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Model specific boards => Golf mk4 => Topic started by: Chris. on 21 May 2012, 21:51

Title: AGU limp mode
Post by: Chris. on 21 May 2012, 21:51
We done a 20Vt conversion into a bora over the weekend and on a mapped ECU, the boost is low and certainly isnt pushing the power a mapped k03s would do.

Maf readings are showing 148.19g/s which is 185bhp so its making power.

Only issue i have is that I am only getting 5.1% duty cycle on the N75 so its in limp mode and not giving full boost to turbo.

There is a error on the maf - signal too low (16486), which comes back all the time, tried 2 used mafs for now, but need to try my known working MAF on it.  Same with N75 valve.

Thing is, would the maf fault code cause the car ecu to drop into limp mode?

Any help appreciated.  Really need this sorting before we go for more power.


Chris

Title: Re: AGU limp mode
Post by: cullygti on 21 May 2012, 22:10
i dont understand all them numbers chris but my maf is apparently naffed and as never thrown me into linp mode just runs a bit rich
Title: Re: AGU limp mode
Post by: xxChrisxx on 21 May 2012, 22:30
Maf readings are showing 148.19g/s which is 185bhp so its making power.

It's not necessarily the case. The %0.8 trick is just a rule of thumb and has to be taken with a pinch of salt.

Quote
Thing is, would the maf fault code cause the car ecu to drop into limp mode?

It'll make it run on a default map as long as there is no signal, as it knows it's not getting the correct readings.
It may not be the MAF its-self, it could be a wiring or harness fault.

Title: Re: AGU limp mode
Post by: Chris. on 21 May 2012, 22:39
Maf readings are showing 148.19g/s which is 185bhp so its making power.

It's not necessarily the case. The %0.8 trick is just a rule of thumb and has to be taken with a pinch of salt.

From the figures ive seen over the years, and speaking to people who map these day in day out, the 0.8 trick is almost certainly bang on in near enough all cases ive seen from rolling road graphs and logs ran at same time.   Of course, its never going to be 100%, but it does give a damn good indication.

I have a feeling its wiring related issues.  Going to try investigate further tomorrow if I get chance.
Title: Re: AGU limp mode
Post by: Wazzzer on 22 May 2012, 17:32
225bhp predicted by 0.8 calculation, three days later ran 222.2 on JKMs rollers :wink:
Title: Re: AGU limp mode
Post by: Chris. on 24 May 2012, 22:33
Like a boss....i fixed it.  Fuse 43 controls the MAF lives, Lambda sensor and evap tank lives. 

Full boosties restored and shafts spat out.  oops