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post #1 of (permalink) Old 12-13-2002, 11:07 AM Thread Starter
 
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Howell install questions

When you installed your new wiring harness, where did you pass the harness to the ecu thru the firewall?

How much factory wiring were you able to eliminate? I see alternator, headlights, guages, turn signals, running lights as all factory wiring to be sorted out from the rest. Any suggestions on what can easily be removed from under the hood?

I'm asking this not because I have a Howell kit and didn't get instructions, but am installing my Megasquirt and don't see the need to re-invent the wheel if others have come up with good solutions. I plan to mount the new ECU near the glove box. How to get the wiring thru the firewall it troubling me.

Anyone know if the main connector on the drivers side firewall simply unplugs leaving one half on each side?

Thanks,
Tim

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post #2 of (permalink) Old 12-13-2002, 11:20 AM
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Re: Howell install questions

</font><blockquote><font class="small">In reply to:</font><hr />
where did you pass the harness to the ecu thru the firewall

[/ QUOTE ] Through the OEM ECM hole, using the existing grommet.
</font><blockquote><font class="small">In reply to:</font><hr />
How much factory wiring were you able to eliminate?

[/ QUOTE ]1. Grab the OEM ECM bundle exiting the fire wall.
2. Follow it down to the "main harness".
3. Cut it out from the "main harness."
4. Remove all wiring to the emissions sensors.
5. It cleans it up a lot!
6. I removed all OEM emissions gunk but the EGR.
7. It was left, but de-activated.
8. The Fusebox does split in half.. but you shouldn't need to do anythng with it.
9. Let me know if you want Howell Install instructions... I have 'em scanned.
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post #3 of (permalink) Old 12-13-2002, 11:25 AM Thread Starter
 
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Re: Howell install questions

Gulp,

I can cut out of the harness the entire mass of wires exiting the firewall thru the grommet on the passenger side?

Just want to double check before I do something so radical.
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post #4 of (permalink) Old 12-13-2002, 11:37 AM
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Re: Howell install questions

1. Yep, there is really a pucker factor here...
2. Look twice.
3. Cut once!
4. But really, none of the wiring going to the ECM is needed... it's now a parasite!
5. Check your Manitoba E-mail in abut 15 minutes.... and be prepared to download.
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post #5 of (permalink) Old 12-13-2002, 12:32 PM
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Re: Howell install questions

Don't cut it out, just take it out! If you unplug the original ECU, the whole harness should be able to be pulled through the grommet in the firewall intact. Then unplug all the sensors (you won't need anything off that harness anymore) and take it out as one whole piece and throw it up on Ebay! no cutting required.

All of the wires you will need to keep for the inside of the jeep are attatched to the block on the driverside firewall. Nothing in the wiring harness going to the stock computer are needed after this conversion.

Mike
post #6 of (permalink) Old 12-13-2002, 12:39 PM
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Re: Howell install questions

1. Mike, on a CJ you're only partically correct.
2. There are several wires that go to the ECM that join the main harness on the passenger side of the engine.
3. These wires must be cut out of the main harness.
4. This can't be done at the fuse block.
5. The other wiring to the sensors and vacuum motors, etc. do come off intact with the ECM harness.
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post #7 of (permalink) Old 12-13-2002, 12:49 PM
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Re: Howell install questions

Doh, I didn't realize that. I'm doing a slightly different swap, and I yanked all that stuff out intact no problem. Out of curiosity, what wires need to stay that went to the stock ECU?

Mike
post #8 of (permalink) Old 12-13-2002, 12:54 PM
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Re: Howell install questions

1. These go to the ECM and need to be removed.
a. Distributor Wiring.
b. Ignition Module Wiring.
c. Knock Sensor Wirnig.
d. 12 volt supply Wiring.
2. Wiring such as the Distributor and Ignition Module need to be respliced back to the main harness - left and right sides of the engine to complete the circuits.
3. It's really a very straight foward install, just a little daunting when you peel back the tape on that main harness.
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post #9 of (permalink) Old 12-13-2002, 02:17 PM Thread Starter
 
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Re: Howell install questions

Thanks so much for that information Leve (and the email of the instructions), I was really hoping you would be online today, as I know you have the Howell system. Actually it was through one of your posts that I learned about the Megasquirt project. I'm ready to install my system, as it is fully functioning on the bench.

Went out to the garage and removed that grommet thru the firewall and am pleased to have an opening sized large enough for the DB37 connector on the megasquirt harness. I'm locating the Megasquirt power and relay module on the passenger fender well above the starter relay. New ECU, near the old one. The Megasquirt harness fit perfectly in the old grommet and it looks like factory, I even re-used the old cable cover as I am thrifty (ok, cheap).

I hope to have the new ecu installed this weekend in order to ensure it likes the HEI's tach signal and voltage source before I swap manifolds and start tuning. I only wish my old 80 exhaust manifold had an O2 bung on it, as I'd like to see how the old carb fairs for mixture ratio.

Can't wait to clean up that engine bay of extraneous wire and relays.
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post #10 of (permalink) Old 12-13-2002, 02:23 PM
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Re: Howell install questions

</font><blockquote><font class="small">In reply to:</font><hr />
I only wish my old 80 exhaust manifold had an O2 bung on it

[/ QUOTE ]1. Get yourself a 22mm nut that'll fit the 02 sensor.
2. Drill the exhaust manifold.
3. Weld the nut to the manifold.
4. Ya gotta bung!
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