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post #1 of (permalink) Old 06-15-2004, 11:28 PM Thread Starter
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Manifold heater wiring with MC 2100 conversion

1985 CJ7, 258, MC 2100 conversion, points ignition.

Okay, just about got everything wiring wise straightened out under the hood. The only thing left seems to be the manifold heater. The jeep has been running without it for a while, but is cold blooded until warmed up. Since here in Alaska "colder" starts are the rule, I thought I'd get it back in service.

I've visited a couple of excellent websites (links gotten from members here), but they only mention the manifold heater in passing. From what I gather there was a "hot" wire running to a relay, a wire from the relay to a temp sensor that controls it (that wire is green according to the websites I looked at) and a wire to the heater itself under the carb. However, one site mentions a wire running from the stock carter BBD to the relay as well! That is what is throwing me!

I have what I believe to be the correct relay (already cut out when I got the jeep). It has an orange wire running to it that is always hot. It has a fairly substantial red wire with a white stripe running out of it that has been snipped. Right at the relay plug in is a green wire that was snipped.

So the question is, if I run the red and white wire to the heater, a new green to the switch and leave the orange hooked up to the always hot circuit it is on, am I good to go?

What makes me hesitant is that the wire feeding the relay is always hot. Seems to me that would want to be on a circuit that only comes on when the engine is in the run position.

Any help would be greatly appreciated.
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post #2 of (permalink) Old 06-16-2004, 02:09 AM
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Re: Manifold heater wiring with MC 2100 conversion

I don't know about your specific application or even CJ's but the red wire with the white stipe on my YJ is Ignition hot.

Just FYI.
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post #3 of (permalink) Old 06-16-2004, 03:39 AM
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Re: Manifold heater wiring with MC 2100 conversion

1. IMHO, the easiest way to energize the Manifold Heater,
2. Is to incorporate a rear-window defroster timer/relay,
3. From a donor vehicle.
4. It's easily wired,
5. And when the engine's started,
6. The manifold heater engages 4 - 5 minutes,
7. And automatically shuts down...
8. Another way is to trigger a relay,
9. Off the CTO switch...
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post #4 of (permalink) Old 06-16-2004, 12:38 PM
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Re: Manifold heater wiring with MC 2100 conversion

If this helps. The manifold heater uses a temperature switch in the intake manifold that controls the intake heater operation. It has continuity below 160F and opens above 160F and turns the heater off. I tested my switch in hot water to check the operation.
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