G28 sensor issues.

[Stefen]

We are trying to restart the buggy after swapping the engine for a forged one. The ecu doesn't seem to be reading the G28 sensor and reports a variety of reasons. Perhaps someone can offer a few suggestions?

[Error404]

You always get this fault code without the engine running, as the sensor has no trigger with the flywheel stationary.

Odd that you are getting different varieties

[madpugger]

That is a strange one for sure, are there the correct number of teeth on the flywheel?

Not likely to be this in this case since the starter is the other side of the engine, but we recently had a similar issue with a TD5 Defender, which turned out to be a failing starter (which worked perfectly in as far as it turned the engine over at a normal speed) that was throwing out weird electro-magnetic signals effecting the engine speed sensor. I wouldn't have believed it if I didn't see the result from a new starter! :O

[madpugger]

You always get this fault code without the engine running, as the sensor has no trigger with the flywheel stationary.

Odd that you are getting different varieties

You do get the "no signal" code while the engine is not running, but the other one I'd not expect to see unless there is an issue...

[Stefen]

We are using a different flywheel which came with the new engine, so it's something that we haven't thought of, thanks for that. I think it could be a solid one, rather than a dual mass.

[madpugger]

It is possible then that the number of teeth is different, a tooth is missing, or the trigger has fallen off, although the trigger having fallen off shouldn't affect the speed sensor (directly)

[Stefen]

The trigger is still on the back of the flywheel. I'll have the teeth counted to rule that out.

[Stefen]

135 teeth present and intact.

[UrS4boy]

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

It is possible then that the number of teeth is different, a tooth is missing, or the trigger has fallen off, although the trigger having fallen off shouldn't affect the speed sensor (directly)

You might be confusing the G4 crank position sensor pin ("trigger") with what the G28 is looking for. The G28 just counts teeth.







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

http://forums.quattroworld.com/s4s6/msgs/20986.phtml

[newsh]

Are the G4 and G28 plugs swapped?

[Stefen]

Good question. The colours of the connectors match the corresponding connector on the loom. Two grey and two black IIRC.

[UrS4boy]

Good question. The colours of the connectors match the corresponding connector on the loom. Two grey and two black IIRC.

It wouldn't even start if you didn't have them connected properly (and you would get a G4 error too)

AAN



S2/RS2

[Stefen]

Thanks for the pics. The engine is in our buggy so the wring is a little different. See thread - http://www.s2forum.com/forum/showthr...t=53745&page=2

[UrS4boy]

Thanks for the pics. The engine is in our buggy so the wring is a little different. See thread - http://www.s2forum.com/forum /showth...t=53745&page=2

I went through most of the thread. I get the buggy thing now. Did I miss a photo of the AAN connector rack (which you might have used??)

[Stefen]

Just showing that the application is a little different from norm and the wiring and connectors aren't in the OEM positions. There's no wiring specific picture to see, that other thread is a couple of years old.

The ecu needs G28 Engine Speed, G40 Cam Position Sensor and the G4 Crank Position sensor to start. Perhaps it's an earth issue as when strange things happen, that's often the culprit. We'll check the ECU earth wire and engine earth strap.

BTW - This engine has not been started since was rebuilt, so there is another unknown to factor in.