Howell Fuel Injection -
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post #1 of 6 Old 04-19-2013, 08:58 PM Thread Starter
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1980 CJ7 
Join Date: Sep 2010
Location: Park City
Posts: 63
Howell Fuel Injection

Hi Folks, I recently installed a Howell Fuel injection system along with an MSD ECM and a Performance DUI distributor and MSD wires on my 1980 304 cj7. She started up and ran okay but I have a severe hesitation when I step hard on the throttle from Idle. I checked the timing and tried settings from 5 BTDC all the way to 18 BTDC. No improvement. I double checked the timing mark against TDC on the number 1 cylinder and that is good. I can't find any vacumn leaks. Any suggestions? Thanks, Jack

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post #2 of 6 Old 04-22-2013, 04:52 PM
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1930 VJ 
Join Date: May 2009
Location: Wyoming
Posts: 1,279
So what does Howell say?

Pull my finger
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post #3 of 6 Old 05-19-2013, 12:33 PM
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1979 CJ5 
Join Date: Nov 2012
Location: Pucker Huddle
Posts: 7
I have the Howell FI with the DUI dizzy on my AMC 360. It ran pretty much the way you state, ended up that I needed to hook up the vacuum advance to a different port on TBI. Originally I set mine up just like a Chevy TBI but DUI told me it needed the opposite type of vacuum.
Too many years ago to remember if it was ported or non ported vacuum. Justed looked at mine and dizzy is hooked to small port on driver side of TBI in the front. Hope that helps.
RudeJeeper is offline  
post #4 of 6 Old 05-19-2013, 04:15 PM Thread Starter
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1980 CJ7 
Join Date: Sep 2010
Location: Park City
Posts: 63
Thanks, I had a plugged fuel injector that was causing the hesitation. That's fixed and she runs smooth except at idle. It has an intermittent miss at idle and a rolling idle plus or minus 150 rpm. It seems like the hotter the engine is the rougher it idles. Engine has about 6000 miles on a supposedly professional rebuild. I put a vacuum gauge on a port from the intake manifold and it has a nice steady vacuum pull of around 13 inches. Same with the port from the TBI unit. Nice and steady so I assume the valves are good. Howell said to replace the MAP sensor which cost me 60 bucks and didn't change anything. I hooked up a OBD1 and ran the winaldl software. The only parameter that looks out of spec is the IAC Units. The TBI tuner specs I have states that it should be around 15 IAC but will read higher at a higher altitude. I am at 4500 feet and it reads 35 to 60 at idle. Anybody have any ideas? One other spec that is slightly off is the TPS voltage. The spec is for a Chevy. Maybe my AMC is supposed to be lower but the Chevy TPS states .58 to.59 Volts. Mine is at .51 and if I try to raise the voltage the idle goes from 750 to 1400 rpm. Any help would be greatly appreciated. Thanks, Jack
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post #5 of 6 Old 05-22-2013, 06:14 PM
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1990 YJ Wrangler 
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Location: gwinett
Posts: 290
the low vac is your issue at idle. TBI does not like low vac.

90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
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post #6 of 6 Old 05-23-2013, 01:05 PM Thread Starter
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1980 CJ7 
Join Date: Sep 2010
Location: Park City
Posts: 63
Stock engine with a stock cam. I am not sure how to raise the vacuum or what would be causing a low vacuum. There should be plenty of vacuum with a factory spec cam. Any ideas?
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