CIS Wiring Cleanup for EFI

[na2ub]

I'm in the process of cleaning up the CIS engine wiring harness, for a EFI/ITB build. (MS2 with MSD)

What I've done:
1) Removed the old wiring for my external Voltage Regulator (my car has a newer alternator with the internal regulator.

2) Removed the Heater Blower wiring (tied in with the VR wiring ground) as I will be backdating heat.

3) Removed the CIS Cold start valve wiring (2 wires to thermo-switch, 1 wire to starter)

However, I am a little stuck on two remaining circuits, so I could use some help.



A) Circuit 1 in Purple. Red / white travels from pin 10 in 14 pin connector to Warm up Regulator connector. Then it travels from the WUR to the Auxiliary Air Regulator. Then it travels to its final destination, marked 'what is this' in the picture. They all share the same ground, from the alternator, following the same path.

B) Circuit 2 in Green. White 2 pin connector (bottom right in the image) plugs into a receiving connector, by itself, off the harness in the left engine bay. Red wire goes to the 6-pin CDI connector. Other wire, brown/red, travels to the connector what was in the back (left) of the CIS system, marked 'Not Cold Start Valve' in the image. The connector marked 'Not cold start valve' is grounded (by itself) to the alternator.

So, for Circuit A, can I remove this entire circuit? What is the plug for at the end of the run?

For Circuit B, do I retain the white connector, to power the MSD? What about the brown/red to the CIS endpoint, I cannot name?

I think once I get these cleaned up, I should be able to re-wrap the original harness, and move on to wiring up the MS2 and MSD.

[timmy2]

A- remove all. The device plug is for the time delay vacuum switch.
B- keep white connector to CDI (switched power to 6 pin of original CIS, if making the MSD plug and play to the original 6 pin connector. Or delete, and run a new wire from the body side plug for MSD switched power.
Remove brown/red coming from air flow switch connector for fuel pump circuit cut out. Maybe tie in a 5 pin relay to make the pump run from the MS2 (lift a ground on energization)

[na2ub]

Originally Posted by timmy2

Remove brown/red coming from air flow switch connector for fuel pump circuit cut out. Maybe tie in a 5 pin relay to make the pump run from the MS2 (lift a ground on energization)

I suspected as much, with the rest of the wiring, but this piece I do not understand. I did see that this circuit was somehow related to the fuel pump. Does the brown/red provide a ground to the fuel pump relay in the front of the car?

Thanks!

[timmy2]

Read up on the reverse relay action of the fuel pump.
When the brown red wire is grounded, as in a stalled engine situation that makes the air flow switch become grounded when it closes, it actuates the coil and kills power to the fuel pump.
Here is a drawing I made up for microsquirt for someone, using the existing 78-83 wiring. Fuel only setup.
MS2 wiring is similar but has different terminals and wire colors at the ECU connector.
You’ll need to figure out and wire in your MSD as well.

[na2ub]

Will do. Thanks! Schematic is helpful.

[AlKidd]

If you search the forums Dennis posted the parts to make an adapter to mate the factory CDI connector to the MSD box. Like in his drawing, I used the red wire of the T connector to switch a relay and power a small fuse block that I mounted on the aluminum CDI panel. Off of the fuse panel is the injectors, MSD & wideband.

[TargaWoods]

I'm Also redoing my wiring after an engine drop post-efi conversion.

Removing CSV. Is that chain cover temp sensor also vestigial now? can those wires be removed?

Directly to the right of the crankcase breather plate, there is a red plug with a flat spade connection, and a flat plate (similar in shape/ outline to an intake gasket) what does both that plug, and plate, do / what are they called?

[PeteKz]

I may be wrong, but when I traced the wires on my SC engine, I found that the wire to the air control unit that grounds, controls the CDI rather than the fuel pump. If it's not grounded, the CDI stops working. Maybe it cuts off both. But be sure your CDI gets that ground too. I wouldn't try to simplify the old wiring, but I'd make a new wiring harness and keep the old one for reference.

And if you remove the CSV, then the chain case temp/time switch becomes inoperative too.

[na2ub]

The thermo switch on the left, top timing chain cover, is part of the CIS system, and only feeds signal to the cold start valve on the CIS system. No CIS - no need thermo switch. (Mine was replaced with a regular temp sender for the new efi.) See the top of this post. The CSV only connects to the thermo switch, and pulls power from the starter (3 wires total).
The temp switch next to the crankcase breather, is responsible for illuminating your temperature light in the dash (if the engine is too hot). The circular flat plate, next to it, is the oil cooler thermostat. No need to mess with this, unless you want to replace the o-ring, inside. This contraption, similar to the external thermostat in the right rear wheel well, used a wax plug to open the flow of oil to the engine oil cooler, once the oil is hot.

Cars/years may vary. I'm speaking to a 79 US SC.