Rough idle, no pulse on injectors 4 and 8.

[RMReid]

we have a 2004 Porsche Cayenne S (4.5 V8 naturally aspirated)in work, it had shot a piston through the block so required a new engine.

New engine has been fitted, all ancillaries back on, primed the oil pump and fired her up without issue but theres a bad misfire.

Using the Snapon Verus we are getting;

P0208: Injector circuit/open cylinder 8

P0204: Injector circuit/open cylinder 4

P1092 Manufacturer specific code

P0358 Ignition coil 'H' circuit open

P0354 Ignition coil 'D' circuit open.

there is no pulse going to injectors 4 or 8 but as much as the wiring as we can see and its ok, my next thought was that if it wasn't sparking at the plug then would it shut down injectors?

any help at all would be much appreciated, and if any one has an ECU pin diagram it would be helpful!

thanks!

[deilenberger]

Almost all modern injection systems will turn off the injector if a misfire is detected. My WAG - you either have bad coils on 4 and 8 (you can determine that by moving them around to different cylinders and see if the fault follows the coil..) or - some bad wiring going to them. The injector/open-circuit message seems definitive..

[RMReid]

Almost all modern injection systems will turn off the injector if a misfire is detected. My WAG - you either have bad coils on 4 and 8 (you can determine that by moving them around to different cylinders and see if the fault follows the coil..) or - some bad wiring going to them. The injector/open-circuit message seems definitive..

that what I thought, we've moved coils and spark plugs but the misfire is still present. guess its time to check the wiring. and ideas on pin outs from the ECU to be checking?

thanks for the reply mate.