Carisma 1.9 Diesel 2002. Lack of power - Fixed!

[Angus]

Geo

It's a strong indication.  You could measure the signal voltage at the MAF.

I'd expect a good 4 volts when revved.

[Geo]

I think I might take a trip to my friendly local scrapyard and borrow one to check

[davy crockett]

Just looked up some job card notes from a trafic 1.9dci I did couple of months ago.

Symtoms were:  very flat/gutless. WOT in workshop it took over 5 seconds to build revs to 4000rpm.  This was a MAF fault.

Faulty MAF figures were:
idle 1.85v, 
WOT 3.65v


New MAF ( WOT test now only takes 2 seconds to build to 4200rpm)
idle 2.00v
WOT 4.25v

Obviously you need to make sure there is nothing else restricting air flow, but I'd say its very likely to be MAF. 

Dave

[Geo]

Great info Dave, thanks very much 

[davy crockett]

Beats trudging around a scrapyard!

[Geo]

Ok here we go:

Idle: 2.00V
WOT @4000RPM: 3.85V

Now that was the first WOT test. On subsequent attempts the engine won't rev past 3200 or so.

Voltage at a constant 3000RPM: 3.05V

[Angus]

Geo

Unless it's got a blocked cat or something; that does seem a bit low.

[Geo]

Ok I think we will go with that and order a new MAF. I doubt the cat is blocked as with the MAF disconnected the car pulls very well at high revs.

I got it to rev to the red line a few times just now and the voltage never went above 3.86V, and was usually down around 3.81/3.82.

[davy crockett]

The above trafic was really flat, to the point of being dangerous to drive.  Obviously the voltage figures on it were really low, but what was also very noticeable was how poor/slow the throttle response was - 5 seconds to build up to WOT in the workshop, no load. Thats a looooong time. So if the throttle response is similarly slow then that would be further confirmation.

Around 3.8v is well short of  4.25v.  I think you've got to go with MAF, especially if its ok with MAF disconnected. If its had a faulty EGR this could have damaged the MAF.

They are quite a common failure on trafic/vivaro.


Dave

[Geo]

This one is the same alright, it takes an age to get up over 4k.

I'll order a MAF on Monday and update on here once it is fitted.

Thanks again for all your help.