Berlingo economy and MAF sensor

[srx600]

Having owned XUD based Citroen ZX's for many years, and gained a good understanding of them, we have taken the plunge and bought an HDi (90) Berlingo (2003) with 50,000 miles on it, the main reasons being space and what I beleived to be improved fuel economy. Were generally pleased but the fuel economy hasnt lived up to expectations. It has a few other symptoms which I will also describe.
- Gentle driving with a view to economy with one person in the vehicle returns 44mpg (measured over two tanks), I was expecting over 50.
- A run up through France with two adults two kids and Bicycles on the back at 80mph gave 35mpg, I didnt expect it to be great but better than 35.
- The engine stalls very easily (unlike the ZX's which never stalled) this is most noticeable when cold but also happens when warm.
- The engine is fairly lumpy when cold, but smoothes out when warm.
- It pulls quite strongly from low revs and I found myself spinning the wheels on quick take offs, however the top end is fairly flat. There is no step in torque when the turbo spins up, unlike the ZX TD which was flat as a pancake then took of at 2,500 rpm. At one point I convinced myself it didnt have a turbo and had to crawl underneath just to check. I expected it to have a more linear torque curve than the ZX TD but not as flat as this.
Other than that it goes fairly well, and we are quite pleased with it.

I have read that the MAF can deteriate over time and cause some of the above symptoms. I beleive they are difficult to test, but one approach is to disconnect the MAF and see if the performance changes.
So finally to my questions
- If the MAF is disconnected on the Berlingo, will the CPU/BSi detect its disconnected and flag an error ?.
- If an error is flagged how can I clear it ?. I understand some of the scanning tools available dont work well on the Berlingo because Citroen only implemented parts of the OBD11 spec. Are the error code readers/tools different in this respect, if so can anyone recommend one that does work

Cheers for any help/advice you can offer.

[nick]

I have read that the MAF can deteriate over time and cause some of the above symptoms. I beleive they are difficult to test, but one approach is to disconnect the MAF and see if the performance changes.
So finally to my questions
- If the MAF is disconnected on the Berlingo, will the CPU/BSi detect its disconnected and flag an error ?.

Hi,

Your symptoms could be related to a dodgy, or perhaps just dirty MAF. But then the HDi, particularly in 90 bhp form, does tend to have fairly flat performance compared to the old TD. If anything a faulty MAF will cause poor low down performance, with the top end being normal.
Common rail diesels do seem to stall more easily than older tech diesels though. The worst I have known in this respect was a Mondeo TDCi I used to drive - the HDi isn't bad in comparison!

With mine I can plug and unplug the connector to the MAF with the engine running and hear the engine note change as a result, but it doesn't ever bring the engine management on.

[srx600]

[quote="nick"]
With mine I can plug and unplug the connector to the MAF with the engine running and hear the engine note change as a result, but it doesn't ever bring the engine management on.[/quote]

As an update I disconnected the MAF and went for a short drive, and I couldnt tell the difference between connected and disconnected. Will try again today.
Cheers I will try this as well.

[jeremy]

Be fair to it - its aerodynamics are - well - lets say not as good as a ZX.

Your TD ZX had a top speed of about 111. The Berlingo with the same power has a top speed of 98 which is the same as a 1.9D (late) ZX could manage on 68 BHP

So you could say that to do 98 your Berlingo needs 22 BHP more than your ZX did.

[srx600]

[quote="jeremy"]Be fair to it - its aerodynamics are - well - lets say not as good as a ZX.
[/quote]
Its a fair point, but I have spoken to someone with the same model who used to get better fuel consumption than we are (hes now sold it).

[srx600]

[quote="nick"]
With mine I can plug and unplug the connector to the MAF with the engine running and hear the engine note change as a result, but it doesn't ever bring the engine management on.[/quote]

I couldnt tell any difference when I did this, does yours getting lumpy/change speed when you disconnect it ?

[nick]

Strangely it seems to neither affect the engine speed or make the tickover lumpy, but the engine note does change very noticeably which I think is due to the ECU either cutting the exhaust gas recirculation or perhaps altering the injection timing slightly when the MAF is unplugged. The induction noise just sounds different somehow.

The real test of a faulty MAF is to drive the car with it unplugged. Under normal circumstances there should be an obvious drop in power with the MAF disconnected. The MAF on mine was so bad however it actually ran better with it disconnected!

[wheeler]

the engine note does change very noticeably which I think is due to the ECU either cutting the exhaust gas recirculation

It is the EGR as the airflow meters main function is to monitor EGR. If its disconnected then it doesent know how much its EGRing.

[srx600]

I did a simple roll on test between 40 and 70 with the MAF connected and disconnected. The car is around 25% quicker with the MAF connected so its clearly doing something.
The point about the engine note changing when the MAF is disconnected is interesting, could the fact that mine doesnt change note be down to a stuck EGR valve and could this effect economy ?. If so is there any easy test ?

[Stunned Monkey]

The too-easy-to-stall symptom was one of my characteristics of a failing MAF sensor. However, it also started behaving much more like an XUD, only boosting at 2500. Only after I got a new sensor and cleared off the ECU errors (FWIW my telltales were both rich AND lean conditions reported in ECU) did it go back to boosting properly

[myglaren]

I was just talking to a colleague at work yesterday who had had to take his Berlingo to the dealer last week while away on holiday.

It wouldn't idle smoothly and was either idling far too slow or far too fast.
The diagnostics threw up a defective idle solenoid which was replaced - for £10 - it seems it was subject to a recall.

The Berlingo was a 52 plate as it was registered 31/12/02 but should be a 03 as the model shouldn't have been released until the following day - something like that anyway.

While he was there they adjusted the throttle cable and he scared himself to death driving it away as it was much more powerful and responsive.

He had had it chipped but taken the chip out when taking tha car to the dealer as it throws the diagnostic computer out. The car is now far better than it was with the chip.

[nick]

The point about the engine note changing when the MAF is disconnected is interesting, could the fact that mine doesnt change note be down to a stuck EGR valve and could this effect economy ?. If so is there any easy test ?

I think the change in engine note could be down to the vacuum operated "air doser" butterfly in the air intake which works in tandem with the egr valve, rather than the egr valve itself.

They stopped fitted this air doser to the HDi in early 2003, my 2002 car has one but its quite likely your 2003 won't, hence the reason you're not hearing any change in engine sound.

[meexi]

hi my 2001 hdi picasso seems to have symptoms like this where is the MAF sensor?

[nick]

where is the MAF sensor?

In the air intake, usually just after the air filter housing.

[deian]

Common rail diesels do seem to stall more easily than older tech diesels though. The worst I have known in this respect was a Non-Citroen TDCi I used to drive - the HDi isn't bad in comparison!

The TDCi and the HDi are the same engine.