wiring tape

As mentioned, non-sticky vinyl tape to stay original. If rewiring the whole engine bay, and you don't care to be original, I used smooth PVC from SPC Technology. I bought several sized rolls off ebay. That is factory in my 80's Mercedes's. At junctions, I wrap w/ self-fusing silicone tape. Others use split loom. It is bulkier and harder to clean gunk off, but the only option if connectors are already on (other than tape).