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What does this mean??

Hi.

I'm noob when it comes the diesel engines... soooo, I'm looking at these numbers and have no idea whether they're wrong or not.

The car is a '06 159 2.4 Q-Tronic. DPF and EGR had been removed before I bought it, and the torque limiters are higher than stock, so I assume it was remapped as well.
I'm chasing a random shaky idle, occasional diesel smell and of course high(ish) fuel consumption.
I made some logs..

On idle cyl# 2 & 3 have negative correction numbers. No idea if it is good or not... I should check the injector coding?
http://i74.photobucket.com/albums/i2...psormk3baq.jpg

Still on idle, fuel quantity. This seems odd to me. As you can see the desired fuel qty jumps around for no obvious reason (to me), the actual qty stays flat (as it seems logical to me)..... shoddy remap? Desired air qty is flat, you will see that on the next chart...
http://i74.photobucket.com/albums/i2...pssttgz2ji.jpg

Again, car is idling. Desired air gty is nice and flat 229,5mg/i. However, the actual air qty is about 40% more. This is worrying to me. EGR is blanked and coded out.
http://i74.photobucket.com/albums/i2...psulefq182.jpg

I did a log for a long drive, actual air qty is 54% more than the desired in average. Max difference is ~130% more. It is normal cruising condition around 1300-1500 rpm and a steady 10% gas pedal position.


My conclusion is:
-Diesel smell is probably leaky swirl flaps, because I can only smell it in the cabin or in the engine bay.
-in normal cruising condition, it runs richer than the desired fuel qty, but I can't relate it to actual air qty. Sometimes the air is also more sometimes it is less ... confused....

I know there are some prettttty clever people on board, could You please help me understand what is happening?

'06 159 2.4 JTDm Qtronic.
'08 Mito 1.4 Tjet 155.
'97 Volvo 940 Estate.

Last edited by Nari; 27-04-15 at 10:58.
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I'd make sure your sensors are all optimum, take the MAP out and give it a good clean, and check the running, then try unplugging the MAF sensor, see if that effects it, very simple things to do that can make a difference that they'll check first if you take to a garage.


Any spelling/ grammatical errors are purely there to annoy!
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(Post Link) post #3 of 6 Old 29-04-15 Thread Starter
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Quote:
Originally Posted by giblets46 View Post
I'd make sure your sensors are all optimum, take the MAP out and give it a good clean, and check the running, then try unplugging the MAF sensor, see if that effects it, very simple things to do that can make a difference that they'll check first if you take to a garage.


Any spelling/ grammatical errors are purely there to annoy!
thanks!

Cleaned the MAP few weeks ago, that should be good.
Haven't tried unplugging the MAF, yet. I'll give it a go!
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the sum of idlecorrection values is always zero, but this might not always show up as such because of transmission lag.

desired fuel quantity will go up when rpm drops, and fall when revs rise. afterall, idle is a state of rpm regulation.

check air quantity together with turbo pressure. if egr is disabled, the car is likely remapped. desired air quantity seems low to me because the ecu presumably wants a lot of egr. with no egr, I'd expect about 500mg/inj without boost.
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(Post Link) post #5 of 6 Old 12-05-15 Thread Starter
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Quote:
Originally Posted by Cuore_Sportivo_155 View Post
desired fuel quantity will go up when rpm drops, and fall when revs rise. afterall, idle is a state of rpm regulation.
see, new info here... I had been assuming, the idle is regulated by an idle valve (as in my volvo).
So, idle is regulated by the fuel qty.
Great. Desired qty is oscillating because of rpm regulation, that is clear. Than why is the actual qty a "straight" line? It should oscillate accordingly, shouldn't it?
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