AAN swamp and S2 speedo false information.

[Kiku]

Originaly was 2.3 20v and now swamped AAN engine. Electrical side is allso AAN made to work on coupe. Gearbox is 01A and speedo is from S2 and everything is working aux dials, oil/engine etc warnings, rews, speedo but somehow rews are far from right. Standing still engine rews are 1k on clocks actual with computer checked are 780 as it should be. Driving 110km/h rew's should be 3k but on clocks they are 4k. Can someone tell me whats the problem. Can somehow the missing extra engine speed signal from AAN ECU for cruise or clima make this big difference?

[UrS4boy]

Crank Position (G4) and Engine Speed Sensor (G28) Info - Function , Location and PNs

Can somehow the missing extra engine speed signal from AAN ECU for cruise or clima make this big difference?

No.

I know it is a language issue but you talk about "Speedo" (e.g. kilometres/hour) and then "rews" (which I think you mean "reVs", as in revolutions per minute (RPM) in the same breath. I can't tell which one you actually need the help on.

Guessing that it is revoutions per minute that is the issue, the RPM signal for an AAN in an UrS4/S6 is generated by the G28 engine speed sensor which effectively counts the flywheel ringgear teeth as they go by the sensor. It expects 132 teeth on the ring gear so if you swapped to some other flywheel, that could be the issue.

At the other end, the tachometer that displays the RPM reading might not be compatible with the AAN flywheel (if that is what you are running).

G28 engine speed sensor info: http://forums.quattroworld.com/s4s6/msgs/20986.phtml

[Kiku]

Your right. I ment REV's not REW's. And by speedo i ment speedomeeter dials could'nt find the right word in my head.
But jes rev's are far bay right and flywheel is 7A, clutch is completely AAN with strengthened clutch disc. So if im right i would have to switch to 7A g28 sensor if the teeth are not the same as AAN flywheel but if im right sensor on 7A and AAN are not exactly the same there was something different between them.

[elaw]

It sounds like your tachometer is configured for a 4-cylinder engine - if that's the case, it'll read about 25% high when fed the tach signal from a 5-cylinder.

I don't remember the details but there's a pin on the tach module itself that controls whether it reads 4- or 5-cylinder RPM. I think that connection is brought out either to a jumper on the instrument cluster or a pin in the cluster harness.

If I have time, I'll try to look in the book tonight and find out more.

[elaw]

I was right! The yellow connector on the back of the instrument cluster (aka "T26"), pin 23, is grounded for a 5-cylinder car (via a brown/black wire from T10a/6) and left open for a 4-cylinder car. If that pin is open with a 5-cylinder engine, the tach will read high as I describe above.

[UrS4boy]

Way to be a lert there elaw.

What is confusing to me is a 2.3L 20V engine is a five cylinder 7A.

Originaly was 2.3 20v and now swapped AAN engine.

[elaw]

Yeah that seems odd to me too. But it could be a bad connection, or that it lost its ground due to other work done on the car.

[GazzaG60]

does seem strange. are they for sure s2 clocks. or refaced 4 pot items.

is the autocheck o 4 pot clocks at all? wasn't on mine or in the cabs ive seen.

them wires are thin so maybe a break. to stop the light, pas, washer warnings as i dont have the sensors i did the grounds further away from the clocks to avoid issues.

[Kiku]

Definetly S2 clocks.

[Kiku]

It's been a while but the problem is solved. Since the whole engine electric came from s4 aan then t10(black) plug is new and t10/5 pin was left open so now its 0V and tach reads as it's supposed to. BIG BIG thanks elaw!!!