Oldopels Posted September 17, 2021 Share Posted September 17, 2021 Can anyone tell me which is the signal wire on a P38 4.6? I have two wires to choose from Pink & Black or Black & Yellow. Thanks in advance for your assistance. 👍 Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 17, 2021 Share Posted September 17, 2021 Which year? Gems or Thor? Quote Link to comment Share on other sites More sharing options...
Oldopels Posted September 17, 2021 Author Share Posted September 17, 2021 It’s a 2001 Gems engine built by RPI Engineering. Thanks for your help @elbekko. Quote Link to comment Share on other sites More sharing options...
Escape Posted September 17, 2021 Share Posted September 17, 2021 PB and BY are the 2 signal wires on the sensor in a GEMS. The Bosch has a separate 3rd B wire for earth. 1 Quote Link to comment Share on other sites More sharing options...
Oldopels Posted September 18, 2021 Author Share Posted September 18, 2021 Does anyone know which is the signal wire? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 18, 2021 Share Posted September 18, 2021 It is a variable reluctance sensor -they use both wires. 1 Quote Link to comment Share on other sites More sharing options...
Oldopels Posted September 19, 2021 Author Share Posted September 19, 2021 Thanks guys. So it won’t damage the ecu if I connect them up the wrong way round? I thought it would send the opposite message 1:36 not 36:1 🤷♂️ Also are there different cps’s for manual and automatic. I’ve changed the flywheel and the sensor seems to be too far away from the trigger wheel. If they are different does any one have a part number for the manual one? Thanks. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 19, 2021 Share Posted September 19, 2021 If the wrong way round, it may well just not work, but no damage to be done. 1 Quote Link to comment Share on other sites More sharing options...
Escape Posted September 19, 2021 Share Posted September 19, 2021 There are different sensors for manual and automatic because of the location of the tooth wheel. But that can be solved by playing around with the spacers as well. Also a difference between early and later GEMS, early ones have the connector high up near the coils and a short wire on the sensor, later ones have a longer loom with the connector directly at the sensor. I think the connector is the same, so interchangeable if you adjust the wire length in the loom. Please tell us a bit more about your project, that will help give the correct info. Are you using the standard GEMS ECU or something aftermarket like MegaSquirt? Also, there's no such thing as a 2001 GEMS, they were replaced by the Bosch ECM in 1999. Filip 1 Quote Link to comment Share on other sites More sharing options...
Oldopels Posted September 19, 2021 Author Share Posted September 19, 2021 That’s good news @Bowie69. Great advice @Escape and I’ve found a sensor for a manual 😁. The engine is in an Opel Manta and being managed by a stand alone Emerald ecu. I don’t know the full history of the engine but RPI told me that their records show the engine was built in 2001. Quote Link to comment Share on other sites More sharing options...
Escape Posted September 20, 2021 Share Posted September 20, 2021 That sounds like a fun project! 😎 Everybody likes pictures... It is possible that the engineblock was cast in 2001, the GEMS management (and 'brick' intake etc) was only used up to '99 by Land Rover, but lasted longer with TVR etc as they never made the transition to Bosch management and the 'banana' manifolds. I have a Megasquirt running an engine with a GEMS flywheel (though not yet in the car...) and standard sensor, so the Emerald should cope as well. Makes for a tidy install without the addition of a toothed wheel at the front. Filip Quote Link to comment Share on other sites More sharing options...
Oldopels Posted September 20, 2021 Author Share Posted September 20, 2021 Sounds like we are going for a similar set up @Escape. I’ve got a manual flywheel now so I can continue to use my LT77 box and have removed the spacer as you suggested from the cps and see good rpm when cranking the engine. I’ll post some photos tonight. 😁 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 21, 2021 Share Posted September 21, 2021 As others have said, it's a VR sensor (basically just a magnetic coil) so it generates an AC voltage, if you reverse the wires nothing bad happens but it cocks up the "missing tooth" detection in the ECU and it will likely not fire up, or run really weird (RPM signal jumping around). If you're unsure, and Emerald don't give any guidance, I'd wire it up in such a way that you can remove & swap the wires over / re-pin the connector if needed. Quote Link to comment Share on other sites More sharing options...
Oldopels Posted October 11, 2021 Author Share Posted October 11, 2021 She runs! Thanks very much for your help @elbekko @Escape @Bowie69 @FridgeFreezer https://share.icloud.com/photos/08FI85Fg2KSlXJLLxUNWLBnLg#Eastleigh_-_Fair_Oak 3 Quote Link to comment Share on other sites More sharing options...
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