Check turbo vanes move freely oif all ok replace maf with a genuine Bosch part.

 

Turbo is ok, the maf sensor is new from valeo with equivalent references and I also tried a Bosch but It was from a Fiat

I also checked the wiring and seems to be ok.

 

It's some issue between maf read and map/dpf sensor pressure. It could be wiring, split hose or bad remap.

 

I only checked maf wiring, so I would discard maf and his wiring and also the remap because I tried a stock map and got the same result. Map sensor is also ok, at least comparing the real data and the desired.

I am going to check the hoses and wiring from dpf sensor, note that the dpf is empty.

 

Well, I checked dpf pressure sensor wiring and the hose and it's ok. I'm getting 7mbar from the dpf sensor with engine off and between 5 and 7mbar at idle, and revving a little bit it goes to 11mbar (not sure if the data I got is correct).

Also I'm a bit confused because in eLearn there is a picture from the sensor with two hoses and mine only have one as well as the dpf filter (3c at the image).

I tried also disconnecting dpf pressure sensor and then map sensor but still getting the same data from desired intake air quantity.

I wonder which parameters are used to calculate "desired intake air quantity", if there are more than mentioned (maf, map, dpf pressure sensor) but it's strange because all parameters from sensors seem to be ok.

Also I'm trying to test another ecu but I'm in the process.

 

Yes, that picture is probably for 2.0 JTDm model. 1.9/2.4 have DPF sensor on the firewall only with 1 input (before DPF) , second one is after DPF, which is integrated pressure/temp sensor, which hooks up straight to the DPF and just have some small wiring loom dipping to the DPF area.

Your idle readings for this sensor are normal.

I'm not ECU expert, but that desired air quantity most probably is just an equation of RPMs and current injector fuel correction values.

 

Yes, that picture is probably for 2.0 JTDm model. 1.9/2.4 have DPF sensor on the firewall only with 1 input (before DPF) , second one is after DPF, which is integrated pressure/temp sensor, which hooks up straight to the DPF and just have some small wiring loom dipping to the DPF area.

Your idle readings for this sensor are normal.

Oh thank you, so everything related with dpf is ok.

I'm not ECU expert, but that desired air quantity most probably is just an equation of RPMs and current injector fuel correction values.

I remember that, at least, two injector correnction values were a bit off, but I don't think to be the problem. RPMs gauge and data work good as well and the engine sounds good. Anyway, I will check correction values tomorrow if possible and post them. I will see if I have some logs as well.

 

Well, I forgot to check the injectors, wich I don't think to be the problem because the engine runs good and the problem still with engine shut off, but I tried unplugging some sensor with engine off but the desired intake air quantity didn't change. I am still waiting to try another ecu but if this doesn't work I don't know what can I check more. I don't get any error in MES from any unit of the car.

I could try a software update but I called the closer official workshop for AR, wich is at 50km from I live, for price of a software update and they just told me that only connecting the computer to check the car was around 60€ and then the mechanic will see if there is any problem or what they have to do. I suppose they will know what to do, and don't care if the software update cost 100€ or so, but I am also worried if they don't see the problem and I get a good bill for no update and nothing.

 

Desired intake air quantity and others data when engine off are not relevant. Ecu uses some predefined values and obd app show wrong data or unit too. In your case 3227 mg/i could be 327,7 mg/i typical from EGR map.

 

Ok, maybe you are right, but with the maf sensor connected I get the same error with engine running, at first it goes well but then you release the throttle or you stop and then you have no power because the engine goes into limp mode. And the live data shows this parameter going high up to 3200mg/i, it also oscilates but so strange and always between these number, never under 2000mg until you shut off and start again, and the same result. With maf discconected the engine runs good and the parameter stays between 400 and 1200 as it should, but with engine off it shows this number.

I will search for some logs with maf on and maf off and will post them if possible.

 

Easiest solution would be to try to find a 'friend' with another diesel 159 who can borrow you his working MAF for a short drive to rule out faulty MAF sensor in your car.
Disconnecting your current MAF sensor could give an improvement, if it is faulty, but the car will run from preprogrammed map, not current values and will still feel a little funky and won't give you the full potential from the engine.

 

Easiest solution would be to try to find a 'friend' with another diesel 159 who can borrow you his working MAF for a short drive to rule out faulty MAF sensor in your car.

Here is difficult to see some 159s and alfas in general

Disconnecting your current MAF sensor could give an improvement, if it is faulty, but the car will run from preprogrammed map, not current values and will still feel a little funky and won't give you the full potential from the engine.

Exactly, perfect definition, I am running the car this way because it's impossible to drive it with maf sensor connected.

 

Here there are two logs from MES/FES I did this afternoon, one with maf on and the other with maf off, in case someone want to see.

Test Logs - Google Drive

drive.google.com

 

You must do logs with 1s refresh or less, 5s is too lag.

With maf off is funny because it works like egr off, intake air quantity at idle is 460 mg/i.
With maf on it's like egr on, intake is 340 mg/i and after it has serious issues with maf data, it's reading too much.

