Howell and HEI - JeepForum.com
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post #1 of 28 Old 07-28-2021, 09:24 AM Thread Starter
Derekwh
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Howell and HEI

I am going to be installing a Howell EFI and a HEI distributor in my '85 CJ7. I am looking forward to cleaning up all the excess vacuum lines and wiring. Just so that I don't over do it I thought I'd check. In addition to removing the coil and its wiring I assume I can remove the ignition module and its wiring. Is this correct? Is it okay to remove the diagnostic plugs and the attached wiring?

Thanks,

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post #2 of 28 Old 07-28-2021, 10:02 AM
victex
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I just did an HEI in my previously nuttered 85 last week. After install, the Jeep still wouldn't start. I spent about an hour tracing wires back and forth looking for a loose connection or ground before I got tired of trying to decipher everything and just cut the PCM harness at the firewall and the diagnostic port bundle at the plug. Then I started the Jeep to make sure all the gauges worked, pulled all the wiring out of the loom back to the driver side and cut off anything that was not connected on the other end except the wire for the electric choke wire which I shortened and spliced back together.

The ignition module went in the trash as well. I retained the hot wire going to the module and jumpered from it power the HEI.

I am still running a Weber, so I am not sure about the EFI. I can't promise that your setup isn't different, but that is what worked for me.
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post #3 of 28 Old 07-28-2021, 12:33 PM Thread Starter
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Thanks, that is the answer I'm looking for. I hear the trick is to make sure that your hot lead to the distributor is the one that remains hot while the key is in the start position. I am putting the HEI in first to confirm that the engine runs before i put in the EFI.
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post #4 of 28 Old 07-28-2021, 07:14 PM
Mongo228
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Quote:
Originally Posted by Derekwh View Post
I am going to be installing a Howell EFI and a HEI distributor in my '85 CJ7. I am looking forward to cleaning up all the excess vacuum lines and wiring. Just so that I don't over do it I thought I'd check. In addition to removing the coil and its wiring I assume I can remove the ignition module and its wiring. Is this correct? Is it okay to remove the diagnostic plugs and the attached wiring?

Thanks,
I put in the Howell EFI with the original Duraspark, and it wouldn't start. The Duraspark box had finally decided to kick the bucket.

I installed HEI ... and I couldn't be happier. It cranks out 60KV. I gapped my plugs to @ .047-.050, the ignition is happy as a clam, and the plugs are indicating proper gap characteristics/coloring.

I removed the entire Duraspark system, lock, stock and (non-)smoking barrel. I basically have one hot wire to the "BAT" connection on the HEI, and two tach signal wires to "TAC." One is for the factory tach (mine is/was a Laredo), and one is for the EFI (Howell needs a tach signal to run).

I'm still tweaking timing to find the "sweet spot," but I love the HEI ... much cleaner, simpler design. So, yeah, if it's Duraspark-related, you can eliminate it.

Luck to you!

Dave
Mesa, AZ

"Grinders and Paint Make You The Welder You Ain't!" -- from a t-shirt
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post #5 of 28 Old 07-29-2021, 09:01 AM Thread Starter
Derekwh
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Thanks, my goal is to get rid of the extra wiring. It is hard to believe the these simple, utilitarian vehicles have so much wiring and tubing.
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post #6 of 28 Old 07-29-2021, 03:57 PM
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Originally Posted by Derekwh View Post
Thanks, my goal is to get rid of the extra wiring. It is hard to believe the these simple, utilitarian vehicles have so much wiring and tubing.
Gotta love the smog parts from the 80's lol. The instructions that come with the Howell kit are pretty good. It lists everything that can be removed. Just take your time and verify everything before you start cutting wires.

I would only do one or the other (howell or hei) and then make sure everything's running well before moving onto the other. You'll barely recognize your engine compartment after you remove all the crap in there. Hands down one of the best mods i've put in my jeep.

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post #7 of 28 Old 07-29-2021, 04:14 PM Thread Starter
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it seems that they just threw wires and vacuum tubing at the smog issue, I'm looking forward to a clean(er) engine compartment. I installed the HEI first and confirmed the she ran okay. I decided to replace the intake and exhaust manifold and valve cover gaskets while I was in there, I figure it is a good time to chase down the leaks. I haven't even looked into the Howell box yet.
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post #8 of 28 Old 07-30-2021, 10:39 AM
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Quote:
Originally Posted by Derekwh View Post
it seems that they just threw wires and vacuum tubing at the smog issue, I'm looking forward to a clean(er) engine compartment. I installed the HEI first and confirmed the she ran okay. I decided to replace the intake and exhaust manifold and valve cover gaskets while I was in there, I figure it is a good time to chase down the leaks. I haven't even looked into the Howell box yet.
When I opened the Howell box, it was a bit daunting, but it comes with pretty good instructions.

