Help with chart reading and nozzles please

[mikeyibiza]

Hi all, I have just replaced the nozzles on my 51 plate ibiza 110 tdi sport with .216's and i was expecting more, I have adjusted the egr through vag com. the car is a little pokier but not what i was expecting (ive done nozzle changes before and noticed alot more of a difference) there is no smoke, I have checked the injector balance and there all within limits, the IQ is fine 3.4 the turbo is fine (15psi all the way through) and I have done a log of the maf readings but could do with a little help to see if the maf is all good?

Engine speed MAF (specified) MAF (actual) EGR duty cycle
1071 410 465 Apr-84
1092 445 460 %
1113 635 475 84.5
1155 850 525 77.3
1239 850 580 64.1
1281 850 645 4.8
1365 850 705 4.8
1470 850 805 4.8
1575 850 895 4.8
1701 850 965 4.8
1806 850 965 4.8
1932 850 930 4.8
2058 850 910 4.8
2163 850 905 4.8
2289 850 890 4.8
2394 850 870 4.8
2478 850 885 4.8
2583 850 900 4.8
2688 850 875 4.8
2793 850 855 4.8
2877 850 830 4.8
2982 850 825 4.8
3087 850 820 4.8
3171 850 770 4.8
3255 850 750 4.8
3339 850 745 4.8
3423 850 750 4.8
3507 850 750 4.8
3570 850 755 4.8
3633 850 750 4.8
3717 850 750 4.8
3780 850 750 4.8
3822 850 740 4.8
3885 850 740 4.8
3948 850 740 4.8
3990 850 740 4.8
4053 850 735 4.8
4116 850 730 4.8
4158 850 715 4.8


please can anyone give ideas to if the maf looks good or any ideas

Cheers

 

[sssstew]

MAF looks like its tailing off to me, probably could do with replacement.


for reference
http://www.ross-tech.com/vag-com/cars/tdi.html

 

[muddyboots]

What sort of run did you log the MAF readings over ?

 

[mikeyibiza]

It was a run in 4th gear on at normal operating temps. I read somewhere that having the egr reduced should mean higher numbers? which would mean its more out that it looks?

cheers

 

[muddyboots]

I think the EGR only operates on zero or light throttle though, so on a full-power run it shouldn't have any effect.

 

[mikeyibiza]

cool, I've brought the IQ down to around 2 and it doesn't smoke at all, just wondering if that could be the maf? if the lift needle injector wasn't working would it throw a code?

cheers

 

[mikeyibiza]

Please help may have a big problem??

I done some more logs and I found group B 008, it only has 3 injectors named but one of them is definitely less than the others, Is this what its supposed to be or what injector would it be? please help I dont want to damage anything



'008
Engine speed Inj qty Inj qty Inj qty
? ? ?
/min mg/str mg/str mg/str
1302 10.6 36 31.6
1491 16.2 38.6 34.8
1575 9 39.8 33
1932 45 43.4 43.8
2814 44.2 41.8 43.8
2898 0 41.8 30.8
2457 0 42.2 30.6
2205 3.6 42.6 32.2
2016 3.6 43 31.2
1806 6 42.6 33.6
1785 12.6 42.2 34.6
1890 15.6 43.4 36
1974 34 43.2 40
2709 44.2 42 44.2
3066 0 41.6 29.8
2541 0 42.2 30
1995 3.2 43 26.6
1827 9.6 42.8 33.2
1785 13.6 42.2 34.6
1869 18.4 43.2 33
1953 26.4 43.2 36.6
2415 24.6 42.2 43.4
2310 5.2 42.4 31.2
2100 8.8 42.8 31
1911 8.2 43.4 34.2
1491 0 39 28.2
1029 0 32.4 27.2
1113 13.2 33.4 29.6
1197 5.6 34.2 26.8
63 15.2 0 34
882 17.2 31 26.6
2142 44.8 42.6 44.2
2142 9.6 42.6 31.6
1932 10.8 43.2 31.6
1848 15.4 43 34.8
1890 20.8 43.4 35.8
1932 12.6 43.2 30.8
1890 24.8 43.4 32
2310 39.6 42.4 44.4
2961 44 41.8 43.6
3507 11 41 40.6
3150 0 41.6 29.6
2478 0 42.2 29.2
1848 0 43 27.8
1512 4.2 39 29.6
1344 8 36.6 31.6
1281 9.6 35.6 30.8
1302 12 35.8 31.4
1365 7.8 36.8 31.4
966 12.6 31.6 27.6
903 0 31.2 26.2
903 0 31.2 25.2
1008 11 31.8 28.8
924 0 31.4 26.6
903 0 31.2 25.8
987 14 31.8 27.8
1533 13.4 39.2 32
1092 6.4 32.8 30
1344 5.6 36.4 30
1407 0 37.6 29.4
1428 1 37.8 28.8
1575 1.6 40 28.6
1575 0 40 28.2
1533 0.4 39.2 28.2
1470 0 38.6 28.4

many thanks

Mike

 

[sssstew]

I think the EGR only operates on zero or light throttle though, so on a full-power run it shouldn't have any effect.

correct

 

[muddyboots]

I done some more logs and I found group B 008, it only has 3 injectors named but one of them is definitely less than the others, Is this what its supposed to be or what injector would it be? please help I dont want to damage anything

I think you're misunderstanding what that block is showing you. It's nothing to do with individual injectors.

The 3 injection quantities it shows are:

1) injection qty requested by driver (ie how far you're pressing the accelerator)
2) injection qty limit for current RPM (ie the max amount of fuel your ECU map will ever allow to be injected at the current engine speed)
3) injection qty limit for current MAF reading (ie how much fuel your ECU map will ever allow to be injected based on the amount of air going into the engine - as reported by the MAF).

The lowest of the 3 values "wins" and determines the injection quantity used.

If that makes sense....

 

[mikeyibiza]

cool, that does make sense, so there is no issue there then, Im just baffled to why there is no smoke what so ever, on .216 nozzles and 15 psi boost? thought it would be guffing it out

cheers

 

[muddyboots]

cool, that does make sense, so there is no issue there then, Im just baffled to why there is no smoke what so ever, on .216 nozzles and 15 psi boost? thought it would be guffing it out

cheers

Well, like Stew says, looks like your MAF readings could be tailing off a bit.
In which case, that would be what's limiting the amount of fuel the ECU is injecting.

Would be interesting to see another log of block 008, but over a full-power 4th gear run up through the rev range (like you did with the MAF).
If the last column (ie IQ limit due to MAF) stays the lowest of the 3 columns, then it's the MAF readings that are limiting your fuelling.

I know of 1 or 2 people who have electrically bypassed the MAF with a "diode mod", which means the MAF is always reporting maximum airflow, and so the only limiting factors then become the IQ requested by driver, or IQ based on RPM (ie your ECU map)....

Might be worth changing your MAF anyway, if your finances allow.