So it looks like:

• maf fault
• maf wire
• ecu damaged or terrible remap (if with ori map you got the same maf higher readings at the end of log then forget remap)

 

Thank you for your reply, I will try again a supposed ori map and see what happens, last time I didn't even started the engine because I saw the number and I gave up. Also waiting for another ecu to try.

I checked maf wiring disconnecting from the ecu and maf to see if there was any short circuit but everything was ok, I also checked postives and negatives with the manual, in any case it could fail when the engine is running but is very strange.

Yes, it could be maf, but it's brand new from a "known brand" and with equivalent references from bosch. I know how bad this engines are with non bosch maf but for now in going to try ori map and ecu that I'm waiting and then I will consider trying a bosch maf anyway.

Last thing, how do I configure logs with 1s refresh? The rate option is always at MAX by default, do I have to put 60/min or less?

 

Better is FES/MES + KKL USB cable
com port delay: 1ms
kwp2000 timming: fast
Then you can read 8-10 parameters fast.

ELM 327 USB is ok too but I don't remember max parameters, I normally use KKL.

 

Ahh ok, I am using ELM, I will search for optimal configuration.

 

I have done two more logs with stock engine map and still getting the same result:

Test Logs - Google Drive

drive.google.com

I couldn't improve refresh time, I only noticed that if you only choose few parameters the refresh is around 1s, but if there is a lot of parameters it goes slowly.

 

I won't have new ecu to try until saturday 22, but I will try to test a bosch maf from another 159 1.9jtd from a friend of a friend (although it isn't 100% confirmed)

Another thing I forgot to mention when I tried stock map and maf ON is that the engine was very lazy, especially from iddle to 1700rpm. Going a road up hill in 2nd gear and less than 2000rpm was impossible, when with maf off you can go in 2nd gear and 1500rpm easily. Also going from standing I had to rev a lot more (than normal with maf off). And then on the highway the car was very slow, it cost a lot to go high rpm like the engine had 90hp, then it goes the error and it goes into limp mode and the car goes ok from standing but rev limit at 3000rpm and same power from the beginning.

Also something I think I didn't mention is that looking parameters, sometimes, the desired intake air quantity blinks from 3275mg/i to -200mg/i for 1-2s and then 3275mg/i again. Sometime ago, I checked ecu wiring to see if there was something visually strange, and while moving the wires it did that frecuently.

Could it be another wire short circuit with a maf one? I think it's very strange considering all parameters are ok and no errors on ecu.

I will keep updating.

 

51782033 - Bosch 0281002861

 

Thank you very much!!
I will look for one with that reference.

 

So, finally, it was the maf sensor 🙃, I found a second hand one from a fiat with the same reference and the problem has disappeared.

The only thing is that it doesn't read over 800mg/i so I don't have full power and it cost to rev over 2500rpm in 3rd 4rd 5th and 6th gear. Could it be because it's from an engine with less power or maybe it's partially broken?

I will change as well the MAP sensor with a new one because I noticed that it's not the original, althought it reads good but knowing the problem with a new not original maf ...

 

Problem disappeared! good for that

Now as about no more than 800 mg/i? Tested with remap map and ori map? If not read over 800 mg/i it's MAF died or ecu tune.

Interesting about MAP, other thing to fix. Second hand MAP is cheap, here in Madrid cost 5-10 € in scrapyards.

 

I tested with both maps ori and remap, with ori no more than 800 mg/i and with remap no more than 900mg/i. A friend told me that he got his maf sensor for his Leon 1.8t from exchange for 80€ so, on Monday I will ask at the same place for an exchange one from Bosch and I will have almost a brand new maf for half the price🧐

As you say MAP is cheap so I prefer to buy it brand new, at Oscaro.es it's like 35€.
I think this is the right one: https://www.oscaro.es/sensor-presio...vid=44&vident=bSmUgc3VpcyBEaW9ueXNvc6F1KjA8fphHwPX34qGl2ipphL3XDxYaH8DYY5dcpzg2

 

Ok. Your ori map is confiable? After with both sensors you must to stay sure about sensor are well coded in maps ori or remap. Looks like car had any rare mods.

 

Sorry, I don't understand what you mean. Someone got me the ori map from the remap, as the car came remapped and I didn't have the ori map. Do you mean I have to tune the remap or ori map with the new sensor? I don't know how to modify maps, I can only read and load maps so I will have to leave it to someone.

 

I mean you should check inside ori map and remap map that MAF and MAP sensors config is correct. You can compare ori vs remap to check all changes are ok.

 

Supposedly, everything is ok, two different people specialized at this, checked everything and both told me that it was all correct, even one of then told me that the remap was very good done.

I hope buying the correct maf for this car/engine fix the problem all the way. Surely next week I will have the answer.

 

Confirmed, MAF sensor was the problem all the time 🙃

Thanks for your help 🙋‍♂️