Technical suggestion

[vcosmin]

I am struggling for 2 days to solve a problem, in my AAN engine.
The engines, stutter on high boost 1.2-1.4, and puff out some black smoke, when stutters, and sometimes when idling seems to be running in 4 pistons, not all time, but randomly.
So first thought was POS , i replaced them, no change, replace all spark plugs, the same, replaced coil pack, no change. I try to disconect injectors, 1 at time to see, if any change, seems to be not. Then i thought boost leak. I disconect MAF, and the car runned for a while on MAP i presume,still boosting ok to 1.4 but still the same problems. I disconect WG, the car was boosting only 0.4 - but no problems
Now i wonder, if the car has some boost leak, when i disconect the MAF, the engine took the amount of air which enter the engine, from another sensor right ? Manifold pressure or something like this ? if so, this will rule out any leak betwen MAF and Intake Manifold ? i checked, almost all the hoses i could check, but nothing. Opened to sugestion

[iain1067]

I would have a look at the wgfv, and also the hose that runs off the bottom of the turbo, they have tendency to crack where a smaller pipe is bonded onto it.

[iain1067]

have you also pulled the ecu codes and ran the cu output tests??? you need to take the hose off that i mentioned earlier. is your aan engine in an s4 or an s6???? the s6's use a plastic crossover pipe to the intercooler and if the jubille clips are not really tight they leak, consider also doing a leak test on the hoses.


Iain

[UrS4boy]

Before you rule out coils, you need to test them to see which one is the weak culprit. Have a read on this from the UrS4/S6 AudiWorld FAQ:

http://forums.audiworld.com/s4s6/msgs/149788.phtml

[vcosmin]

have you also pulled the ecu codes and ran the cu output tests??? you need to take the hose off that i mentioned earlier. is your aan engine in an s4 or an s6???? the s6's use a plastic crossover pipe to the intercooler and if the jubille clips are not really tight they leak, consider also doing a leak test on the hoses.


Iain

My Ebay USB Vag com cable, seems to not work, i will check that hose, my Car is S4, i thought, that is the stutter is still present when the Maf, is disconeccted the care will work based on MAP only, so it wil not be affected by any leaks ?

[vcosmin]

Before you rule out coils, you need to test them to see which one is the weak culprit. Have a read on this from the UrS4/S6 AudiWorld FAQ:

http://forums.audiworld.com/s4s6/msgs/149788.phtml

I changed all the parts, coils, wiring, Pos, Sparks, they were not new, but taked from another car, i hope that i was not so lucky to get both cars with same problems

[UrS4boy]

I changed all the parts, coils, wiring, Pos, Sparks, they were not new, but taked from another car, i hope that i was not so lucky to get both cars with same problems

Sorry mate but old is old. Could be fine but might be problematic. I think you have to start the missing and hesitation diagnostic from the beginning, checking everything.

[vcosmin]

Sorry mate but old is old. Could be fine but might be problematic. I think you have to start the missing and hesitation diagnostic from the beginning, checking everything.

You might be right, best to doublecheck everything, to bad, Ignition does not get error codes

[UrS4boy]

You might be right, best to doublecheck everything, to bad, Ignition does not get error codes

Correct. No part of the ignitions system: POS, Coils, boots or plugs throws a code when they fail. Complete pain in the "ash" but that is the way it is.

[Greg_S]

have you checked the quality of your earth for the coils?

[vcosmin]

have you checked the quality of your earth for the coils?

I have changed the wiring, the earth for spark plug is on Cylinger head ? then is checked.

I went to diagnose , since my cable seems to not be working.

so got the following codes

00553 - Air mass meter - sporadic - signal to low (it ok i think, as i disconected the MAF a couple of times, to see if it will make a difference)
00537 - Lamda control limit .... not reached,
01250 - Injector Cylinider 2 - N30 ( the same i disconected the connector to try and
see some difference)
01251 - etc for all injectors

At first i thought Lambda , so on the way back from diagnose i disconectet the sensor, and the Ecu will run in default value, a liitle rich, but no change the same stuttering (shacking ) etc.

Now 2 questions - If the Ecu runs without MAF, based on MAP it will not be affected by any leaks in the intake path, vacums etc ?
And if is a wastegate problem, meaning it happens on higher than 1 bar boost ? it will not be shown in any diagnostic, as is has no sensors right ?

I would like to afford to bye a complete new coil, pOs etc, set but i am not sure that is , and i dont like to lose money

PS i found a broken, "mushrom" i dont know the exact word, i will put a photo, with a sensor connector, but i thing is for oil reciluration or something.

[UrS4boy]

Your "mushroom", if it has an electrical connection, could be the N80 Evaporative Cannister control solenoid. If it's broken, you might have an air leak.

[S2central.net]

If its not an air leak, then I would say check the MAF next - there is info how on technical chapters at www.s2central.net - go into the MOtronic section and start with 3B where you'll get some good info.

The MAF test sequence is not very scientific, but will find a very bad MAF.

[vcosmin]

This is the piece broken, but i could not find it in ETKA, dont know what is it, if i disconect it , the car will not start. It seems that the part itself is not damaged, more is the conector.

[UrS4boy]

This is the piece broken, but i could not find it in ETKA, dont know what is it, if i disconect it , the car will not start. It seems that the part itself is not damaged, more is the conector.

LOL. Yep. What you have there is your Hall sender in a Tuna Can(tm) vestigial distributor or as you called it "mushroom" (I prefer Tuna Can). With it disconnected, the ECU (computer) will never start the car because it doesn't know what the spark timing needs to be. If the Hall sender is good you can probably just replace the plastic connector. I'll see if I can find the part number.