Engine System Wiring Digrams

[OverKnight]

My son (EagleJoe93) and I are still plugging away at getting his 1986 Eagle on the road.  I just haven’t had the time to really get my head into figuring out some of the details regarding some of the underhood wiring and vacuum lines, and for a 19 year old with his first car, his patience has been astounding.

Engine-wise, here’s what we’ve done:

• installed Gronk’s Motorcraft 2150 carburetor
• removed and reinstalled the intake and exhaust manifolds due to leaking gaskets
• installed an aluminum rocker arm cover
• removed EGR valve due to it being damaged and also due to the tube between the intake and exhaust manifolds being damaged
• installed a new catalytic converter

We have the parts to do the TFI upgrade, plus new spark plugs, battery cables, all fluids and more.  It’s unfortunate that it’s taken us this long (we bought the car in January 2012) because thinking we’d get thing done sooner, I wasn’t as careful as I should have been during disassembly, and I didn’t mark hoses and wires as carefully as I should have (who among us hasn’t done this?), so now I’m trying to figure everything out.

Currently, the EGR valve has been removed because: 1) it was clearly defective, 2) the tube.  We possibly intend to replace it at some point, but for now, there’s no EGR and I believe the thermal control valve in the intake manifold is also damaged and has been replaced with a simple metal plug.

What I really need are clear wiring diagrams for some of the engine systems.  I have three questions:

1)   What wires go to the electric choke and intake manifold heater?  How are the voltages to these regulated?  At this point we’ve removed much of the smog equipment from this engine (O2 sensor, EGR valve, and the Motorcraft only has h a simple air filter), so many of the inputs to the ECM aren’t there anymore.  I don’t see how the ECM can work without all of the inputs it was designed to have.  If possible, I’ like to keep the electric choke and manifold heater.
2)   We thought we correctly connected the temperature sensor and wire for the temperature gauge, but it’s not moving at all.  What wire should be going to the temperature sensor?
3)   What is the stock location for the negative battery wire on the engine?

For a later project, Joe and I picked up a head and exhaust manifold from a 1992 4.0 L Jeep, and I notice that with the header-style exhaust manifold there’s no EGR valve.  Were EGR valves used on these engines?  I did intend to replace the EGR valve on Joe’s car at some point, but if they weren’t used with the 4.0 L head, then we’ll be able to save on that expense.

Thank you.

[lapoltba]

I can start to answer some of your questions and others will probably chime in to add or correct as needed.

1.  Manifold heater runs to a relay on the passenger inside fender.  It gets switched power from a oil pressure switch ( not pressure sender for a gauge) located on the block rear of the oil filter.  This switch also controls the electric choke and is powered directly from the battery, not from the ignition key.  It is only switched on when the engine is running.

2.  Can't help here, but it is possible the sensor is bad.

3. Negative connects to the block by a ~1.5' long cable directly to the block just forward and above the passenger side engine mount. 

[Amc1320]

I recently did all of this so maybe I can try to help while it's fresh in my head

1. When you removed the egr did you put a cap on the hole there? If not it will be a huge vacuum leak and it probably won't run well, if at all
2. When you do the gronk conversion you really only need a very few vacuum hoses. Ported vac to dist from the carb is one, then the vacuum connection near the back of the intake goes to 4wd and the one just above where the erg used to be goes to the power brakes. I also has a vacuum gauge in my car so I used the extra one beside where the 4wd hooked up.
That's it, all the rest of the miles of hoses can go away, I did not use any of the cto's and plugged all of them up with brass plugs
You will have to bypass the computer for your ignition as well but without the old feedback carb you don't need it anyway
2. For the electric choke just any 12 v keyed power source is fine, I just fished around the harness of stuff I disconnected till I found one, no problems
3. I have never seen a manifold heater, these used water to heat the intake, not electric that I have ever seen?
4. Negative cable bolts kinda under the AC bracket to side of block

Hope this helps

[BenM]

lapoltba is right on the heater and choke; I swapped the aluminum intake into a Pacer and followed the Eagle wiring to do it. You'll need the rear temperature switch on the intake to ground the relay.

The temperature sensor is on the back of the head near the firewall for the gauge. It needs to ground through the head, so make sure you didn't use any sealer, threadlock, or teflon on it. The gauge will peg hot if you hold it to ground with the ignition on. Don't do it too long or the gauge will burn out.

[OverKnight]

Thanks, everyone, this has all been helpful.  We’ll look for the relay on the fender; it’s possible that it’s not getting a 12-volt feed, because I’m pretty sure the wires for the electric choke and manifold heater are correctly connected.  The temperature gauge was working when we bought the car, but since I’m big on the use of anti-seize, we’ll check that we didn’t apply it to the temperature sensor (I probably did).

We’ve installed the vacuum lines pretty much as Rob has described, with everything else plugged off.  Once the car is running properly, we’ll begin removing the unused hoses and wires.

The EGR valve is still installed, so there shouldn’t be a vacuum leak, but we’ll fabricate a block-off plate to ensure that there are no leaks until we decide which way we’re going with the EGR system.

The reason I asked about the location on the engine of the negative battery cable is because it is connected to the aluminum bracket for the AC compressor.  To me, connecting this cable to aluminum is at best an adequate connection which will only deteriorate over time.

Thanks again.

[BenM]

Here's a diagram from a similar year jeep to see the wiring layout. (Click for big)

[OverKnight]

Thanks, Ben.  I guess the trick now is to first find these relays (it’s still something of a mess under the hood!), and then make sure the connections coming and going are correct.

[ammachine390]

Thanks, Ben.  I guess the trick now is to first find these relays (it’s still something of a mess under the hood!), and then make sure the connections coming and going are correct.

The manifold relay is located next to the starter solenoid. There should be two relays there, a square one, which is the manifold heater relay, and a rectangular looking one, which is for the horn.

[Amc1320]

Hey overnight, didn't mean to lead you astray on the manifold heater, listen to the experts on that one

I removed everything when I rebuilt the engine then only added back what I absolutely needed to make it run good, so I eliminated a lot of stuff, and to be honest over the course of three years working on it I forgot where a lot of it went!

I only have like three wires and four vac hoses, I wanted it to look lime my 74 gremlin under the hood, simple and easy to work on

That's why there guys on here are so handy to have around, in case your memory is like mine....

[OverKnight]

Thank, Dan.  We're only able to work on this car on the weekends (if we're lucky) so we'll look for these then.  Thanks for the help, and we'll let you know what we find.

Don't worry, Rob, you can do nothing to make us more lost than we already are!