Howell EFI/TBI Install 1990 Jeep Wrangler

Howell EFI/TBI Install 1990 Jeep Wrangler

Complete review and tips for installing the Howell fuel injection system on a 1990 Jeep Wrangler YJ using Chevrolet throttle body and Howell-modified computer.

29
Like
Save


Comments

tinderboxarts says:

Anthonie Galvan–I’m not sure a follow your question, but I suspect you may
have become confused about the directions for your model year. There are
differences in the wires that you describe depending on model year. Go
back to the Howell directions (linked in the comments here) and double
check that you used the right procedure for your model year.

Rokon Revolution says:

Thanks for your time and efforts to share your experiences. I’m in the
middle of the conversion, and your sharing has saved me much time and
probably $$… Tech support should be your handle…
Things worthwhile usually take longer than anticipated….

john tychsen says:

Question? What wiring did you use for the supplied fuse box? Will one of
the switched yellow wires left from the ecm removal work that is switched
power? Also I didn’t run the manifold heater relay wire. I never had the
green wire coming from my manifold so I just reconnected the wire that it
originally had I also went through allthe wires and never saw it being
affected by wire removal.. I used your video for guidance thanks, Also my
manual said to connect the vacuum from port A off the howell tbi , you used
J? Do you think it matters? The other one I capped.

STEPHEN PORTER says:

Thank you so much for the vid. I pulled the old computer out, and messing
with the wires now. I cut “ALL” the wires associated with the bundle to the
batter tray, and then your vid showed me I needed the relay for the
manifold heater. So i’ll be re-solidering, thanx for pointing out the two
yellow wires, one will go to the heater manifold, the other is going to be
power to the HEI ignition.

Anthonie Galvan says:

hi, we spliced in the supplied purple wire to # 18 purple wire from
original module and jumpered #47 & 59 together. i assume this is the signal
for injector pulse from distributor, but it does not tie into the howell
ecm since the original harness is disconnected, so we have no injector
pulse. did you run into the same problem? how does the howel ecm pick up
the distributor signal when the original harness is now unplugged?

STEPHEN PORTER says:

I’ve been going over and over through your vid…my engine just showed
today.

rag Doll says:

Hey tinderboxarts!
I’m back… 🙂
I’ve finally converted my cj7 to the gm tbi… But the ecm is flashing the
codes: 42 and 43.. Meaning it has no spark control.. –I guess because I
DIDN’T install it.. Any suggestions on how to make it go away OR what
distributor to get to allow the ecm to control it? I’ve already tried to
connect the b7 to c11 to fool the computer.. But the check engine light
still illuminates and runs like a dog… :(

STEPHEN PORTER says:

Great vid, I’m swapping my engine in a couple of weeks, slowly getting
parts together that are more robust rather than reuse. I put a weber carb
on last year. it helped (sort of) but I’m going to do the howell with the
new 258. question though.did you swap out any ignition? I did the nutter,
but would’t start so shifted back. I was thinking of doing a different
distributor and coil.

millertime021 says:

Do you remember which wire you used for the crank and run 12V source for
the CPU? Did you use the ‘start’ (green wire) for that, or did you even
end up using that one?

crruzzzer1 says:

Nice Video. It’ll definitely help with my install that I’m planning this
summer. Right now I’ve swapped mine to a Motorcraft 2150 Carb. It runs
really well but I live In Cali and the smog dogs are upon me so the swap
makes sense. Now my questions. Did you see any increase in mileage? How
about power? Sure would be nice to see and hear it run… Thanks for the
Vid…

rag Doll says:

By the way, do you have a video of the jeep running and driving with the
howell efi? :p

copperdog007 says:

Did you ever find out what the orange and black wires were for? the ones
behind the defroster duct. I am half way done with this install on my 87
YJ.

iphantom1er says:

Where can I find a dual cto valve? I have a 89 yj and have the same
configuration under the hood, and same Howell conversion kit. I stumbled
across this half way through the conversion, my cto valve is toast, and I’m
having the hardest time finding one. I can’t find one anywhere. 

millertime021 says:

Awesome vid, thank you. I’m mid install and this video has been the most
helpful thing so far.

Quick question. The two pin connector on your duraspark ignition, does it
plug into a plug with green and yellow wires? Mine have red and white going
from ignition to plug, but I can’t remember what plug went back in. (I took
a *long* break during this install)

rag Doll says:

Hi again,
Thanks for your review and upate.
I updated my intake manifold with an 1985 intake and a new exhaust manifold
that already has the O2 sensor port.
Does Howell offer a Throttle Body with a kickdown/passing gear bracket? (I
have a TH400 auto trany behind my 258.
Am I correct to say rhe ECM is pre-programed and is NOT a ;earning computer?
Did you have to do any throttle body adustments or is it plug and play?
Also, I don’t have a computer/brain in my cj7.. Hopefully it will be easy.
Thanks :)

tinderboxarts says:

The kit has worked without a hitch, even as the weather turned colder. Once
in a while the RPMs take a few seconds longer than seems necessary to come
back to idle when I pull it out of gear (I have a manual) but that’s REALLY
minor. On your ’76 the kit would be even easier to install, except that you
might need to weld in the bung for the O2 sensor in your exhaust. Anyway, I
have no complaints about the system–it just starts and runs now with no
drama.

tinderboxarts says:

I bought it directly from Howell on the theory that they would be more
eager to provide support if I bought it from them. It was the same price as
in the catalogs. But, I ended up figuring it all out for myself anyway.

Chase Tenety says:

Where did you buy the kit?

jeepjeeplady says:

Would you still recommend the kit? I have a 76 cj7 and hate the carb. I’ve
never owned a carb car. I am considering replacing the mc2150 carb with a
efi/tbi kit. THanks for the video 🙂

Write a comment