[Mk2] [NA] No speed signel to ECU after fitting turbo engine to Rev 1 NA

[bobhatton]

My son has just fitted a Rev2 turbo engine to a Rev1 NA and all is working great but no speed signel to the ECU.

I am sure I have seen this problem before but do not know the fix, can anyone help please?

[badgerbob]

rev 1's run off a mechanical speedo drive as opposed to electric, has this been taken into consideration?

[bobhatton]

rev 1's run off a mechanical speedo drive as opposed to electric, has this been taken into consideration?

Yes, there is a signel that comes back from the speedo that gives an input to the ECU but not getting that at the moment

[Peter Gidden]

Check 4th ECU plug and ECU pin for violet/white return wire.

[bobhatton]

Check 4th ECU plug and ECU pin for violet/white return wire.

Peter

The ecu, engine loom and left hand body loom are all rev 2 so it will have the wire as it worked ok in the rev 2 car.

The NA car the engine has gone into has no power steering so would the speedo have the output to feed the steering and the ECU?

[Peter Gidden]

Bob

I'm sure, IIRC, the violet/white wire branches off the body loom at the bulkhead behind passenger seat.

Humour me, and check continuity between violet/white wire at instrument cluster plug, and violet/white wire at ECU plug.

[bobhatton]

Car is away having body work done, will check when it comes back.
I do know the only wiring coming from the body loom and into the plug behind the passenger seat is two wires, the fuel pump is one, will check more when the car is back.