Cleaning up wiring post EFI conversion, questions regarding certain wiring

[opethmike]

Need to know what the following do:

Lambda switch in the y-pipe - only needed for K-Jet, right?
Idle speed thermister - only needed for the stock idle system, right?

What circuits do the two small ground wires that are normally connected to the K-Jet intake manifold provide ground for?

[stevedmc]

Moderation never ceases to amaze me. I go outside to take some pictures just for Mike and my words are wiped away like the never existed.

Anyway, here are a few pictures of what my bulkhead connectors look like after I ditched all of the K-Jet wiring.

I don't have any of the diagrams (old forum) but maybe these pictures will help. You might be able to get some detailed diagrams from Bill if you ask him.

[opethmike]

Cool, thanks! Those pictures will certainly help.

[DMCMW Dave]

Need to know what the following do:

Lambda switch in the y-pipe - only needed for K-Jet, right?
Idle speed thermister - only needed for the stock idle system, right?

What circuits do the two small ground wires that are normally connected to the K-Jet intake manifold provide ground for?

Lambda switch enriches the FV setting when cold, so if you are not using the Lambda ECU it isn't used anywhere else.

Idle speed thermistor bumps the idle when very cold, if you ar not using the OE idle speed computer to run the idle motor, it isn't used anywhere else.

There are more than two ground wires on the OE intake, so you probably need to trace them to see what they do although I can't imagine that any of them are doing anything useful any more. Have you ditched the full throttle microswitch, and idle microswitches? The "red" ground on the passenger side is the Lambda ECU ground reference for the O2 sensor so you can probably live without it - unless you used it in the new installation.

[opethmike]

Lambda switch enriches the FV setting when cold, so if you are not using the Lambda ECU it isn't used anywhere else.

Idle speed thermistor bumps the idle when very cold, if you ar not using the OE idle speed computer to run the idle motor, it isn't used anywhere else.

There are more than two ground wires on the OE intake, so you probably need to trace them to see what they do although I can't imagine that any of them are doing anything useful any more. Have you ditched the full throttle microswitch, and idle microswitches? The "red" ground on the passenger side is the Lambda ECU ground reference for the O2 sensor so you can probably live without it - unless you used it in the new installation.

Awesome, thanks Dave. I am currently using the OE idle speed motor, but will be getting rid of it for a modern IAC.

I did indeed ditch the full throttle microswitch and idle microswitch. Not using the stock O2 setup either.

Sounds like I'm going to be able to get rid of a lot of stuff. I'm aiming to be able to get rid of the idle ECU and the lambda ECU, plus clean up the jungle of unused wiring in my engine bay.

[Spittybug]

http://dmctalk.org/showthread.php?2056-Hardware-amp-Integration&p=44560&viewfull=1#post44560

Pictures of the new harnesses with the only necessary connectors on it.

[opethmike]

VERY nice looking harness. Planning on making more? I'd love to buy one; I could just remove the old harness instead of having to unwrap, remove wires, re-wrap.

I noticed in the list there that you only listed one oil sensor. There are two; you're wiring for both, right?

[stevedmc]

I noticed in the list there that you only listed one oil sensor. There are two; you're wiring for both, right?

Just unwrap the harness and cut off whatever wires you aren't using anymore. I'm pretty sure I used Bill's diagram, but honestly, you don't need it since its obvious what you aren't using anymore. Just cut away and be sure to leave a little wire extending from the connectors just in case.

Everything worked fine for me afterwards. When I get around to it I'm going to trim the rest of the wire.

Here is a quesiton. Are you still able to do the starter trick we carb guys do on your EFI setups? We basically save the wire that ran to the cold start valve (I think) and cover the end of it.

If you are ever in a bind and have trouble starting you can tap this wire to your postive terminal to provide power directly to the starter. You should be able to see the wire in one of my pictures and I think Farrar has a youtube video of him demonstrating it.

This would be a nice mod if you have a manual transmission and if you don't use that wire on an EFI setup.

[opethmike]

I actually don't have that trick set up at all. I really like the sound of it, and I appreciate the suggestion Steve, thank you!

I will be able to use that wire; the cold start valve is long gone.

I had planned on going your suggested route regarding the wiring harness, but if Owen is willing to make and sell another one of his harnesses, that would be great as it looks much nicer.

[stevedmc]

I actually don't have that trick set up at all. I really like the sound of it, and I appreciate the suggestion Steve, thank you!

I will be able to use that wire; the cold start valve is long gone.

Glad to be of help. I searched Farrar's Youtube channel and can't find the video. I know he made a video of it in the past. Anyway, it might be a good idea to double check with him or Bill to make sure it is the CSV wire. I can take a picture of it for you this evening if you can wait.

Also, be sure your car is a manual and in neutral before you bump the starter. I don't want to get blamed for someone loosing their legs.



I had planned on going your suggested route regarding the wiring harness, but if Owen is willing to make and sell another one of his harnesses, that would be great as it looks much nicer.



White trash like myself prefer to just use electrical tape. Carefully slice open the existing harness with a razor blade. Remove what you don't need, and wrap it in electrical tape.

[opethmike]

I used electrical tape for my current EFI harness, it looks wonderful :biggrin:

I'm planning on re-doing that harness as well. While my setup works very nicely right now, my engine bay looks very sloppy, and I'm not a fan of that.

I'll be sure to post before/after pictures of my clean-up.

[Farrar]

The original covering wasn't even electrical tape -- in my engine compartment anyway, only the ends of the wraps had adhesive on them. I could tell which wiring insulation had been damaged and re-covered by a previous owner/mechanic because although it looked the same it had sticky goo underneath. :P

I used Dave Delman's handy pinout of the bulkhead connectors to determine what I could remove, unwrapped everything, and stuck what was left in split wire loom, fixed with cable ties. (I did use silicone tape for extra heat protection on the wires that go down the front and sides of the engine, though it's underneath the loom so you can't see it.) The end result is not gorgeous, but it looks OK to me. Now if I had been really dedicated to having things look good back there, I would have shortened a lot of the remaining wires by removing several inches, then soldered everything back together and wrapped it up -- but that's a long project for another day.

[Spittybug]

VERY nice looking harness. Planning on making more? I'd love to buy one; I could just remove the old harness instead of having to unwrap, remove wires, re-wrap.

I noticed in the list there that you only listed one oil sensor. There are two; you're wiring for both, right?

One oil light (main harness) and one oil pressure sender (passenger side harness). I've considered making more, but I'm finding that different people have different ideas of which way to run it and different connectors on sensors (PO butchery in some cases) and that makes it difficult to commoditize them..... I got the loom from Fry's, used standard bullet connectors that I crimped down to the dimensions of the ones in our plugs, and slide them right on the pins in the bulkhead connector. The key is using electrical tape at the places where looms join or wires exit (stability) and covering the joint with shrink tubing for aesthetics.