JTD 8V strange MAF reading after MAF change

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JTD 8V strange MAF reading after MAF change

Postby sike_145 » Fri Jun 22, 2018 12:00 am

Hi,
I have a doubt about MAF reading from my original (Bosch 0 280 218 113 on car, but OEM No. is 46559804 from Eper for my car) old MAF and new MAF (Polcar E02-0075).

I remaped my car (Alfa 156 1.9 JTD 8V 85kw) few years ago ( from time to time change and "polish" maps) and I noticed that now airflow is lower than a year ago...so I changed MAF with Polcar E02-0075 (on site that sells it states that this is replacement for my original one) but now I have a very high readings for airflow so I'm not sure is this a right MAF for my car.

Readings for airflow with original MAF are here:
old_maf1.JPG

old_maf2.JPG

old_maf3.JPG


And readings for airflow with new MAF are this:
new_maf1.JPG

new_maf3.JPG


Can someone help and tell me what are expected correct airflow readings for this engine for boost of 2400-2450 mbar absolute and 2000-4000 RPMs?
Is a new MAF incorrect for this engine?

Thanks!
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Re: JTD 8V strange MAF reading after MAF change

Postby jurebv » Fri Jun 22, 2018 9:04 am

MAF readings are too high

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Re: JTD 8V strange MAF reading after MAF change

Postby ceecee » Fri Jun 22, 2018 6:39 pm

Your new MAF is bad quality or incorrect for your engine. Polcar is unknown for me (Acme).

It looks like Polcar is a 16v MAF 640 kg/h but your MAF is 480 kg/h.

Re-check Bosch reference on old MAF, check your VIN in ePer and buy original Bosch.

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Re: JTD 8V strange MAF reading after MAF change

Postby sike_145 » Fri Jun 22, 2018 9:31 pm

Actually, I found that on my car was fitted wrong MAF, possibly by previous owner. It was fitted with Bosch 0 280 218 113 which is for 16V and 150BHP engine version, and for my 8V 115BHP correct one is Bosch 0 281 002 309.
Maybe is that reason why it never reads more than 1000 mg of air over 3000 RPM even boost is over 2400 mbar.

Polcar E02-0075 is replacement for 0 281 002 309 but obviously is very bad quality:
polcar.JPG


It would be nice to find MAF characteristics curves for all this models so I could compare them and maybe correct MAF linearisation map in ECU to correct readings from new MAF.

It is very strange that replacement MAF have so wrong readings...

It looks like original Bosch is only option.
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Re: JTD 8V strange MAF reading after MAF change

Postby ceecee » Fri Jun 22, 2018 9:56 pm

Typically Unijet CF2-CF3 8v 80->115 use 480 k/g MAF.

I think your linearization inside ECU is ok for original 480 kg/h because with Polca MAF it reads higher mg/i, anyway you can check it if you know.

Solutions: install correct MAF or remap linearization to Polca MAF.

About normal mg/i with 2.400mb it depends on several things like EGR, intake dirt, exhaust flow... as example my 8v CF3 with stock exhaust and 2.400mb it reads 1150-1200 mg/i at low revs and 950-1000 at high revs, 510-520 kg/h max.

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Re: JTD 8V strange MAF reading after MAF change

Postby Deman » Sat Jun 23, 2018 8:56 am

On these cars MAF is not a very important thing; so as to carefully choose. If EGR is muted, it is closed. It only limits smoke.
This forum has a topic how to switch from MAF to MAP sensor.

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Re: JTD 8V strange MAF reading after MAF change

Postby sike_145 » Mon Jun 25, 2018 8:41 pm

Can you send link on that topic? Thanks.

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Re: JTD 8V strange MAF reading after MAF change

Postby lyecon » Thu Jul 05, 2018 2:07 pm

sike_145 wrote:Hi,
I have a doubt about MAF reading from my original (Bosch 0 280 218 113 on car, but OEM No. is 46559804 from Eper for my car) old MAF and new MAF (Polcar E02-0075).

Readings for airflow with original MAF are here:
old_maf1.JPG

Thanks!


Look, any --- MAF is unreliable, shitty piece of hack of a hardware. I can change the MAF readings just by washing the MAF sensor, and the readings will be much higher for several days until the oil vapor from the engine fouls it and the values drop. Next, your actual air flow depends on many factors, oil condition, turbo state and fouling, air filter age, actual EGR flow, outside air temperature and absolute pressure, and a million viariables inside the ECU.

None ECU critical systems should ever depend on MAF readings, and especially not in an open-loop control.

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