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Hello, I recently picked up a non-running ‘83 944 and in diagnosing electrical issues decided to replace the engine wiring harness since mine had some damaged portions.
Does anybody know if early cars use the intake manifold as a grounding point instead of the bell housing? It looks like a PO might have connected the harness grounds near the speed/ref sensors to the manifold and firewall instead of the locations on the bell housing.
I wasn’t able to find a clear picture or video detailing how the harness is supposed to be grounded here. TIA!
The first photo shows what looks like a snipped ground connection on the bell
housing. The second photo is how my current harness is connected to ground on the manifold and firewall.
The heavy braided ground cable is as shown above. But there are at least two more lesser (maybe 12 ga) ground wires that attach up around the intake manifold. If you have 2 wires in that area (near the reference sensors), as a general statement, you might want to attach one to the cylinder head and the other to the intake manifold. My cars are long gone but hopefully someone will be able to post a photograph of how these are arranged.
Firewall to bell housing. Here's my unmolested early car from passenger side....
Thanks for the clear picture of that. That definitely helps clear some things up. Where do the two grounds from the harness next to that braided cable end up? It seems that the larger of the two gets connected with the ground strap?
Originally Posted by harveyf
The heavy braided ground cable is as shown above. But there are at least two more lesser (maybe 12 ga) ground wires that attach up around the intake manifold. If you have 2 wires in that area (near the reference sensors), as a general statement, you might want to attach one to the cylinder head and the other to the intake manifold. My cars are long gone but hopefully someone will be able to post a photograph of how these are arranged.
Yeah I do have the two ground wires which from my understanding are a high and low power ground for injectors/sensors. Thanks for the input that might be the way to go.
Cleaning grounds on 944s and 928s is a pretty common maintenance item when you are getting random issues. You can use the Search function here but more generally, just Google "Where are the ground points on a Porsche 944". You might need to narrow it down and add "early 944".
Also, as a general statement, bookmark Clarks-Garage.com, which contains a wealth of DYI info for the 944.
07-28-2024 | 10:45 PM
Early 944 engine harness grounds
