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Author Topic: Overfuelling during starting, 1.8t ME7.5  (Read 11503 times)
Ken-1
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« on: May 11, 2014, 11:50:23 PM »

Hello,

I´m trying to get my A4 1.8t B6 to work properly with E85 fuel. While car is running everything seems fine, STFT are quite ok but getting better all the time when KFKHFM is corrected. The problem is starting the car when engine warm or quite warm, it overfuels the engine and starting goes really bad. Many attempts needed before it keeps running.

The car is equipped with RS4 MAF and 1000 cc injectors making the tuning a bit challenging. The throttle housing is from some Mercedes I believe also.

The injectors have part numbers: 0 280 158 117 , 81187 , 23-09-09 041344. Fuel pressure is set to 3.5 bar (50 psi), TVUB is according to this: http://www.boschdealer.com/specsheets/1000cc.pdf and KRKTE is 0.0443 (fuel E85).

It seems to me like the MAF is showing WAY too high values during starting and this causes a lot of fuel to be added, I could of course correct this with KFKHFM but the the STFT is off in those areas when engine is up and running.

The attached start.jpg includes some pumping of the pedal to keep the engine running, but it failed.

Can I limit the fuel in some way at the start or what should be done?

BR. Kenneth


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titi65
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« Reply #1 on: May 13, 2014, 02:52:39 PM »

I've not monitored mine at starting, but it could be interesting . . .
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Ken-1
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« Reply #2 on: May 15, 2014, 01:47:20 AM »

Hello again,

I believe that the different throttle housing may be one cause for the bad behaviour, the current one installed in the car is 70 mm in diameter and I do not know where the KFWDKMSN and KFMSNWDK maps are in the bin so I have not scaled them. So in starting the RPMs are really going up and down when ME7.5 is trying to control the idle.

Can someone maybe assist me in locating the KFWDKMSN and KFMSNWDK in the attached bin, or do you have an idea of what defined ols file I should look in to get an idea of were to search for the maps. I tried to compare to a Audi TT .ols file but that does not match up at all.

Car is A4 1.8t 2003 5speed manual, wideband.

BR. Kenneth
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terminator
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« Reply #3 on: May 15, 2014, 09:42:36 AM »

1D7D0
1DBFA
 Wink
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jimmcgee5
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« Reply #4 on: May 15, 2014, 02:40:40 PM »

have a look through this thread , same ecu  Grin http://nefariousmotorsports.com/forum/index.php?topic=5563.0title=
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Ken-1
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« Reply #5 on: May 16, 2014, 12:32:32 AM »

1D7D0
1DBFA
 Wink

Thank you!

This helped a lot, to early to say if it´s fixed the problem now but the car started better and was also alot smoother to drive.

BR. Kenneth

Edit:
The car improved a lot with the scaled tables for the larger throttle housing. This is a car that was bought modified second hand so there are a lot of surprises to be found =)

This came up while  scanning with VCDS

16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal

17526/P1118/004376 - Oxygen (Lambda) Sensor Heating; B1 S2: Open Circuit

17834/P1426/005158 - EVAP Purge Valve (N80): Open Circuit

The first one is due to map sensor having been replaced by a 3.5 bar unit, so the scaling for that I would need to try and find somewhere.

The other two are just because these are removed from the car, but not from the software at the moment, if anyone sits on any info I´m all ears and very grateful.

/Kenneth
« Last Edit: May 16, 2014, 09:14:12 AM by Ken-1 » Logged
Ken-1
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« Reply #6 on: May 16, 2014, 02:51:11 PM »

Hello,

Still the same issue, tried to start the car after having it turned off for 15-20 minutes and it was totally impossible. Probally took most of the life out of the starter motor while attempting to start and put ½ liter of 85 in the oil sump. Not good.

Is there anything that can be done?

Is it possible to limit the load, measured airflow or something after start? Now it drowns in ethanol.

BR. Kenneth
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titi65
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« Reply #7 on: May 16, 2014, 02:54:36 PM »

Are you sure about your O2 Sensor and your MAF ?
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Ken-1
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« Reply #8 on: May 16, 2014, 11:58:16 PM »

Are you sure about your O2 Sensor and your MAF ?

Hello,

Well, no actually. But they seem fine, O2 sensor measures the same as the Vems O2 sensor installed in the car, and when driving the air flow from MAF is very reasonable I would say.

Can all these issues be coming from RS4 MAF just being too big for 1.8t? But I guess other people have made it work?

/Kenneth
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titi65
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« Reply #9 on: May 17, 2014, 02:17:39 AM »

Well, if you changed the MAF, and the throtle, especialy not telling it to ME7, it might not be surprising that some things are a little . . .moving.

I don't saying it can't work, but it might be necessary to work on it to make it work (and clean, like in starting phase).

As usual, it's not because other do as it's clean...

Do you have recalibrate the MAF in ME7 ?
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Ken-1
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« Reply #10 on: May 17, 2014, 06:45:41 AM »

Well, if you changed the MAF, and the throtle, especialy not telling it to ME7, it might not be surprising that some things are a little . . .moving.

I don't saying it can't work, but it might be necessary to work on it to make it work (and clean, like in starting phase).

As usual, it's not because other do as it's clean...

Do you have recalibrate the MAF in ME7 ?

Hello,

Yes of course the MAF is scaled as it should in ME7. Also the throttle maps mentioned above are now adjusted for the 70mm throttle housing.

But still there are issues in the starting.  Just wondering if I should give up and go for a S4 MAF or if someone is driving around with this MAF on a 1.8t and has it working like a charm?

/Kenneth
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titi65
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« Reply #11 on: May 17, 2014, 08:46:47 AM »

I see you've changed injectors, and running in E85.
Are you sure about your KRKTE ?

Did you tweaked the cold start ?

Is the injectors are 1000cc ?
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Ken-1
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« Reply #12 on: May 17, 2014, 09:28:05 AM »

I see you've changed injectors, and running in E85.
Are you sure about your KRKTE ?

Did you tweaked the cold start ?

Is the injectors are 1000cc ?

Hello,

Yes the injectors are changed, I posted the Bosch numbers I found on them higher up. I´m not sure were they are from or if they even are 1000cc, this is just what I was told when i bought the car.

KRKTE is now at 0.045 and STFT is ok as long as load is above 30 %, below that it is a bit tricky. I´m suspecting that the MAF is just too big due to everything being quite OK at some engine load and g/s air but at low load it´s not so good. Also this is what more experienced ME tuners told me that could be the case. But starting should still be possible according to me...

FKSTT is increased (very much) due to the E85 fuel but FNSSM I have set to 0 above 40 deg engine temp, just to avoid pouring too much fuel in the engine at start.

Thanks for the input!
/Kenneth
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titi65
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« Reply #13 on: May 17, 2014, 03:21:48 PM »

I've just checked, your injectors are 550cc, not 1000.
Your TVUM might not be correct.

If you have a large O² Sensor, you can check that KRKTE is good at full load (you should be near your lambda's consigne).
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ddillenger
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« Reply #14 on: May 17, 2014, 03:25:02 PM »

I've just checked, your injectors are 550cc, not 1000.
Your TVUM might not be correct.

If you have a large O² Sensor, you can check that KRKTE is good at full load (you should be near your lambda's consigne).

His injectors are fine. 90 percent of high flow EV14's are modded 117's.
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