I6 intake manifold heater wiring help needed (w/ diagram)

[Flex BT]

In an effort to help the problem I'm having with my starting problem (cranks for about 10 seconds before starting) I was advised to hook up the intake manifold heater. The wiring for this was completely removed by the PO. I ordered the relay and know it needs to be hooked to power, the manifold heater, the temperature switch on the manifold, and the oil pressure sender. My understanding is that it is made to send power to the heater only when there is oil pressure and will turn it off when the temperature sensor for the manifold passes a certain level. Other places I've read that the power should be coming from the same source as my electric choke power line. Clearly my understanding may be flawed as there are 5 connections on the relay. Here's the diagram and the connections (which were kindly installed upside-down in the case to make it extra confusing for me).





The other question I had was how long does it take for the manifold heater to work? I'm all for trying anything here that will help improve the health of my jeep it just seems like the heater wouldn't get warm enough within 10 seconds to make a difference. Please tell me I'm wrong and this will automagically fix my issue.

 

[IOPort51]

to try to explain relays, you are on your own with the heater itself, the 86 and 85 terminals are the coil. If 85 is supplied with DC+ and the 86 is supplied with DC-, or in our case ground, the "switch" will "make". the terminals between 30 and 87a are "normally open. this is to say that when the coil is not energized the 30 to 87a "switch" is not closed. the 30 to 87 terminals are "normally closed, this is saying that when the coil is energized the switch is no longer closed.

when you put 12VDC on the 85 and 86 terminals you will hear it click. this is the sound of the switches changing. Keep in mind that "normal" is the position of the switch in the box setting on a shelf.

In an effort to help the problem I'm having with my starting problem (cranks for about 10 seconds before starting) I was advised to hook up the intake manifold heater. The wiring for this was completely removed by the PO. I ordered the relay and know it needs to be hooked to power, the manifold heater, the temperature switch on the manifold, and the oil pressure sender. My understanding is that it is made to send power to the heater only when there is oil pressure and will turn it off when the temperature sensor for the manifold passes a certain level. Other places I've read that the power should be coming from the same source as my electric choke power line. Clearly my understanding may be flawed as there are 5 connections on the relay. Here's the diagram and the connections (which were kindly installed upside-down in the case to make it extra confusing for me).





The other question I had was how long does it take for the manifold heater to work? I'm all for trying anything here that will help improve the health of my jeep it just seems like the heater wouldn't get warm enough within 10 seconds to make a difference. Please tell me I'm wrong and this will automagically fix my issue.

 

[Torxhead]

This is an underhood wiring diagram for my '86. It does show the wiring diagram for the manifold heater in the lower right hand corner. One issue I had was taking a long time to start on a cold engine. It turned out to be gas evaporating from a hot carb and manifold after shutdown due to a bad carb float bowl vent system.

 

[Flex BT]

The diagram is too small to read. From what IOPort says, I think I'm supposed to hook it up like this:

30 - 12v from battery
87 - Manifold heater
86 - Oil pressue switch
85 - temperature switch
87a - blank out / cover

Does that look right? I'm guessing the temperature switch acts as a ground until the temperature is high, then it ceases to be a ground somehow and the gate closes?

My carb is a Weber 38, another thing I'm doing is replacing the charcoal canister so maybe that will be what actually helps. Torx, was it something you had to send back to the manufacturer or something you repaired yourself?

 

[Torxhead]

You might get an easier to read schematic if you print it out. I have the oem Bosch relay p/n ef 8933001779, with the same connection #s.
#87 is a hot line from a fusible link(red).
#86 is to the choke heater(red w/white tracer).
#85 is to the manifold heater switch(green).
#30 is to the manifold heater(orange).
# 87a is empty, since only 4 wires to the relay.
I used a Standard CP3045 for a charcoal cannister and have since converted to fuel injection.

 

[Flex BT]

Well I thought there was enough frayed wire sticking out to get a crimp on. Unfortunately, I was wrong. Is there any way to get another wire in there without taking the whole manifold off? I can't see underneath this thing really well but it looks like there's a concave section where the wire comes out, if I can get the bottom plate separated a little bit can I just stick another 10 / 12 ga wire in there and close the plate back again? it looks like I'll be able to get the plate loose but it would be impossible to remove it completely because the exhaust manifold is about 1/2" away from the bolt on the back of the plate. Any kind of soldering operation would also be next to impossible just from the angle trying to get around everything to the bottom of the plate.

Basically, is the plate just crimping the wire underneath the convex part or does that wire start being insulated and go up someplace else inside the heater to connect?

 

[Torxhead]

Looking at mine. it seems like the heating element is up inside that cover and there is a clear plastic piece of insulation just prior to where the wire enters. So it seems like the manifolds have to come off to get close enough to work on it. Reading other forums the heater does seem to be a conveinient item to have. If you are going to try to deal without it I would recommend making sure you have at least a 195 degree thermostat and making sure your carb and choke are in good working order to try and get things warmed up asap during startup.