From Audi 100 to urS4 in a week

[UrS4boy]

It will go lean, knock and the ecu will retard ignition and try to add more fuel, it will basically just hold back.

*DING*

Perfect diagnosis.

[hunker7]

It will go lean, knock and the ecu will retard ignition and try to add more fuel, it will basically just hold back.

Might be a daft question, but how does the engine know that's it "knock"?

You're blessed that it is as 'simple' as this, the car should be much improved once you resolve this.

Looking forward to your post after it's fixed.

I am now trying to figure out how to sort it tomorrow.

[UrS4boy]

G61/G66 Knock Sensor Information

Might be a daft question, but how does the engine know that's it "knock"?

Piezoelectric signal(s) from the G61 and G66 knock sensors

G61 and G66 Knock Sensor Info:

http://forums.quattroworld.com/s4s6/msgs/21047.phtml

[hunker7]

After some time managed to sort the fuel pipe the, wish me luck

I had a suspicion that compression is low (9 bar) because of bad starter motor, but I started the car on 4 cylinders and it's still low. So, I put some oil in the cylinder and compression went up by 2 bar. So I have no choice but to open up engine over summer and do the shells and rings, and hopefully upgrade rods as I am planning on many torques in next couple of years.

[hunker7]

Good news! (for once)

Runs much much better with the fuel line sorted now. Goes over 4k in 5th easy, but need someone who knows these cars to drive it, to tell me if it's running 100%, but it's good for now

Didn't like the way car was on idle, so got set of new coil to trial and it's much better, so I'll send the used ones back.

On top of that, got a quote from LongLife for exhaust, £450+VAT for decat, downpipe onwards. Sure they sent me a picture of the S6 Plus Spink was breaking

[UrS4boy]

Just to you know, when the 1.8t coil pack failures first started to show up, it was Bremi who had made the defective coils. If I remember correctly the VAG folks held Bremi's feet to the fire and made Bremi re-supply new coils to VAG at no cost to VAG. (But that is from memory, going back to 2004/05).

[hunker7]

Just to you know, when the 1.8t coil pack failures first started to show up, it was Bremi who had made the defective coils. If I remember correctly the VAG folks held Bremi's feet to the fire and made Bremi re-supply new coils to VAG at no cost to VAG. (But that is from memory, going back to 2004/05).

These are from V8, and also, i hope they learned from their mistakes

[hunker7]

Unfortunately car isn't still pulling well, the same issue with the revs not going over 5k. Car runs better generally but it's just when you get to high revs/speed.

MFTS seems to be playing up, as sometimes it works sometimes it doesn't, but MFTS isn't the one giving ECU the info is it? I've ordered a new lambda sensor, as I couldn't find any records of that being changed and car has done over 180 000 miles. Fuel consumption is bad too, regardless of how I drive 16mpg is the best I can do around town.

Can exhaust be blocked anywhere else apart from catalysts and middle silencer?

[ringbearer]

I had a chunk on cat stuck in the last bend of the muffler. Remove the exhaust from the cats back and test it out.

[hunker7]

So bought a compression tester today, just to try it out, I tested first two cylinders. What I did, I disconnected the 12v that go to coils, and removed one cylinder at the time, and when I turned the engine, in both cylinders I got a loud "pow" sort of noise. Could it be that valves won't shut properly and therefore the compression is so low and it won't run right?

[newsh]

Did you check the other cylinders?

With a plug out you should get all the pressure coming out the plug hole which will make quite a loud puffing noise untill you screw in the gauge.

[hunker7]

Did you check the other cyliders?

Did only first 2.

[newsh]

With a plug out you should get all the pressure coming out the plug hole which will make quite a loud puffing noise untill you screw in the gauge.

[newsh]

Disconnect the injectors too or you'll be blowing fuel out the open plug holes,

Best thing is remove the "motor" fuses from the fuse box, take all the plugs out and do it like that.

[hunker7]

With a plug out you should get all the pressure coming out the plug hole which will make quite a loud puffing noise untill you screw in the gauge.

The noise was with the gauge screwed in. And other cylinders had plugs in, but disconnected the ignition coils.

Disconnect the injectors too or you'll be blowing fuel out the open plug holes,

Best thing is remove the "motor" fuses from the fuse box, take all the plugs out and do it like that.

I don't have a fuse called "motor", at least I can't find one. But I will try doing that tomorrow possibly, get all the plugs out, disconnect coils/injectors.