NefMoto

Hello guys. After a couple of years.

What I'm about to present is a problem that I faced long time ago. Then, I moved to another city, left the car to my mother. Now I'm back and I'd like to fix it once and for all.

I'LL INCLUDE A SUMMARY at the bottom, just in case ;)

1st) I don't have logs. I did them some time ago but they're in a dead HDD. I perfectly remember those logs though. However, If you consider you need them in order to diagnose what's happening, tell me what variants to log and I'll get me7logger working on my car (quite tedious).

2nd) My car is a MK4 Golf from the end of 2001. AUM, me7.5 wideband 06A906032HJ

3rd) It all worked like charm. I learnt how to modify its flash myself, did some iterations... Good. One day MAP sensor (2.5bar) says goodbye. Took it to the shop and they wrongly installed a 3bar one...

4rd) Later I tried to fix it, that shop wasn't an option anymore, so I decided to do it my way, linearization. I corrected DSLGRAD and DSLOFS following FR/S4Wiki.

5th) Pressure readings now make sense... More or less. But Lamdas don't. Tried adjusting DSL a bit more, nothing.

6th) While iddilng, requested lambda is 1 and actual 0.75 (Both VCDS and me7logger, LAMSONI 0.75, everyother lambda, leaner). Under load it works OK. But the deviation at idle is so huge that adaptations go out of range each couple of months.

7th) I tried to back-trace through the entire FR both Lambda and DSLXXX and I saw absolutely nothing relating both.

8th) Before you ask: I tried 2 stock files. One with stock DSL. Lambdas worked ok, even with incoherent pressure readings. Another stock but with corrected DSL, Actual lambda goes stupid rich at iddle. So is that fu*@*@ mod for sure what's messing me up.

9th) I can only see 2 scenarios: A) I'm just blind and there's relation between those variables in FR that I didn't see. B) There isn't but me7sum goes crazy with that particular mod and changes a value in some random cell that causes my problem.

10th) For sure it's easier to buy the right MAP. I just don't want to, this has become a personal goal.

SUMMARY:

- Wrong MAP sensor installed, 3bar instead of 2.5
- I try to fix readings by DSLGRAD and DSLOFS
- It gets better regarding pressure readings but goes crazy with lambda
- I lost my logs but I remember them. At iddle requested is 1 and actual is 0.75, works OK under load. If you still need me to me7log any variable, just tell me
- It's absolutely verified, that particular change in DSL is causing that lambda beheaviour
- I didn't find anything in the entire FR relating both DSLGRAD/OFS and Lambda

Thanks a lot for your time,
Diego

Log 115.4 with vcds @idle
Should be ~1000 mbar
Poor dslgrad/dslofs tuning causes wrong rl calculation and that's the key of bad fueling

When replacing stock 250 kPa Bosch PS (standard characteristic curve type 1) to 300kPa sensor (curve 1) you must change:
DSLGRAD from 541 hPa/V to 659
DSLOFS  from -16.4 hPa to -63.5 
If new sensor has curve type 2 this values must be appropriate recalculated.

Thanks guys.

For 115/4 channel in vcds. Yes, pressure readings are ok.
For dsl calculation, I don't remember the exact values but I'll take a look at them. I'll also share its p/n just in case it's type 2 curve.

And a little detail. If poor dsl calibration causes rl bad calculation... How is it possible that lambdas are ok with stock dsl and 3bar map?

No reason to discuss here wo logs

Ok, I'll log Vcds channels 114, 115 and 031 and I'll post them

Thanks

ME7Logs are preferred anyway, unless you're posting single values

1) pressure + voltage with engine off
2) pressure + voltage at idle
3) pressure + voltage at a constant part throttle (preferably near req load = 100)

I take note. Thanks nyet

also log ambient pressure and compare to pressure sensor with engine off

Hello,

This is a nonsense. I've just logged it and both actual and requested lambda are 1.

Maybe it's got something to do with warmer weather? I don't know. Anyway, it wasn't a product of my imagination cause there was a dtc in the memory saying "System too rich"

If this happens again I'll let you know and I'll post logs.

Thank you all for your willingness to help me.