Check your engine for the five-port CTO switch they want you to use. I got this one from Amazon in case you need one quickly. Note, the switches are pricey!

Since Howell has been around for so long, there is plenty on the internet if you run into trouble, and the is the option to ask here.

I went with an American Autowire harness to replace the original wiring. My engine compartment looks a bit of a hot mess, but that's on me. This is my first restoration, so I'm learning as I go.

A circuit test light is your friend if you don't already have one!

As long as you follow the Howell instructions, you shouldn't run into any serious difficulties,

Dave
Mesa, AZ

"Grinders and Paint Make You The Welder You Ain't!" -- from a t-shirt
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post #9 of 28 Old 07-31-2021, 06:20 PM Thread Starter
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I already had the CTO switch and the other required pieces. I am in the process of doing some other stuff like gaskets and motor/trans mounts, I installed the pump and speed sensor while under the car. I pulled out the old ECM, what a crazy amount of wiring! My engine compartment is filled with what seems like miles of wire.
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post #10 of 28 Old 08-01-2021, 09:53 PM
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Quote:
Originally Posted by Derekwh View Post
I already had the CTO switch and the other required pieces. I am in the process of doing some other stuff like gaskets and motor/trans mounts, I installed the pump and speed sensor while under the car. I pulled out the old ECM, what a crazy amount of wiring! My engine compartment is filled with what seems like miles of wire.
So, I'm guessing you already had a hole in the firewall for the harness since you already had an ECM to remove? Or was your ECM in the engine compartment? If you have the pre-made hole, I hope it makes running wires easier for you. I followed Howell's instructions on drilling a hole in the FW for mine; wound up creating a 1/2" deep clearance flap to get some of the parts through.

I know what you mean about "miles of wire." My engine bay looks a bit of a hot mess; I need to get in there with some cloth tape and "clean up" the rat's nest.

Did you end up with a filter that looks like a small coffee can?

Dave
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"Grinders and Paint Make You The Welder You Ain't!" -- from a t-shirt
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post #11 of 28 Old 08-02-2021, 08:55 AM Thread Starter
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I had the oval hole near the battery with the rubber/steel grommet, I cut a slot in the grommet so I could get the old harness out and the new one in. The connectors barely fit through the hole. I have the "coffee can" canister under the battery with no connections to the two nipples. I also have the vacuum canister under the master cylinder that has the vacuum hose.
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post #12 of 28 Old 08-04-2021, 12:05 AM
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Originally Posted by Derekwh View Post
I had the oval hole near the battery with the rubber/steel grommet, I cut a slot in the grommet so I could get the old harness out and the new one in. The connectors barely fit through the hole. I have the "coffee can" canister under the battery with no connections to the two nipples. I also have the vacuum canister under the master cylinder that has the vacuum hose.
Nice! Sorry you had to make some cuts, too. I think Howell might need to re-think their sizing on the holes.

I'm drawing a blank on the canister under the battery you're talking about, but most Jeeps post 1975 (I THINK!) have the evap canister under the brake master/booster. With the Howell, one of the 4 ports gets capped.

Beware vacuum leaks! I've read a ton of posts around the 'net about people running into issues with the throttle body not sealing proper to the adapter plate, or the plate not sealing properly to the manifold.

Dave
Mesa, AZ

"Grinders and Paint Make You The Welder You Ain't!" -- from a t-shirt
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post #13 of 28 Old 08-04-2021, 09:53 AM
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Usually you have to cut a small line in the metal/rubber oval grommet to remove the stock wiring. There's no way around that. Most just reuse it with some automotive caulk/sealant. It would be nice if Howell supplied a new one, but I'm sure due to differing ECM placement and wiring install lengths they don't do it, as they would have to set it so it wouldn't leak.

The canister under the brake booster is the evaporation canister (used in the howell install)...the canister under the battery is the vacuum reservoir (not used in the howell install, but is used for the stock setup). Links with more info below and a good resource in general.

evap can:https://gleebledorf.com/evaporat.html
vac res:https://gleebledorf.com/vac-res.html
main link:https://gleebledorf.com/
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post #14 of 28 Old 08-04-2021, 10:57 AM Thread Starter
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I was able to cut a slit in the grommet to get it off the old wiring and use for the new. It worked well. I was able to squeeze the new plugs through oval hole without trouble. Thanks for the explanation about the vacuum reservoir.
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post #15 of 28 Old 08-04-2021, 04:12 PM Thread Starter
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I have a fuel line question, is it correct to assume that it doesn't matter which fuel port the line from the pump goes to, and the pressure relief hose goes to the other one?
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