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(Post Link) post #1 of 11 Old 23-11-13 Thread Starter
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Desired air intake problem

Hi,
I have Alfa Romeo 156 1.9 16v mjet.
Some Multiecuscan values about desired and actual air intake quantity are confusing me.
There is a log in attachment to see what I'm talking about.
Short story,when desired air intake quantity is 1200,actual is about 850-880.
I cleaned turbo,cleaned complete intake,but still same values.
EGR is off

If someone could help,I would be grateful...

nova diag.xls
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Is there a problem power wise ?
Did you clean the maf ?
As you have egr blanked , look for splits in air intake hose to turbo.
What is the maf reading at idle once warm ? Should be around 485mg/i
If you did and still low power, does unplugging the maf restore power ?
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Quote:
Originally Posted by sussexa View Post
Is there a problem power wise ?
Did you clean the maf ?
As you have egr blanked , look for splits in air intake hose to turbo.
What is the maf reading at idle once warm ? Should be around 485mg/i
If you did and still low power, does unplugging the maf restore power ?
EGR is sw off,not removed,forgot to mention.
Maf readings at idle are ok,it's about 485 mg when warm.
I wanted to disconnect maf,but someone told me that it won't do any good on a remaped car.

Could wastegate actuator have anything to do with this ? There are a lot of spikes in turbo graph

Last edited by Ryu85; 23-11-13 at 21:48.
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Egr is off in map id blank it anyway physically to be sure.
Those log results still look like a low reading both low end and high end
You have 1bar and only 440mg/i not 485mg/i
Top end i see 2100 mbar and only 800ish id expect 1050mg/i maybe and not 1200 as yours is on desired(maybe a symtom of remap )
The turbo pressure doesnt seem to look too far from desired.
Try a log with just revs, total fuel, act maf, act boost, vnt%
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Quote:
Originally Posted by sussexa View Post
Egr is off in map id blank it anyway physically to be sure.
Those log results still look like a low reading both low end and high end
You have 1bar and only 440mg/i not 485mg/i
Top end i see 2100 mbar and only 800ish id expect 1050mg/i maybe and not 1200 as yours is on desired(maybe a symtom of remap )
The turbo pressure doesnt seem to look too far from desired.
Try a log with just revs, total fuel, act maf, act boost, vnt%
Ok,I'll try to do another log tomorrow,thanks for help
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(Post Link) post #6 of 11 Old 24-11-13 Thread Starter
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log 24.11.xls
just made one mistake,clicked on vehicle speed,not engine speed...
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something is not right ,vnt% looks plausable
ive made your data into a graph with boost maf airflow and boost/maf
http://imageshack.com/a/img689/1008/l4vo.png
ive found with a sound system no leaks and good sensors the boost/maf = around 1.95-2.05
yours is all over the place and always above 2
still looks like a leak on the inlet after the maf sensor or low reading maf(but id expect a steadier error on boost/maf, your error is worse on boost peaks)
id be cleaning the map sensor incase its overreading
log again check boost / maf
remove and clean maf sensor again
log again check boost /maf
id blank the egr physically with a plate anyway to be sure
log again check boost /maf
this has only cost 3 odd for an egr blank
if still bad start looking for splits in pipe after maf ,turbo inlet pipe, oil separator, vapour trap , or breather pipe.
still nothing after that you may need a maf , what is the maf temperature like ? should be around ambient same as outside air temp on the move.
what is the map sensor temp reading like in cold weather we have now and driving similar to your last log id expext to see map temp around 12-15c higher than maf low load and maybe 20c or higher on a full throttle pull(around 2300mbar boost).
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(Post Link) post #8 of 11 Old 24-11-13 Thread Starter
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OK,I'll try all those things when I have more time.
I tried 3 different working maf sensors,readings always look about same,so it's probably not about maf sensor itself.
I'll have to check all pipes around turbo and intake...
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(Post Link) post #9 of 11 Old 20-12-13 Thread Starter
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Still waiting for egr blank plate to arrive,did another log with maf and map temperatures

log 20.12.xls

Weird thing is (it could have to do with not enough air problem) that car never gets 80 mg of fuel as in the map,it goes from 67-74 mg on full throttle,so desired boost doesn't go to 2400 mbar
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There are other limiters holding fuel back one is engine temp , you were only 60 odd degrees when you got full throttle so not full fuel anyway
In future logs get car up to temp 90deg
Try to hold a single gear from 2000revs to 4000revs and be full throttle, 4th best but whatever road conditions allow 3rd at least.
I dont like your inj correction values much, will look again after but saw some over 2 at higher revs.
Also when you log do least number of parameters and you get better refresh rate
Fit blank
Log, revs , act boost, act maf ,vnt%
Edit
Had another look
You still only have 450mg/i maf at idle
Your map temps look high for boost value be interesting to compare after egr blank fitted.
Inj 1 looks pretty bad at load, at idle looks ok, looks like 3 is trying to balance out, put a good injector cleaner in for next tank of fuel if i was you, possibly try contact cleaner in injector plugs also.
Fit egr plate , if values improve also do a relearn learned values wont do any harm.

Last edited by sussexa; 21-12-13 at 13:34.
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(Post Link) post #11 of 11 Old 22-12-13 Thread Starter
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I used Liqui Moly fuel system cleaner,did make injector correction better,but it didn't fix it completely. Should I buy one of this two:
http://www.ebay.com/itm/221268902372...84.m1438.l2649

http://www.ebay.com/itm/390291549519...84.m1438.l2649

And which one is better ?
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