Power Drop (unusual One This!)

[latrine]

Hi all

 

i've noticed a lack of power at the lower revs (upto 1500) on my 115 tdi

 

The Gal is simply not as responsive or pulling as it usually does at those low revs

 

As soon as it hits 1500rpm then all's fine and the think takes off as usual

 

I ran it yesterday with the MAF sensor unplugged - that improved the acceleration and power at those low revs but there was significantly less power in the higher revs. My understanding is that if you have a knackered MAF then the Gal is so much better with it unplugged. My situation is like that at the lower revs but not at the higher revs - she pulls/runs fine past 1500 rpm

 

It's as if there is no guts before the turbo kicks in at 1500

 

Anyine any thoughts/ideas please

 

many thanks, as ever

[gio]

Hi all

 

i've noticed a lack of power at the lower revs (upto 1500) on my 115 tdi

 

The Gal is simply not as responsive or pulling as it usually does at those low revs

 

As soon as it hits 1500rpm then all's fine and the think takes off as usual

 

I ran it yesterday with the MAF sensor unplugged - that improved the acceleration and power at those low revs but there was significantly less power in the higher revs. My understanding is that if you have a knackered MAF then the Gal is so much better with it unplugged. My situation is like that at the lower revs but not at the higher revs - she pulls/runs fine past 1500 rpm

 

It's as if there is no guts before the turbo kicks in at 1500

 

Anyine any thoughts/ideas please

 

many thanks, as ever

 

believe my galaxy 115 lack some lowdown grunt, although have only had it 5 weeks, did expect more punch.

MAFs do stop working properly over time and it does go unnoticed.

have ordered a new one from my local ford dealer

[latrine]

thanks

 

would you let me know how you get on when you change the MAF?

[NikpV]

My understanding is that if you have a knackered MAF then the Gal is so much better with it unplugged.

 

 

depends on the state of the maf - ours still ran better with the maf connected (did timed distances up a medium hill) butwith a new MAF the difference was dramatic. How many miles has it done ??

 

 

have a look here

[gio]

thanks

 

would you let me know how you get on when you change the MAF?

 

YES i will. today i have cleaned my old MAF using alcohol bought from the chemist, its called [isop... something]

as yet have not driven it to see what if any diference there is, but i intend to get a new one maybe this weekend or

the wekend after...

[NikpV]

thanks

 

would you let me know how you get on when you change the MAF?

 

YES i will. today i have cleaned my old MAF using alcohol bought from the chemist, its called [isop... something]

as yet have not driven it to see what if any diference there is, but i intend to get a new one maybe this weekend or

the wekend after...

 

Isopropanol (iso - propyl alchohol) C₃H₇OH

 

I didn't think that the Thick film sensors (Mk2 onwards) respond to cleaning - unlike the hot wire type (earlier models)

[gio]

nickpV please explain?

 

Does that mean i have wasted my time trying first to clean my MAF?

 

It looks identical to my ALFA jtds MAF, and nothing ever mentioned on there about different types of MAF..

[NikpV]

older mass air flow sensors used a heated wire which cooled as air flowed past it - the cooling changed its resistance and so the air flow could be sensed, they were sensistive to the wire getting dirty and so not cooling as much for the same airflow. You could clean the wire carefully and it would make a big difference.

 

The more modern thick film type sensor doesn't suffer as much with dirt but they do degrade over time -

 

If you look at the link above my sensor was extremely clean when it came out - I had tried cleaning it with IPA prior to changing it but it made no difference and no dirt came off the sensor

[gio]

older mass air flow sensors used a heated wire which cooled as air flowed past it - the cooling changed its resistance and so the air flow could be sensed, they were sensistive to the wire getting dirty and so not cooling as much for the same airflow. You could clean the wire carefully and it would make a big difference.

 

The more modern thick film type sensor doesn't suffer as much with dirt but they do degrade over time -

 

If you look at the link above my sensor was extremely clean when it came out - I had tried cleaning it with IPA prior to changing it but it made no difference and no dirt came off the sensor

 

thanks for the reply.....

[Guest Cepheus]

unplugging the MAF will make the ecu resort to default values for air flow volume so won't make it more responsive, but should make the overall rev range more equal when accellerating. Most MAF faults affect either top or low end rev range issues, so unplugging it to restore to default values will cure the specific top end or low end problems you are encountering and therefore "prove" the MAF to be at fault.

 

HTH

[NikpV]

The problem with ours was that it didnt prove that there was a MAF fault

 

see here

 

When it was disconnected it ran much worse that when it was connected - so by the normal reasoning you would say it wasn't faulty. However putting a new one in made as much difference again - as you can see from the thread I only started to get the feeling it was getting sluggish at higher speed and a slight drop in MPG.

[latrine]

thanks for all the replies

 

as usual, this forum and its members. prove invaluable

 

i disconnected the MAF again last night and the car is noticeably better to drive at the low rev range i am expericneing probles at - it just picks up so much better in all gears

 

seems that a MAF is what i need

 

do i need to take off the existing MAF to locate the part number?

[tim-spam]

If you quote the engine type code (probably AUY) and year of manufacture, GSF will be able to supply one to you through the post.

[springen]

Hi all

 

i've noticed a lack of power at the lower revs (upto 1500) on my 115 tdi

 

The Gal is simply not as responsive or pulling as it usually does at those low revs

 

As soon as it hits 1500rpm then all's fine and the think takes off as usual

 

I ran it yesterday with the MAF sensor unplugged - that improved the acceleration and power at those low revs but there was significantly less power in the higher revs. My understanding is that if you have a knackered MAF then the Gal is so much better with it unplugged. My situation is like that at the lower revs but not at the higher revs - she pulls/runs fine past 1500 rpm

 

It's as if there is no guts before the turbo kicks in at 1500

 

Anyine any thoughts/ideas please

 

many thanks, as ever

 

That sounds like exactly the problem I'm having too. It started as a kind of 'flat-spot' at about 1800 rpm, but is now like that above. I too have only had the car a couple of months and thought it was perhaps a 'feature' of the PD engine. My old Alhambra mk1 tdi (90) never had this problem. It's been back to the dealer for them to check for codes logged, but they could not find a problem. (does the MAF not register any fault codes ?) They checked the Turbo power and all was fine. I'll try disconnecting the MAF and see what happens. What a great site this is !!

[NikpV]

does the MAF not register any fault codes ?

 

from what we've seen on here its not good for logging faults - more often as not it doesn't.

 

Seems a very low mileage/age for the normal MAF problem though

[springen]

I agree about your age/milage comment. It's rather clouded the new car 'feel good' factor.

 

I normally service/maintain my cars myself, but didn't want to mess with this one too much as it is still under warranty. But I think I will have a check over it myself - from what I've read on hear I'm a little reluctant to let the dealer get their hands on it to totally screw it up !!

[latrine]

Hi all - just an update on my problem

 

went to GSF today and got myself a new bosche MAF -

[NikpV]

ding - another satisfied customer :lol: