itseamed like a good idea to buy a Fiat Multipla that wouldn’t start as a bit ofa project and hopefully get a cheap car out of it. I am now running out of ideas. I have had a good look around the forum andgoogle but need some more help.
The carturns over but won’t start. On occasionit sounds like it tries to fire.
So far Ihave done, and know the following
Battery isgood, starter is good.
No faultsin the fault log
Glow pluglight comes on and goes out after a couple of second as it should
Immobiliserlight comes on and goes out as it should
Replace thecrankshaft sensor
Tested thecamshaft sensor – following the guide on here
Tested thelow pressure fuel pump all good
I can hearthe injector pump prime before I turn the engine over.
Using theOBD2 I can see a fuel rail pressure on around 45000-50000 kpa when cranking theengine. I believe this to be good.
Using a multimeterI have checked the voltages at the injectors, I believe this to be good butwill make up a lead with some lights to visually watch them operate.
Using theODB2 I have monitored the MAF reading when cranked. This reads 1 G/S. Is this a bit low?
I have alsotried easy start spray but this has no affect.
Any furthersuggestions are welcome.
Thanks
 
My current thoughts are that the engine may not be getting enough air to fire, hence why the easy start is having no effect.


I will check the glow plugs and see if I can start it on a tow.


Thanks
 
Perhaps someone on here can measure their MAF reading during cranking and give you some feedback?
It doesn't take too much effort to remove the airbox, duct to the compressor inlet and duct from the intercooler outlet to the intake manifold. This way you can have a little spin of the turbo and jugde whether it's in good order and also potentially check the function of the throttle valve that's just infront of the egr valve. I think it's vacuum operated - hopefully normally open - but if its closed during cranking then it'll never start.
Otherwise as you say the rail pressure looks good.
I dont think a blocked DPF could stop it starting but does the telltale light on the dash go out?
Finally how taking off the oil filler cap and checking that the cam is moving as it's being cranked.

Good luck!
 
Some good suggestions, I will have a go once I finish work for the day and report back.


Thanks
 
I found some data!:slayer:

I took this recording on my '03 115 jtd so quite possibly different to your 120 multijet. Nevertheless, the airmass at just under 500rpm is 188mg/stroke, then settles out at 420mg/stroke during the 900rpm idle. Your idle airmass might be lower as for some reason my car didn't run egr for some period after start(considered a defeat device now).
The value of 3276.7 before the start is a default value when the MAF isn't seeing a sensible reading.
 

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So I’ve had a quick play, didn’t get time to get all the way down to the turbo and no one else around so couldn’t try a tow start.

I did get to the throttle valve which is very mucky, more than I expected. I have attached a photo.

Although mucky it still operates (it electric and moves fully open/closed when the key is turned (not cranked).

Although I didn’t get to the turbo, I get a good flow of air from the air intake to the throttle valve pipe, so no apparent blockages in the turbo/intercooler.

Hopefully I will get some more time tomorrow and will get to the turbo and have a look past the throttle valve/erg for blockages.

Thanks
 

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Yes, the cam is turning.
I am using am icarsoft error code reader. It’s only got basic odb2 functionality for the fiat as it was bought for a Renault.
 
Good news!!!
It turns out it was a blocked DPF, although the light on the dash suggested it was good.
Not sure what that dash light is supposed to do, on mine it doesn't change regardless of the state of the DPF. And I have had a blocked DPF. It does come on with the ignition before starting indicating the light itself works, but then it always goes out.
 
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