Desired intake air quantity from 1099.3 to 1053 all the time

[imandic]

Hi to all,
config is:

Alfa Romeo 156 1.9JTDM, year 2004., 170.000km, 103kw.

Error code on MultiEcuScan: P1237
Desired intake air quantity value: from 1099.3mg/i to 1053mg/i all the time.
I have tried with different MAF, MAS, air filter...No change.

When I disconnect MAF (air flow meter), two more errors appear:
P0110 - Air temperature sensor (air flow meter)
P0101 - Air flow meter

Car going like hell, consumption is fine, at idle is steady and fine...

Recently I have closed EGR (directly from exaust, near fan) and ECU is remapped to ignore error (MultiEcuScan for EGR: always at 1%).

In attachment find recording with MAF, at 68 seconds I have diconected MAF, and connected again at 632 sec.

What is strange:
After clearing errors, I can drive for 300km without error P1237, and if car is turned off and on again, error will appear after few km.
The same is if I clear errors, drive for 3km without errors, if I turn on car after 10-20 hours, error is here again after few km.

Do you have any ideas. Guy who closed EGR is sure that maps are ok (he claims that he checked everything few times).

[alfa156sarajevo]

Did you have this error before or after remap?
Sometimes some error does appear after remaping...

[imandic]

There was no error before remap.

But, I spoke few times with "remap master" and he claims that everything is OK with map and that he have done this procedure hundred times without problems.

[Flama79]

Not sure ... but I'll try to explain my idea.

It looks like a faulty EGR valve, probably it's only dirty and it doesn't close the gate properly or it's blocked.

Even if it's escluded by remap the cross-check with MAP data could give this error.

PS.: sorry for my bad english

[imandic]

Thanks Flame...

EGR pipe is totally closed before heat exchanger, so, there is no air in it from exhaust (INOX plate 1.5mm thick)...
Open or closed, it's the same, pressure is 0...And MES reports 1% for EGR...

[imandic]

Does anyone know the way how the "Desired intake air quantity" is calculated?
On standard maps with fully functional EGR?

[Flama79]

Ok... wrong idea

If the wirings are ok (especialy the egr pins) and you have check MAF and everything else I haven't any other (wrong) idea

Only a last (stupid) question:

Do you have swithed off EGR AND modified the Expected Air Quantity Map?

[Flama79]

I don't know the calculation behind "desired intake air quantity"

which ecu are we talking about? EDC15C7 or EDC16C39?

[imandic]

ECU: EDC16 CF3
EGR is connected but ECU check should be switched off by remapping (have no idea what's behind that)
Modified Expected Air Quantity Map? Have no idea, should be if this is a standard procedure when EGR is closed.

Conclusion:
I will have to ask "remapping guy" nicely to check everything again (or to put my old maps back)...

[Flama79]

I'm not a pro on chip tuning, but from what I know to avoid mil/dtc error it's not enough to remap only the expected air quantity/egr, but you ave to disable egr by changing a certain address from 001 to 000. The address is ecu dependent. If you do that you should read 0 or 1200 on desired air quantity all the time.

But I'm not a pro so ask to your remapper, that's the best.

Good luck