engine running lumpy

[pasbogdan]

Today i made conversion to 1.8t coils.
Started the car and it was very lumpy.It sounds exactly some rally cars at idle..All cylinders fire,can see that if i stabilize it to 2500 rpm. Today no access to vag com so i started changing parts.Maf,tps,icv.Did a boost leak and found nothing up to 1 bar.Only few little bubbles at isv.Put back the stock coil pack.The same.
Car run perfect few days ago.Was left with + connection to battery removed and coil conversion was all it was done to it.
Afr gauge shows approx 15:1 and very lean changing 1 or 2 times a second according to engine lumpy behavior.
If i stabilize it at 2500 rpm afr fluctuates 14-15 and after 10 seconds starts to be lumpy again.
Something wrong with ecu because of the coils?
That lean afr could be spark cut or fuel cut.

[ManiacuV6]

Sounds funny but is it possible that you touched a vacuum hose and it got off from intake manifold or that area ?

[pasbogdan]

I was thinking at that also.That is why i made a boost leak.But no vacuum could cause it to run so lumpy..

http://www.youtube.com/watch?v=xZWkAzR-EXc&feature=youtu.be

[Colesy]

Is everything plugged back in, has a fuse blown? One fuse covers the ISV and MAF I think, made my S2 run as lumpy as hell when it had blown.

[UrS4boy]

Is everything plugged back in, has a fuse blown? One fuse covers the ISV and MAF I think, made my S2 run as lumpy as hell when it had blown.

Not saying that there isn't a fuse blown but I think the ABY is similar to the 3B and with the 3B, the MAF is on the same fuse that powers the injectors (once the engine has started) (S28) and the ISV is on the same fuse (S24) as the N75 WGFV and the N80 Evap Emissions control valve.

[bartolomeus]

I like it better like this. Rally'alike

[UrS4boy]

Today i made conversion to 1.8t coils.

Did you use new or used 1.8t coils? Used coils could be weak, dying or barely alive. I know your pricing is not as good as ours on those coil packs, i.e. $15 for the red 4.2L V8 coilpacks, but starting with anything less than new coilpacks is asking for issues.

[bartolomeus]

Brand new coils. OEM.

[UrS4boy]

Brand new coils. OEM.

Okay. What about the grounds for the new 1.8t coilpack harness? 1 or 2? Are they connected to a good ground on the intake manifold and/or cam cover?

Is your MAF plug clean and all the pins in fully in their place?

Did you put in new plugs? Gap? Are they tight?

Injector connections? Any broken wires on the injector harness (at the injector)?

[Pirvu Eugen]

Is running lumpy from the beginning? If is running lumpy from the beginning i suggest the fuel pressure or injectors....should stabilize a little bit after the engine is hot. Or the lambda is dead....and before removing the battery had the adaptive mixture learned for the old lambda values...just a though.
Regards!

[rafa89]

Looks like MAF or ISV... Maybe a blown fuse?

[bartolomeus]

PASBOGDAN:

As I said before in the beginning the car ran perfectly before installing the new 1.8t coilpacks. And I've tried putting back the old coil packs and it still doesn't work.
Two grounds mounted in the harness, one ground for internal POS, one ground mounted in the cam cover.
Good ground checked.
As I said before I already tried another MAF on the car.
I tried another ISV and TPS.

Does anybody know where other fuses (beside the engine bay) may be?

[pasbogdan]

Me this time.Ur s4 has aditional fuses near ecu.What about coupe chasis?

[UrS4boy]

Me this time. Urs4 has aditional fuses near ecu. What about coupe chassis?

I don't think so (could be wrong, if so, somebody correct me with photos/diagrams (please)).

Power to the ECU = S27 = front row of the box, under the Motor/Moteur cover
Fuel pump S13 = in the box
Lambda Probe = S25 or S26 = front row of the box.
Injectors and MAF = S28 = front row of the box under the Motor/Moteur cover
WGFV, ISV and N80 = S24 = front row of the box



Note this one shows 25 and 26 empty and 23 and 24 full. Probably actually S24 and S25/26

[UrS4boy]

Did you put in new plugs? Gap? Are they tight?

Injector connections? Any broken wires on the injector harness (at the injector)?

bartolomeus: You didn't answer these two (above).

On my home forum, quattroworld, the other day a new UrS4 owner who was not familiar with the AAN's quirks was complaining about the engine not running properly, especially under boost. We went through all the usual possibilities, e.g. coils, POSs, coil-to-plug boots, plugs, etc. He found a weak coil and swapped in a supposedly good coil. Things improved but were not 100%. Finally he found the issue: one of the two wires to injector no. 5 was almost cut through and only a few strands of wire were intact. (Why that would happen I have NO idea ). Fixed the wire and now the engine runs properly.