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Model specific boards => Golf mk4 => Golf mk4 TDI => Topic started by: mrapoc on 03 June 2012, 17:31

Title: Low power, struggling economy
Post by: mrapoc on 03 June 2012, 17:31
Sounds a bit like Britain at the moment!  :wink:

Its a 115 AJM, I remapped it to "140" using blacksmoke - problems were present before remap

Had the cambelt changed about 1k miles ago by midlandvw (top chaps) and was told it felt so low, more like a 100bhp

The way I see it, its low on power, I put the foot down more as it starts slowing down when I try to hold it at a decent MPG, hence having less MPG.

Turbo vanes have been cleaned, actuator moves freely, changed maf and map, changed thermostat and coolant sensor. EGR cleaned and blanked off, new n75 valve.

It is overboosting by 400mbar but would this result in less power too?

Short term plans before selling the damn thing is to give it basic service (gave it full last year)

Tried to do clean intake manifold, but it was too hard and the bolts were stuck hard.
Planning to decat it next week - can this help???

Cheers
Title: Re: Low power, struggling economy
Post by: Steve_PD on 03 June 2012, 18:06
Have you had it on a rolling road to see if it's actually down on power?

If it is down on power remove the map and see if it is still down.
Title: Re: Low power, struggling economy
Post by: EsSeX dAn on 03 June 2012, 18:31
did u use a bosch maf or a cheaper one? the cheaper ones can cause problems. was it worse after the cambelt got done? could be timing is out or something. can you hear the turbo boosting atall?
Title: Re: Low power, struggling economy
Post by: mrapoc on 03 June 2012, 19:04
Literally everything I have done since owning the car has not made much/any difference to economy or power.

The map if anything makes it a better drive at lower revs, still bad enough for midland vw to say its worse than a stock 115. I used a genuine bosch one from tps - this did help a lot in regards to turbo lag.

Do you reckon the best thing to do at this point is get the stock map on, go out logging as much as vcds (free) allows and then see if a decat helps.

As to the rolling road, i don't know of any in my area (telford, shrewsbury and ludlow) which exist and cost a fortune  :sad:

Cambelt hasn't effected it at all - I presume they do check timing when they do cambelt?

The turbo is quite loud in my opinion, you can hear it spooling alot and you can even hear a whirrrrr noise when you turn the engine off!
Title: Re: Low power, struggling economy
Post by: Steve_PD on 03 June 2012, 19:10
Cant see a decat doing anything apart from how it sounds.

Literally everything I have done since owning the car has not made much/any difference to economy or power.

You might be chasing problems which don't exist :undecided: :lipsrsealed:

First thing Id be doing is getting it on a RR. R-tech is not too far from you and the rollers are very accurate! See what power its actually putting out with/without the map. And go from there
Title: Re: Low power, struggling economy
Post by: mrapoc on 03 June 2012, 21:16
That's indeed how it seems and I might be better just selling it and getting a 130 or equivalent

Nick did say that a blocked cat can cause the said overboost

It's just working full time weekdays I don't really get the chance to visit Rtech but i'm sure if I could they would/could say whether its right or not
Title: Re: Low power, struggling economy
Post by: Rhyso on 04 June 2012, 01:25
Pull a sicky / book a day off

First things first; put the car back to standard and work out whats wrong
Title: Re: Low power, struggling economy
Post by: mrapoc on 04 June 2012, 03:03
Ok then,

job 1 tomorrow, load stock map

job 2, go get some wot logging done
Title: Re: Low power, struggling economy
Post by: mrapoc on 04 June 2012, 14:40
Back to stock and done a 3rd gear WOT as best I can

Here are logs turbo and maf respectively


(http://i2.sqi.sh/s_3/eKf/turbo.png)

(http://i2.sqi.sh/s_3/eKf/maf.png)

 :undecided:
Title: Re: Low power, struggling economy
Post by: Rhyso on 04 June 2012, 14:49
Your boost is rather erratic  :undecided:  it has the intital overboost which is fine but then it cant seem to control whats going on  :undecided:

have you tried driving it with the maf unplugged?
Title: Re: Low power, struggling economy
Post by: mrapoc on 05 June 2012, 18:53
ill try that and log a wot too

almost as if the n75 cannot adjust boost or actuator problems?
Title: Re: Low power, struggling economy
Post by: mrapoc on 05 June 2012, 22:51
Wondering what could be making these weird boost readings

If someone could answer if it could be what i'm guessing

1) Blocked cat
2) Vacuum leak around brake booster (only place i havent checked)
3) Intake manifold (I havent cleaned this and its done 160k)
Title: Re: Low power, struggling economy
Post by: mrapoc on 06 June 2012, 09:35
I don't want to be chasing this car any more and don't have the time as of late.

In fact the only reason i'm still bothering is the recaro interior  :laugh: tis yummy!

Whilst i'm working tomorrow a local garage is decatting it and doing the intake manifold for me for about £100. I couldn't get the manifold off last time I tried (probably due to using alan keys and not having a proper socket set!)

TL;DR Buy decent socket set and it will always do you right  :smiley: