AMC401 Howell TBI fuel only

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ferrum
Posts: 131
Joined: Sun Jun 19, 2016 1:49 pm

AMC401 Howell TBI fuel only

Post by ferrum »

My TBI is finally working great. Just in case there's anyone else out there that purchased Howell TBI kit and having issue getting it to run right, there may be an answer.
I got my Howell kit about 2 years ago. What sold me was the key word phrase "turn key". I was able to get it installed got my engine fire right up but rough and rich with my original intake. Found out my 4v intake was not compatible so installed Edelbrock performer intake without EGR. Performed minimum idle adjustment and got it to run better. That was about 2 years ago. I had hesitation when engine was cold but when warmed up, it ran okay. I originally had it hooked up to manifold vacuum which gave me issues when engine was warmed up. Then I tried ported vacuum which was fine warmed up but gave me more rough cold start. Then I tried CTO and manifold when under 160 then to ported. I just couldn't get rid of cold engine hesitation. One benefit of TBI was remote auto start. For the most part during winter, I just let it warm up and then go. Still better than carb. Even in the summer time, I have to feather the gas pedal when engine is cold to minimize hesitation.
I worked on it off and on for a while to see if I can get it better. I couldn't get much help from Howell. I really wanted to get it run better before this winter. This was accomplished by getting help from HamiltonEFI. He sent me a tuned chip for fuel only setup that took care of my issue. I can now turn on the engine and put it in gear and drive out without hesitation right away without waiting for warm up. No more feathering gas pedal until engine warm up. It is well worth spending $160.00 for custom tune to fix $1500.00 mistake.
'76 Cherokee Chief
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HIGHCountry
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Re: AMC401 Howell TBI fuel only

Post by HIGHCountry »

Hey, I know this has been quite a while since you posted this. I was able to find a brand new Howell kit for a discounted price. I am going to go get it next week. I have not inspected the tbi system and have not become familiar with what components facilitate what functions, but are you saying that this chip is a supplement to the system? Does it engage the new fuel injection computer/ecu directly? Thanks a bunch, JW
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Renodemona
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Re: AMC401 Howell TBI fuel only

Post by Renodemona »

The chip is inside the ECU. For the money, go with Fitech, especially if you have a square bore manifold.
"Wait, what's on fire!?" KJ7TCT
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1976 Cherokee w/t 'Susan' 401/TH400/QT(PT)
FiTech Go EFI, Edelbrock Performer intake
3" Rough Country Springs, HEI Dizzy
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2018 Cherokee Trailhawk V6 'Sedna'
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HIGHCountry
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Re: AMC401 Howell TBI fuel only

Post by HIGHCountry »

FiTech is more expensive than the complete Howell kit that I found, even with a $160 chip swap.
If anyone has done that chip swap, does the Howell perform well once it has been swapped? I know that this is probably a rare situation, but...
Thanks
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FSJ Guy
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Re: AMC401 Howell TBI fuel only

Post by FSJ Guy »

You can reprogram a "Howell" system easily, since it's a GM TBI system fro the early 90s. See my website for details. You'll need to invest in a few hundred dollars worth of hardware and need a Windoze computer (laptop preferred for cataloging) and will need to be comfortable with Windoze. If right clicking is foreign to you and you don't have time to learn, you may be better off paying someone.

Otherwise, tuning a TBI system yourself is loads of fun!!!
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!

Topic author
ferrum
Posts: 131
Joined: Sun Jun 19, 2016 1:49 pm

Re: AMC401 Howell TBI fuel only

Post by ferrum »

Since I had Bill with Hamilton EFI reprogram the chip, I have not had any issues I had with original Howell programmed chip. Basically, I can start the jeep and drive off without having to worry about hesitations, rough idle. With Howell chip, engine had hesitations and rough idle when engine is not warmed up and when engine warmed up, idle rpm would try to go down to 600 rpm which did not work well with 401 but drivable. However, it annoyed crap out of me that I had to warm up the engine for few minutes in summer time or nurse it along for a few minutes. Now, it even starts when outside air temp is -20 degrees F. Best part of it is being able to use remote start when it's cold out. :D
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babywag
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Re: AMC401 Howell TBI fuel only

Post by babywag »

ferrum wrote:Since I had Bill with Hamilton EFI reprogram the chip, I have not had any issues I had with original Howell programmed chip. Basically, I can start the jeep and drive off without having to worry about hesitations, rough idle. With Howell chip, engine had hesitations and rough idle when engine is not warmed up and when engine warmed up, idle rpm would try to go down to 600 rpm which did not work well with 401 but drivable. However, it annoyed crap out of me that I had to warm up the engine for few minutes in summer time or nurse it along for a few minutes. Now, it even starts when outside air temp is -20 degrees F. Best part of it is being able to use remote start when it's cold out. :D
That's because one size fits all doesn't exist. Too many variables even between similar engines.

ALL FI systems need to be "tuned" whether it's a custom chip, or via a handheld like the new aftermarket systems use.
ALL FI systems are self learning/self tuning, but again they need to be tuned to work best.
Renodemona wrote:The chip is inside the ECU. For the money, go with Fitech, especially if you have a square bore manifold.
The marketing spin on the new ones is misleading, they require tuning to work properly just like any other system.
Will it work if you take it out of the box and slap it on/drive it. Probably...but it'll work a whole lot better if you "tune it".
They are clever and don't call it "tuning", but what do you think changing settings via a handheld unit is exactly?

Both systems have pros/cons...IMHO a marriage of them would be best.
Fitech or similar throttle body, and GM computer.
-Tony
'88 GW (aka Babywag)
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